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1. Photosynthetic microorganisms effectively contribute to bryophyte CO2 fixation in boreal and tropical regions

Author

Vincent E. J. Jassey, Samuel Hamard, Cécile Lepère, Régis Céréghino, Bruno Corbara, Martin Küttim, Joséphine Leflaive, Céline Leroy, and Jean-François Carrias

Subjects
Microbial ecology, QR100-130
Abstract

Abstract Photosynthetic microbes are omnipresent in land and water. While they critically influence primary productivity in aquatic systems, their importance in terrestrial ecosystems remains largely overlooked. In terrestrial systems, photoautotrophs occur in a variety of habitats, such as sub-surface soils, exposed rocks, and bryophytes. Here, we study photosynthetic microbial communities associated with bryophytes from a boreal peatland and a tropical rainforest. We interrogate their contribution to bryophyte C uptake and identify the main drivers of that contribution. We found that photosynthetic microbes take up twice more C in the boreal peatland (~4.4 mg CO2.h−1.m−2) than in the tropical rainforest (~2.4 mg CO2.h−1.m−2), which corresponded to an average contribution of 4% and 2% of the bryophyte C uptake, respectively. Our findings revealed that such patterns were driven by the proportion of photosynthetic protists in the moss microbiomes. Low moss water content and light conditions were not favourable to the development of photosynthetic protists in the tropical rainforest, which indirectly reduced the overall photosynthetic microbial C uptake. Our investigations clearly show that photosynthetic microbes associated with bryophyte effectively contribute to moss C uptake despite species turnover. Terrestrial photosynthetic microbes clearly have the capacity to take up atmospheric C in bryophytes living under various environmental conditions, and therefore potentially support rates of ecosystem-level net C exchanges with the atmosphere.

Published
2022
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2. Asynchronous recovery of predators and prey conditions resilience to drought in a neotropical ecosystem

Author

Thomas Ruiz, Jean-François Carrias, Camille Bonhomme, Vinicius F. Farjalla, Vincent E. J. Jassey, Joséphine Leflaive, Arthur Compin, Céline Leroy, Bruno Corbara, Diane S. Srivastava, and Régis Céréghino

Subjects
Medicine, Science
Abstract

Abstract The predicted increase in the intensity and frequency of drought events associated with global climate change will impose severe hydrological stress to freshwater ecosystems, potentially altering their structure and function. Unlike freshwater communities’ direct response to drought, their post-drought recovery capacities remain understudied despite being an essential component driving ecosystem resilience. Here we used tank bromeliad as model ecosystem to emulate droughts of different duration and then assess the recovery capacities of ecosystem structure and function. We followed macroinvertebrate predator and prey biomass to characterize the recovery dynamics of trophic structure (i.e. predator–prey biomass ratio) during the post-drought rewetting phase. We showed that drought significantly affects the trophic structure of macroinvertebrates by reducing the predator–prey biomass ratio. The asynchronous recovery of predator and prey biomass appeared as a critical driver of the post-drought recovery trajectory of trophic structure. Litter decomposition rate, which is an essential ecosystem function, remained stable after drought events, indicating the presence of compensatory effects between detritivores biomass and detritivores feeding activity. We conclude that, in a context of global change, the asynchrony in post-drought recovery of different trophic levels may impact the overall drought resilience of small freshwater ecosystems in a more complex way than expected.

Published
2022
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4. Come Rain, Come Shine: Peatland Carbon Dynamics Shift Under Extreme Precipitation

Author

Janna M. Barel, Vincent Moulia, Samuel Hamard, Anna Sytiuk, and Vincent E. J. Jassey

Subjects
resistance, resilience, dissolved organic carbon, decomposition, water table fluctuation, rewetting, Environmental sciences, GE1-350
Abstract

Precipitation patterns are becoming increasingly extreme, particularly at northern latitudes. Current climate models predict that this trend will continue in the future. While droughts have been repeatedly studied in many ecosystems over the last decades, the consequences of increasingly intense, but less frequent rainfall events, on carbon (C) cycling are not well understood. At northern latitudes, peatlands store one third of the terrestrial carbon and their functioning is highly dependent on water. Shifts in rainfall regimes could disrupt peatland C dynamics and speed-up the rates of C loss. How will these immense stocks of C be able to withstand and recover from extreme rainfall? We tested the resistance and resilience effects of extreme precipitation regimes on peatland carbon dioxide (CO2) and methane (CH4) fluxes, pore water dissolved organic carbon (DOC) and litter decomposition rates by exposing intact peat cores to extreme, spring-time rainfall patterns in a controlled mesocosm experiment. We find that more intense but less frequent rainfall destabilized water table dynamics, with cascading effects on peatland C fluxes. Decomposition and respiration rates increased with a deeper mean water table depth (WTD) and larger WTD fluctuations. We observed similar patterns for CO2 uptake, which were likely mediated by improved vascular plant performance. After a three-week recovery period, CO2 fluxes still displayed responses to the earlier WTD dynamics, suggesting lagged effects of precipitation regime shifts. Furthermore, we found that CH4 emissions decreased with deeper mean WTD, but this showed a high resilience once WTD dynamics stabilised. Not only do our results illustrate that shifting rainfall patterns translate in altered WTD dynamics and, consequentially, influence C fluxes, they also demonstrate that exposure to altered rainfall early in the growing season can have lasting effects on CO2 exchange. Even though the increased CO2 assimilation under extreme precipitation patterns signals peatland resistance under changing climatic conditions, it may instead mark the onset of vascular plant encroachment and the associated C loss.

Published
2021
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5. Testate Amoeba Functional Traits and Their Use in Paleoecology

Author

Katarzyna Marcisz, Vincent E. J. Jassey, Anush Kosakyan, Valentyna Krashevska, Daniel J. G. Lahr, Enrique Lara, Łukasz Lamentowicz, Mariusz Lamentowicz, Andrew Macumber, Yuri Mazei, Edward A. D. Mitchell, Nawaf A. Nasser, R. Timothy Patterson, Helen M. Roe, David Singer, Andrey N. Tsyganov, and Bertrand Fournier

Subjects
protists, functional traits, morphological traits, ecology, peatlands, lakes, Evolution, QH359-425, Ecology, QH540-549.5
Abstract

This review provides a synthesis of current knowledge on the morphological and functional traits of testate amoebae, a polyphyletic group of protists commonly used as proxies of past hydrological changes in paleoecological investigations from peatland, lake sediment and soil archives. A trait-based approach to understanding testate amoebae ecology and paleoecology has gained in popularity in recent years, with research showing that morphological characteristics provide complementary information to the commonly used environmental inferences based on testate amoeba (morpho-)species data. We provide a broad overview of testate amoeba morphological and functional traits and trait-environment relationships in the context of ecology, evolution, genetics, biogeography, and paleoecology. As examples we report upon previous ecological and paleoecological studies that used trait-based approaches, and describe key testate amoebae traits that can be used to improve the interpretation of environmental studies. We also highlight knowledge gaps and speculate on potential future directions for the application of trait-based approaches in testate amoeba research.

Published
2020
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6. Taxonomic and functional turnover are decoupled in European peat bogs

Author

Bjorn J. M. Robroek, Vincent E. J. Jassey, Richard J. Payne, Magalí Martí, Luca Bragazza, Albert Bleeker, Alexandre Buttler, Simon J. M. Caporn, Nancy B. Dise, Jens Kattge, Katarzyna Zając, Bo H. Svensson, Jasper van Ruijven, and Jos T. A. Verhoeven

Subjects
Science
Abstract

Peatland plant communities are expected to be affected by environmental change, though how assemblages respond is not fully understood. Here, Robroek et al. show that peatland species occur in two distinct clusters, and functional identity and redundancy was maintained under taxonomic turnover.

Published
2017
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7. Effects of Sphagnum Leachate on Competitive Sphagnum Microbiome Depend on Species and Time

Author

Samuel Hamard, Bjorn J. M. Robroek, Pierre-Marie Allard, Constant Signarbieux, Shuaizhen Zhou, Tongchai Saesong, Flore de Baaker, Alexandre Buttler, Geneviève Chiapusio, Jean-Luc Wolfender, Luca Bragazza, and Vincent E. J. Jassey

Subjects
allelopathy and allelochemicals, metabolomics, microbial networks, microbial respiration and biomass, peatland, plant competition, Microbiology, QR1-502
Abstract

Plant specialized metabolites play an important role in soil carbon (C) and nutrient fluxes. Through anti-microbial effects, they can modulate microbial assemblages and associated microbial-driven processes, such as nutrient cycling, so to positively or negatively cascade on plant fitness. As such, plant specialized metabolites can be used as a tool to supplant competitors. These compounds are little studied in bryophytes. This is especially notable in peatlands where Sphagnum mosses can dominate the vegetation and show strong interspecific competition. Sphagnum mosses form carpets where diverse microbial communities live and play a crucial role in Sphagnum fitness by regulating C and nutrient cycling. Here, by means of a microcosm experiment, we assessed to what extent moss metabolites of two Sphagnum species (S. fallax and S. divinum) modulate the competitive Sphagnum microbiome, with particular focus on microbial respiration. Using a reciprocal leachate experiment, we found that interactions between Sphagnum leachates and microbiome are species-specific. We show that both Sphagnum leachates differed in compound richness and compound relative abundance, especially sphagnum acid derivates, and that they include microbial-related metabolites. The addition of S. divinum leachate on the S. fallax microbiome immediately reduced microbial respiration (−95%). Prolonged exposition of S. fallax microbiome to S. divinum leachate destabilized the food web structure due to a modulation of microbial abundance. In particular, leachate addition decreased the biomass of testate amoebae and rotifers but increased that of ciliates. These changes did not influence microbial CO2 respiration, suggesting that the structural plasticity of the food web leads to its functional resistance through the replacement of species that are functionally redundant. In contrast, S. fallax leachate neither affected S. divinum microbial respiration, nor microbial biomass. We, however, found that S. fallax leachate addition stabilized the food web structure associated to S. divinum by changing trophic interactions among species. The differences in allelopathic effects between both Sphagnum leachates might impact their competitiveness and affect species distribution at local scale. Our study further paves the way to better understand the role of moss and microbial specialized metabolites in peatland C dynamics.

Published
2019
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8. Diverse fen plant communities enhance carbon-related multifunctionality, but do not mitigate negative effects of drought

Author

Bjorn J. M. Robroek, Vincent E. J. Jassey, Boudewijn Beltman, and Mariet M. Hefting

Subjects
carbon cycling, ecosystem functions, global change, multiple functions, plant functional types, wetlands, Science
Abstract

Global change, like droughts, can destabilize the carbon sink function of peatlands, either directly or indirectly through changes in plant community composition. While the effects of drought and plant community composition on individual carbon (C) related processes are well understood, their effect on multiple C-related processes simultaneously—multifunctionality—is poorly known. We studied the effect of drought on four C-related processes (net and gross CO2 exchange, methane fluxes, and dissolved organic carbon content) in a plant removal experiment. Plant functional type (PFT) removal (graminoids, herbs, Polytrichum spp., incl. combinations) negatively affected multifunctionality; most markedly when all PFTs were removed. Our results corroborate a negative drought effect on C-related multifunctionality. Drought reduced multifunctionality, and this reduction was again largest when all PFTs were removed. Our data further indicate that much of these negative drought effects were carried over and maintained from the initial removal treatment. These results suggest that while a high diversity in plant functional types is associated to high C-related multifunctionality, plant community assembly does not drive the ability of peatlands to withstand the negative impacts of drought on multifunctionality. Hence, to safeguard the carbon cycling function in intact peatlands, the effects of climate change on the functional composition of the peatland plant community needs to be minimized.

Published
2017
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9. Leaf metabolic traits reveal hidden dimensions of plant form and function

Author

Tom W. N. Walker, Franziska Schrodt, Pierre-Marie Allard, Emmanuel Defossez, Vincent E. J. Jassey, Meredith C. Schuman, Jake M. Alexander, Oliver Baines, Virginie Baldy, Richard D. Bardgett, Pol Capdevila, Phyllis D. Coley, Nicole M. van Dam, Bruno David, Patrice Descombes, Maria-Jose Endara, Catherine Fernandez, Dale Forrister, Albert Gargallo-Garriga, Gaёtan Gauser, Sue Marr, Steffen Neumann, Loïc Pellissier, Kristian Peters, Sergio Rasmann, Ute Roessner, Roberto Salguero-Gómez, Jordi Sardans, Wolfram Weckwerth, Jean-Luc Wolfender, and Josep Peñuelas

Abstract

SummaryThe plant metabolome encompasses the biochemical mechanisms through which evolutionary and ecological processes shape plant form and function1,2. However, while the metabolome should thus be an important component of plant life-history variation3, we know little about how it varies across the plant kingdom. Here, we use the plant functional trait concept4– a powerful framework for describing plant form and function5–7– to interpret leaf metabolome variation among 457 tropical and 339 temperate plant species. Distilling metabolite chemistry into five discriminant metabolic functional traits reveals that plants vary along two major axes of leaf metabolic specialization – a leaf chemical defense spectrum and an expression of leaf longevity. These axes are qualitatively consistent for tropical and temperate species, with many trait combinations being viable. However, axes of leaf metabolic specialization vary orthogonally to life-history strategies described by widely used functional traits5–7, while being at least equally important to them. Our findings question classical trait6and plant defense8theory that predicts relationships between the leaf chemical phenotype, plant productivity, and pace of life. Moreover, we show that metabolic functional traits describe unique dimensions of plant life-history variation that are complementary to, and independent from, those captured by existing plant functional traits.

Published
2023
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10. Biochemical traits enhance the trait concept in Sphagnum ecology

Author

Anna Sytiuk, Regis Céréghino, Samuel Hamard, Frédéric Delarue, Ellen Dorrepaal, Martin Küttim, Mariusz Lamentowicz, Bertrand Pourrut, Bjorn J. M. Robroek, Eeva‐Stiina Tuittila, Vincent E. J. Jassey, Laboratoire Ecologie Fonctionnelle et Environnement (LEFE), Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT), Milieux Environnementaux, Transferts et Interactions dans les hydrosystèmes et les Sols (METIS), École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Umeå University, Tallinn University, Adam Mickiewicz University in Poznań (UAM), Radboud University [Nijmegen], University of Southampton, and ANR-17-CE01-0007,MIXOPEAT,Repenser le cycle du carbone des tourbières : identifier le rôle des protistes mixotrophes dans la pompe à carbone biologique(2017)

Subjects
Sphagnum, climate change, bryophytes, [SDV]Life Sciences [q-bio], antioxidant enzyme activities, Aquatic Ecology, Ecology, Evolution, Behavior and Systematics, peatlands, metabolites
Abstract

International audience; Sphagnum mosses are key to northern peatland carbon sequestration. They have a range of morphological and anatomical characteristics that allow them to cope with environmental stress. Sphagnum also produces a plethora of biochemicals that may prevent stress-induced cell-damage. However, the linkages between Sphagnum anatomical, morphological and biochemical traits (i.e. metabolites, pigments and antioxidant enzyme activities) are poorly known, neither are their joint responses to environmental change. Here, we quantify and link an array of Sphagnum anatomical, morphological and biochemical traits in five Sphagnum-dominated peatlands distributed along a latitudinal gradient in Europe, covering a range of regional and local environmental conditions. Sphagnum morphological and anatomical traits were intrinsically linked to Sphagnum metabolites and enzyme activities, and these relationships were driven by shared responses to local and regional environmental factors. More particularly, we found that Sphagnum traits can be grouped into four clusters related to growth, biomass, defense and water stress tolerance. We used regional and local environmental conditions data to further show that biochemicals and their specific linkages with some morphological traits describe dimensions of physiology not captured by anatomical and morphological traits alone. These results suggest that Sphagnum morphology and function is rooted in the metabolome, and that incorporating biochemicals into the functional trait space concept can enhance our mechanistic understanding and predictive power in Sphagnum ecology.

Published
2022
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11. Linkages between Sphagnum metabolites and peatland <scp> CO 2 </scp> uptake are sensitive to seasonality in warming trends

Author

Anna Sytiuk, Samuel Hamard, Régis Céréghino, Ellen Dorrepaal, Honorine Geissel, Martin Küttim, Mariusz Lamentowicz, Eeva Stiina Tuittila, Vincent E. J. Jassey, Laboratoire Ecologie Fonctionnelle et Environnement (LEFE), Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT), and ANR-17-CE01-0007,MIXOPEAT,Repenser le cycle du carbone des tourbières : identifier le rôle des protistes mixotrophes dans la pompe à carbone biologique(2017)

Subjects
Climate Research, Physiology, seasonality, [SDE.MCG]Environmental Sciences/Global Changes, Plant Science, carbon cycle climate change climate feedback intraspecific variability phenotypic plasticity plant metabolism seasonality Sphagnum, phenotypic plasticity, Klimatforskning, plant metabolism, climate change, Sphagnum, carbon cycle, climate feedback, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, intraspecific variability
Abstract

International audience; Plants produce a wide diversity of metabolites. Yet, our understanding of how shifts in plant metabolites as a response to climate change feedback on ecosystem processes remains scarce. Here, we test to what extent climate warming shifts the seasonality of metabolites produced by Sphagnum mosses, and what are the consequences of these shifts for peatland C uptake. We used a reciprocal transplant experiment along a climate gradient in Europe to simulate climate change. We evaluated the responses of primary and secondary metabolites in five Sphagnum species and related their responses to gross ecosystem productivity (GEP). When transplanted to a warmer climate, Sphagnum species showed consistent responses to warming, with an upregulation of either their primary or secondary metabolite according to seasons. Moreover, these shifts were correlated to changes in GEP, especially in spring and autumn. Our results indicate that the Sphagnum metabolome is very plastic and sensitive to warming. We also show that warming-induced changes in the seasonality of Sphagnum metabolites have consequences on peatland GEP. Our findings demonstrate the capacity for plant metabolic plasticity to impact ecosystem C processes and reveal a further mechanism through which Sphagnum could shape peatland responses to climate change.

Published
2022
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12. Linkages between Sphagnum metabolites and peatland CO

Author

Anna, Sytiuk, Samuel, Hamard, Régis, Céréghino, Ellen, Dorrepaal, Honorine, Geissel, Martin, Küttim, Mariusz, Lamentowicz, Eeva Stiina, Tuittila, and Vincent E J, Jassey

Abstract

Plants produce a wide diversity of metabolites. Yet, our understanding of how shifts in plant metabolites as a response to climate change feedback on ecosystem processes remains scarce. Here, we test to what extent climate warming shifts the seasonality of metabolites produced by Sphagnum mosses, and what are the consequences of these shifts for peatland C uptake. We used a reciprocal transplant experiment along a climate gradient in Europe to simulate climate change. We evaluated the responses of primary and secondary metabolites in five Sphagnum species and related their responses to gross ecosystem productivity (GEP). When transplanted to a warmer climate, Sphagnum species showed consistent responses to warming, with an upregulation of either their primary or secondary metabolite according to seasons. Moreover, these shifts were correlated to changes in GEP, especially in spring and autumn. Our results indicate that the Sphagnum metabolome is very plastic and sensitive to warming. We also show that warming-induced changes in the seasonality of Sphagnum metabolites have consequences on peatland GEP. Our findings demonstrate the capacity for plant metabolic plasticity to impact ecosystem C processes and reveal a further mechanism through which Sphagnum could shape peatland responses to climate change.

Published
2022

13. Interactive effects of metals and carbon nanotubes in a microcosm agrosystem

Author

Mathieu, Leroy, Benjamin, Pey, Vincent E J, Jassey, Clarisse, Liné, Arnaud, Elger, Anne, Probst, Emmanuel, Flahaut, Jérôme, Silvestre, Camille, Larue, Centre National de la Recherche Scientifique - CNRS (FRANCE), Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE), Université Toulouse III - Paul Sabatier - UT3 (FRANCE), Laboratoire Ecologie Fonctionnelle et Environnement (LEFE), Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT), Centre interuniversitaire de recherche et d'ingenierie des matériaux (CIRIMAT), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées, and Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP)

Subjects
Environmental Engineering, Health, Toxicology and Mutagenesis, Matériaux, [SPI.MAT]Engineering Sciences [physics]/Materials, Soil, Animals, Soil Pollutants, Environmental Chemistry, Oligochaeta, multiple stress, Waste Management and Disposal, Risk assessment, [SDV.EE]Life Sciences [q-bio]/Ecology, environment, Ecologie, Environnement, Toxicity, Nanotubes, Carbon, risk assessment, toxicity, Multiple stress, Pollution, Transfer, cocktail contaminants, Metals, Cocktail contaminants, [SDV.TOX.ECO]Life Sciences [q-bio]/Toxicology/Ecotoxicology, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, transfer
Abstract

International audience; Agricultural soils are exposed to multiple contaminants through the use of agrochemicals or sewage sludge, introducing metals, nanomaterials and others. Among nanomaterials, carbon nanotubes (CNTs) are known for their large surface area and adsorption capabilities, possibly modifying other element behavior. However, to date, very little is known about the impacts of such interactions in agrosystems. In this study, we aimed at understanding the transfer and toxicity of contaminants (Cd, Pb, Zn and CNTs) in microcosms including native soil bacteria, earthworms and lettuce. After a 6 week exposure, no effect of the addition of CNTs to metal contaminated soils was detected on bacterial concentration or earthworm growth. However, in lettuce, an interactive effect between CNTs and metals was highlighted: in the soil containing the highest metal concentrations the addition of 0.1 mg kg−1 CNTs led to a biomass loss (−22%) and a flavonoid concentration increase (+27%). In parallel, the addition of CNTs led to differential impacts on elemental uptake in lettuce leaves possibly related to the soil organic matter content. For earthworms, the addition of 10 mg kg−1 CNTs resulted in an increased body elemental transfer in the soil with the higher organic matter content (Pb: + 34% and Zn: + 25%).

Published
2022
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14. In situ resistance, not immigration, supports invertebrate community resilience to drought intensification in a Neotropical ecosystem

Author

Joséphine Leflaive, Nicholas A. C. Marino, Vinicius F. Farjalla, Thibaut Rota, Diane S. Srivastava, Bruno Corbara, Régis Céréghino, Vincent E. J. Jassey, Céline Leroy, Jean-François Carrias, Arthur Compin, Camille Bonhomme, Universidade Federal do Estado do Rio de Janeiro (UNIRIO), Botanique et Modélisation de l'Architecture des Plantes et des Végétations (UMR AMAP), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Laboratoire Ecologie Fonctionnelle et Environnement (LEFE), Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT), Laboratoire Microorganismes : Génome et Environnement (LMGE), Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA), University of British Columbia (UBC), Ecologie des forêts de Guyane (UMR ECOFOG), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-AgroParisTech-Université de Guyane (UG)-Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), EC2CO‐Biohefect, ANR-18-CE02-0015,RESILIENCE,Démêler les rôles des traits biologiques et de la dynamique des métacommunautés sur la résilience multifonctionnelle des écosystèmes néotropicaux(2018), ANR-10-LABX-0025,CEBA,CEnter of the study of Biodiversity in Amazonia(2010), Laboratoire Ecologie Fonctionnelle et Environnement (ECOLAB), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), and Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)

Subjects
0106 biological sciences, Metacommunity, media_common.quotation_subject, Resistance, Climate change, Community, Biology, [SDV.BID.SPT]Life Sciences [q-bio]/Biodiversity/Systematics, Phylogenetics and taxonomy, 010603 evolutionary biology, 01 natural sciences, [SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, Animals, Ecosystem, Freshwater ecosystems Functional traits, Ecology, Evolution, Behavior and Systematics, media_common, Community resilience, Drought, Resilience, Resistance (ecology), Ecology, 010604 marine biology & hydrobiology, fungi, Community structure, food and beverages, Emigration and Immigration, [SDV.BV.BOT]Life Sciences [q-bio]/Vegetal Biology/Botanics, 15. Life on land, Invertebrates, Droughts, 13. Climate action, Biological dispersal, Animal Science and Zoology, Psychological resilience, [SDE.BE]Environmental Sciences/Biodiversity and Ecology
Abstract

International audience; While future climate scenarios predict declines in precipitations in many regions of the world, little is known of the mechanisms underlying community resilience to prolonged dry seasons, especially in ‘naïve’ Neotropical rainforests. Predictions of community resilience to intensifying drought are complicated by the fact that the underlying mechanisms are mediated by species' tolerance and resistance traits, as well as rescue through dispersal from source patches.We examined the contribution of in situ tolerance‐resistance and immigration to community resilience, following drought events that ranged from the ambient norm to IPCC scenarios and extreme events. We used rainshelters above rainwater‐filled bromeliads of French Guiana to emulate a gradient of drought intensity (from 1 to 3.6 times the current number of consecutive days without rainfall), and we analysed the post‐drought dynamics of the taxonomic and functional community structure of aquatic invertebrates to these treatments when immigration is excluded (by netting bromeliads) or permitted (no nets). Drought intensity negatively affected invertebrate community resistance, but had a positive influence on community recovery during the post‐drought phase. After droughts of 1 to 1.4 times the current intensities, the overall invertebrate abundance recovered within invertebrate life cycle durations (up to 2 months). Shifts in taxonomic composition were more important after longer droughts, but overall, community composition showed recovery towards baseline states. The non‐random patterns of changes in functional community structure indicated that deterministic processes like environmental filtering of traits drive community re‐assembly patterns after a drought event. Community resilience mostly relied on in situ tolerance‐resistance traits. A rescue effect of immigration after a drought event was weak and mostly apparent under extreme droughts.Under climate change scenarios of drought intensification in Neotropical regions, community and ecosystem resilience could primarily depend on the persistence of suitable habitats and on the resistance traits of species, while metacommunity dynamics could make a minor contribution to ecosystem recovery. Climate change adaptation should thus aim at identifying and preserving local conditions that foster in situ resistance and the buffering effects of habitat features.

Published
2020
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15. Functional Traits 2.0: The power of the metabolome for ecology

Author

Tom W. N. Walker, Jake M. Alexander, Pierre‐Marie Allard, Oliver Baines, Virginie Baldy, Richard D. Bardgett, Pol Capdevila, Phyllis D. Coley, Bruno David, Emmanuel Defossez, María‐José Endara, Madeleine Ernst, Catherine Fernandez, Dale Forrister, Albert Gargallo‐Garriga, Vincent E. J. Jassey, Sue Marr, Steffen Neumann, Loïc Pellissier, Josep Peñuelas, Kristian Peters, Sergio Rasmann, Ute Roessner, Jordi Sardans, Franziska Schrodt, Meredith C. Schuman, Abrianna Soule, Henriette Uthe, Wolfram Weckwerth, Jean‐Luc Wolfender, Nicole M. Dam, Roberto Salguero‐Gómez, Institut méditerranéen de biodiversité et d'écologie marine et continentale (IMBE), Avignon Université (AU)-Aix Marseille Université (AMU)-Institut de recherche pour le développement [IRD] : UMR237-Centre National de la Recherche Scientifique (CNRS), Leibniz Institute of Plant Biochemistry (IPB), German Centre for Integrative Biodiversity Research (iDiv), and ANR-17-CE01-0007,MIXOPEAT,Repenser le cycle du carbone des tourbières : identifier le rôle des protistes mixotrophes dans la pompe à carbone biologique(2017)

Subjects
0106 biological sciences, 2. Zero hunger, 0303 health sciences, Ecology, ecophysiology, fitness, functional traits, life history, metabolite, metabolomics, plasticity, trade-offs, Plant Science, 15. Life on land, 010603 evolutionary biology, 01 natural sciences, 03 medical and health sciences, 13. Climate action, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Ecology, Evolution, Behavior and Systematics, 030304 developmental biology
Abstract

1. A major aim of ecology is to upscale attributes of individuals to understand processes at population, community and ecosystem scales. Such attributes are typically described using functional traits, that is, standardised characteristics that impact fitness via effects on survival, growth and/or reproduction. However, commonly used functional traits (e.g. wood density, SLA) are becoming increasingly criticized for not being truly mechanistic and for being questionable predictors of ecological processes. 2. This Special Feature reviews and studies how the metabolome (i.e. the thousands of unique metabolites that underpin physiology) can enhance trait-based ecology and our understanding of plant and ecosystem functioning. 3. In this Editorial, we explore how the metabolome relates to plant functional traits, with reference to life-history trade-offs governing fitness between generations and plasticity shaping fitness within generations. We also identify solutions to challenges of acquiring, interpreting and contextualising metabolome data, and propose a roadmap for integrating the metabolome into ecology. 4. We next summarise the seven studies composing the Special Feature, which use the metabolome to examine mechanisms behind plant community assembly, plant-organismal interactions and effects of plants and soil micro-organisms on ecosystem processes. 5. Synthesis. We demonstrate the potential of the metabolome to improve mechanistic and predictive power in ecology by providing a high-resolution coupling between physiology and fitness. However, applying metabolomics to ecological questions is currently limited by a lack of conceptual, technical and data frameworks, which needs to be overcome to realise the full potential of the metabolome for ecology. ISSN:0022-0477

Published
2022
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16. Author response for 'Functional Traits 2.0: The power of the metabolome for ecology'

Author

null Tom W. N. Walker, null Jake M. Alexander, null Pierre‐Marie Allard, null Oliver Baines, null Virginie Baldy, null Richard D. Bardgett, null Pol Capdevila, null Phyllis D. Coley, null Bruno David, null Emmanuel Defossez, null María‐José Endara, null Madeleine Ernst, null Catherine Fernandez, null Dale Forrister, null Albert Gargallo‐Garriga, null Vincent E. J. Jassey, null Sue Marr, null Steffen Neumann, null Loïc Pellissier, null Josep Peñuelas, null Kristian Peters, null Sergio Rasmann, null Ute Roessner, null Jordi Sardans, null Franziska Schrodt, null Meredith C. Schuman, null Abrianna Soule, null Henriette Uthe, null Wolfram Weckwerth, null Jean‐Luc Wolfender, null Nicole M. Dam, and null Roberto Salguero‐Gómez

Published
2021
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17. Contribution of soil algae to the global carbon cycle

Author

Vincent E. J. Jassey, Romain Walcker, Paul Kardol, Stefan Geisen, Thierry Heger, Mariusz Lamentowicz, Samuel Hamard, Enrique Lara, Terrestrial Ecology (TE), Laboratoire Ecologie Fonctionnelle et Environnement (LEFE), Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT), Swedish University of Agricultural Sciences (SLU), Wageningen University and Research [Wageningen] (WUR), Netherlands Institute of Ecology (NIOO-KNAW), University of Applied Sciences of Western Switzerland, Adam Mickiewicz University in Poznań (UAM), and ANR-17-CE01-0007,MIXOPEAT,Repenser le cycle du carbone des tourbières : identifier le rôle des protistes mixotrophes dans la pompe à carbone biologique(2017)

Subjects
Physiology, soil C cycle, [SDE.MCG]Environmental Sciences/Global Changes, net primary productivity (NPP), photoautotrophs, Plant Science, Plan_S-Compliant_NO, Plants, PE&RC, Carbon, Carbon Cycle, soil carbon (C) cycle, Soil, international, microbial photosynthesis, soil microbiome, net primary productivity, Laboratory of Nematology, Laboratorium voor Nematologie, biogeography, Ecosystem
Abstract

International audience; Soil photoautotrophic prokaryotes and micro-eukaryotes – known as soil algae – are, together with heterotrophic microorganisms, a constitutive part of the microbiome in surface soils. Similar to plants, they fix atmospheric carbon (C) through photosynthesis for their own growth, yet their contribution to global and regional biogeochemical C cycling still remains quantitatively elusive.Here, we compiled an extensive dataset on soil algae to generate a better understanding of their distribution across biomes and predict their productivity at a global scale by means of machine learning modelling.We found that, on average, (5.5 ± 3.4) × 106 algae inhabit each gram of surface soil. Soil algal abundance especially peaked in acidic, moist and vegetated soils. We estimate that, globally, soil algae take up around 3.6 Pg C per year, which corresponds to c. 6% of the net primary production of terrestrial vegetation.We demonstrate that the C fixed by soil algae is crucial to the global C cycle and should be integrated into land-based efforts to mitigate C emissions.

Published
2021
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18. Peatland microhabitat heterogeneity drives phototrophic microbe distribution and photosynthetic activity

Author

Régis Céréghino, Martin Küttim, Samuel Hamard, Vincent E. J. Jassey, Laboratoire Ecologie Fonctionnelle et Environnement (ECOLAB), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Ecologie Fonctionnelle et Environnement (LEFE), Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT), and ANR-17-CE01-0007,MIXOPEAT,Repenser le cycle du carbone des tourbières : identifier le rôle des protistes mixotrophes dans la pompe à carbone biologique(2017)

Subjects
0106 biological sciences, Microbial diversity, Peat, Algae, Peatland, Soil carbon uptake, Forests, 010603 evolutionary biology, 01 natural sciences, Microbiology, Sphagnum, [SDV.MP.PRO]Life Sciences [q-bio]/Microbiology and Parasitology/Protistology, Soil, [SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, Sphagnopsida, Dominance (ecology), Photosynthesis, Ecology, Evolution, Behavior and Systematics, Soil Microbiology, ComputingMilieux_MISCELLANEOUS, Abiotic component, Biomass (ecology), biology, Phototroph, Ecology, 010604 marine biology & hydrobiology, Soil carbon, Carbon cycle, Phototrophs, 15. Life on land, biology.organism_classification, Light intensity, 13. Climate action, Metabarcoding, Primary productivity
Abstract

Phototrophic microbes are widespread in soils, but their contribution to soil carbon (C) uptake remains underexplored in most terrestrial systems, including C-accreting systems such as peatlands. Here, by means of metabarcoding and ecophysiological measurements, we examined how microbial photosynthesis and its biotic (e.g., phototrophic community structure, biomass) and abiotic drivers (e.g., Sphagnum moisture, light intensity) vary across peatland microhabitats. Using a natural gradient of microhabitat conditions from pool to forest, we show that the structure of phototrophic microbial communities shifted from a dominance of eukaryotes in pools to prokaryotes in forests. We identified five groups of co-occurring phototrophic operational taxonomic units with specific environmental preferences across the gradient. Along with such structural changes, we found that microbial C uptake was the highest in the driest and shadiest microhabitats. This study renews and improves current views on phototrophic microbes in peatlands, as the contribution of microbial photosynthesis to peatland C uptake has essentially been studied in wet microhabitats.

Published
2021
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19. Come Rain, Come Shine: Peatland Carbon Dynamics Shift Under Extreme Precipitation

Author

Anna Sytiuk, Vincent Moulia, Janna M. Barel, Samuel Hamard, Vincent E. J. Jassey, Laboratoire Ecologie Fonctionnelle et Environnement (ECOLAB), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Biotechnologie de l'Environnement [Narbonne] (LBE), Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Gestion de l'Eau, Acteurs, Usages (UMR G-EAU), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut de Recherche pour le Développement (IRD)-AgroParisTech-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Fondation pour la Recherche sur la Biodiversite which acted in cooperation with the French Agency for Biodiversity (AFB), and its partners (FRB-www.fondationbiodiversite.fr), ANR-17-CE01-0007,MIXOPEAT,Repenser le cycle du carbone des tourbières : identifier le rôle des protistes mixotrophes dans la pompe à carbone biologique(2017), Laboratoire Ecologie Fonctionnelle et Environnement (LEFE), Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT), Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut Agro - Montpellier SupAgro, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), and Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut de Recherche pour le Développement (IRD)-AgroParisTech-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut Agro - Montpellier SupAgro

Subjects
0106 biological sciences, Peat, 010504 meteorology & atmospheric sciences, Water table, Growing season, Atmospheric sciences, 010603 evolutionary biology, 01 natural sciences, Mesocosm, resistance, chemistry.chemical_compound, Dissolved organic carbon, GE1-350, Ecosystem, Precipitation, resilience, 0105 earth and related environmental sciences, General Environmental Science, [SDV.EE]Life Sciences [q-bio]/Ecology, environment, decomposition, rewetting, methane, water table fluctuation, carbon dioxide, 15. Life on land, dissolved organic carbon, Environmental sciences, chemistry, 13. Climate action, Carbon dioxide, Environmental science
Abstract

Precipitation patterns are becoming increasingly extreme, particularly at northern latitudes. Current climate models predict that this trend will continue in the future. While droughts have been repeatedly studied in many ecosystems over the last decades, the consequences of increasingly intense, but less frequent rainfall events, on carbon (C) cycling are not well understood. At northern latitudes, peatlands store one third of the terrestrial carbon and their functioning is highly dependent on water. Shifts in rainfall regimes could disrupt peatland C dynamics and speed-up the rates of C loss. How will these immense stocks of C be able to withstand and recover from extreme rainfall? We tested the resistance and resilience effects of extreme precipitation regimes on peatland carbon dioxide (CO2) and methane (CH4) fluxes, pore water dissolved organic carbon (DOC) and litter decomposition rates by exposing intact peat cores to extreme, spring-time rainfall patterns in a controlled mesocosm experiment. We find that more intense but less frequent rainfall destabilized water table dynamics, with cascading effects on peatland C fluxes. Decomposition and respiration rates increased with a deeper mean water table depth (WTD) and larger WTD fluctuations. We observed similar patterns for CO2 uptake, which were likely mediated by improved vascular plant performance. After a three-week recovery period, CO2 fluxes still displayed responses to the earlier WTD dynamics, suggesting lagged effects of precipitation regime shifts. Furthermore, we found that CH4 emissions decreased with deeper mean WTD, but this showed a high resilience once WTD dynamics stabilised. Not only do our results illustrate that shifting rainfall patterns translate in altered WTD dynamics and, consequentially, influence C fluxes, they also demonstrate that exposure to altered rainfall early in the growing season can have lasting effects on CO2 exchange. Even though the increased CO2 assimilation under extreme precipitation patterns signals peatland resistance under changing climatic conditions, it may instead mark the onset of vascular plant encroachment and the associated C loss.

Published
2021
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20. When water runs dry — peatland C dynamic under extreme droughts

Author

Vincent E. J. Jassey, Janna M. Barel, and Mariusz Lamentowicz

Subjects
Hydrology, Peat, Environmental science
Abstract

Ecosystems are increasingly exposed to climatic extremes, such as drought and extreme rainfall patterns. Recent studies evidenced the strong variability in ecosystem’s response to droughts, raising the issue of non-linear responses in ecosystem’s carbon (C) dynamic. The conundrum is what causes C fluxes to shift in response to drought, and most importantly, does such extreme events have lasting effects? Here, we will synthesize the results from three different studies testing the effect of droughts and/or extreme rainfall patterns on peatland CO2 fluxes.In a first experiment, we tested the resistance and resilience effects of extreme rainfall patterns on peatland C fluxes in a mesocosm experiment. We found that increasingly intense but less frequent rainfall, with longer intermediate dry periods, destabilises water table dynamic, with cascading effects on peatland C fluxes. Yet, peatland C dynamics might be more resilient than expected as vascular plants may fulfil a compensatory role by taking up more C. Moreover, CO2 fluxes displayed lasting influence of extreme rainfall after restoration of the water table dynamics.In a second experiment, we manipulated the water table depth in the field and generated a gradient spanning from -5 to -60 cm. We found that substantial changes in peatland CO2 respiration occurred when the water level fell below a critical point of -24 cm. Around that apparently critical water level, we showed that plant and fungal communities were suddenly altered and raised CO2 respiration rates.In the last experiment, we tested the combined effect of prolonged drought and warming on the C uptake of two Sphagnum species. We found that the effect of climate warming on Sphagnum community photosynthesis toggles from positive to negative as the peatland goes from rainy to dry periods during summer. We further found that mechanisms of compensation among the dominant Sphagnum species stabilized the average C uptake of the Sphagnum community over the growing season.As a corollary, our results show that extreme climatic events induce functional transitions in peatland C dynamics. These functional transitions further depends on the phenotypic plasticity among plant and microbial species as well as on the evenness of specific functional groups that modulate the effects of droughts on peatland C dynamic.

Published
2021
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21. Disentangling the direct and indirect effects of agricultural runoff on freshwater ecosystems subject to global warming: A microcosm study

Author

Sabine Hilt, Mechthild Schmitt-Jansen, Arthur Compin, Vinita Vijayaraj, Camille Courcoul, Arnaud Elger, Stéphanie Boulêtreau, Elisabeth M. Gross, Bastian H. Polst, Joséphine Leflaive, Vincent E. J. Jassey, Joey L. Allen, Jessica Ferriol, Martin Laviale, Herwig Stibor, Laboratoire Ecologie Fonctionnelle et Environnement (ECOLAB), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Interdisciplinaire des Environnements Continentaux (LIEC), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Terre et Environnement de Lorraine (OTELo), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)-Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Helmholtz Zentrum für Umweltforschung = Helmholtz Centre for Environmental Research (UFZ), Ludwig Maximilian University [Munich] (LMU), ANR-17-CE32-0013,CLIMSHIFT,Changement de régime dans des écosystèmes d'eau douce exposés à des stress combinés de température, engrais et pesticides(2017), Laboratoire Ecologie Fonctionnelle et Environnement (LEFE), Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Terre et Environnement de Lorraine (OTELo), and Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Environmental Engineering, agricultural run-off, [SDE.MCG]Environmental Sciences/Global Changes, 0208 environmental biotechnology, Lymnaea stagnalis, 02 engineering and technology, 010501 environmental sciences, global warming, 01 natural sciences, Freshwater ecosystem, biotic interactions, [SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, Phytoplankton, Animals, Periphyton, Multiple stressors, Waste Management and Disposal, Ecosystem, 0105 earth and related environmental sciences, Water Science and Technology, Civil and Structural Engineering, Trophic level, aquatic ecosystems, Primary producers, biology, Ecology, Ecological Modeling, Aquatic ecosystem, Agriculture, biology.organism_classification, Pollution, 6. Clean water, 020801 environmental engineering, Lakes, 13. Climate action, Environmental science, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Microcosm
Abstract

International audience; Aquatic ecosystems are exposed to multiple stressors such as agricultural run-off (ARO) and climate-change related increase of temperature. We aimed to determine how ARO and the frequency of its input can affect shallow lake ecosystems through direct and indirect effects on primary producers and primary consumers, and whether warming can mitigate or reinforce the impact of ARO. We performed a set of microcosm experiments simulating ARO using a cocktail of three organic pesticides (terbuthylazine, tebuconazole, pirimicarb), copper and nitrate. Two experiments were performed to determine the direct effect of ARO on primary producers (submerged macrophytes, periphyton and phytoplankton) and on the grazing snail Lymnaea stagnalis, respectively. Three different ARO concentrations added as single doses or as multiple pulses at two different temperatures (22°C and 26°C) were applied. In a third experiment, primary producers and consumers were exposed together to allow trophic interactions. When functional groups were exposed alone, ARO had a direct positive effect on phytoplankton and a strong negative effect on L. stagnalis. When exposed together, primary producer responses were contrasting, as the negative effect of ARO on grazers led to an indirect positive effect on periphyton. Periphyton in turn exerted a strong control on phytoplankton, leading to an indirect negative effect of ARO on phytoplankton. Macrophytes showed little response to the stressors. Multiple pulse exposure increased the effect of ARO on L. stagnalis and periphyton when compared with the same quantity of ARO added as a single dose. The increase in temperature had only limited effects. Our results highlight the importance of indirect effects of stressors, here mediated by grazers and periphyton, and the frequency of the ARO input in aquatic ecosystems.

Published
2021
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22. Rewiring of peatland plant-microbe networks outpaces species turnover

Author

Vincent E. J. Jassey, Bo H. Svensson, Bjorn J. M. Robroek, Marc G. Dumont, Annelies J. Veraart, Magalí Martí, Laboratoire Ecologie Fonctionnelle et Environnement (ECOLAB), Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Université Fédérale Toulouse Midi-Pyrénées-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées, Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Ecologie Fonctionnelle et Environnement (LEFE), Université de Toulouse (UT)-Université de Toulouse (UT)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT), and ANR-17-CE01-0007,MIXOPEAT,Repenser le cycle du carbone des tourbières : identifier le rôle des protistes mixotrophes dans la pompe à carbone biologique(2017)

Subjects
0106 biological sciences, 16S amplicon sequencing, Ekologi, 0303 health sciences, Peat, plant–microbe interactions, Ecology, microbial and plant diversity, plant-microbe interactions, Plant microbe, Aquatic Ecology, 15. Life on land, bipartite networks, 010603 evolutionary biology, 01 natural sciences, 03 medical and health sciences, Environmental science, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, 16S rRNA, Ecology, Evolution, Behavior and Systematics, ComputingMilieux_MISCELLANEOUS, peatlands, 030304 developmental biology
Abstract

International audience; Enviro-climatic changes are thought to be causing alterations in ecosystem processes through shifts in plant and microbial communities; however, how links between plant and microbial communities change with enviro-climatic change is likely to be less straightforward but may be fundamental for many ecological processes. To address this, we assessed the composition of the plant community and the prokaryotic community-using amplicon-based sequencing-of three European peatlands that were distinct in enviro-climatic conditions. Bipartite networks were used to construct sitespecific plant-prokaryote co-occurrence networks. Our data show that between sites, plant and prokaryotic communities differ and that turnover in interactions between the communities was complex. Essentially, turnover in plant-microbial interactions is much faster than turnover in the respective communities. Our findings suggest that network rewiring does largely result from novel or different interactions between species common to all realised networks. Hence, turnover in network composition is largely driven by the establishment of new interactions between a core community of plants and microorganisms that are shared among all sites. Taken together our results indicate that plant-microbe associations are context dependent, and that changes in enviro-climatic conditions will likely lead to network rewiring. Integrating turnover in plant-microbe interactions into studies that assess the impact of enviro-climatic change on peatland ecosystems is essential to understand ecosystem dynamics and must be combined with studies on the impact of these changes on ecosystem processes.

Published
2021
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23. Constraints on potential enzyme activities in thermokarst bogs : Implications for the carbon balance of peatlands following thaw

Author

Liam Heffernan, David Olefeldt, M. Derek MacKenzie, Maya Frederickson, Vincent E. J. Jassey, Laboratoire Ecologie Fonctionnelle et Environnement (ECOLAB), Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées, Laboratoire Ecologie Fonctionnelle et Environnement (LEFE), Université de Toulouse (UT)-Université de Toulouse (UT)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), and Université de Toulouse (UT)

Subjects
Peat, 010504 meteorology & atmospheric sciences, thermokarst, Permafrost, chemistry.chemical_element, 01 natural sciences, Sphagnum, Thermokarst, peat pore water, Greenhouse Gases, Soil, organic matter quality, soil enzyme activities, Environmental Chemistry, Bog, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, General Environmental Science, Ekologi, Global and Planetary Change, geography, geography.geographical_feature_category, biology, Ecology, 04 agricultural and veterinary sciences, Soil carbon, 15. Life on land, biology.organism_classification, Decomposition, Carbon, soil organic carbon, chemistry, 13. Climate action, Wetlands, Environmental chemistry, [SDE]Environmental Sciences, 040103 agronomy & agriculture, 0401 agriculture, forestry, and fisheries, Environmental science, peatland, permafrost
Abstract

Northern peatlands store a globally significant amount of soil organic carbon, much of it found in rapidly thawing permafrost. Permafrost thaw in peatlands often leads to the development and expansion of thermokarst bogs, where microbial activity will determine the stability of the carbon storage and the release of greenhouse gases. In this study, we compared potential enzyme activities between young (thawed ~30 years ago) and mature (~200 years) thermokarst bogs, for both shallow and deep peat layers. We found very low potential enzyme activities in deep peat layers, with no differences between the young and mature bogs. Peat quality at depth was found to be highly humified (FTIR analysis) in both the young and mature bogs. This suggests that deep, old peat was largely stable following permafrost thaw, without a rapid pulse of decomposition during the young bog stage. For near-surface peat, we found significantly higher potential enzyme activities in the young bog than in the mature-associated with differences in peat quality derived from different Sphagnum species. A laboratory incubation of near-surface peat showed that differences in potential enzyme activity were primarily influenced by peat type rather than oxygen availability. This suggested that the young bog can have higher rates of near-surface decomposition despite being substantially wetter than the mature bog. Overall, our study shows that peat properties are the dominant constraint on potential enzyme activity and that peatland site development (successional pathways and permafrost history) through its influence on peat type and chemistry is likely to determine peat decomposition following permafrost thaw.

Published
2021
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24. Functional diversity and trait composition of vascular plant and Sphagnum moss communities during peatland succession across land uplift regions

Author

Eeva-Stiina Tuittila, Anna M. Laine, Oleg Kutznetsov, Mats Nilsson, Vincent E. J. Jassey, Tapio Lindholm, Laboratoire Ecologie Fonctionnelle et Environnement (ECOLAB), Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées, Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Ecologie Fonctionnelle et Environnement (LEFE), Université de Toulouse (UT)-Université de Toulouse (UT)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), and Université de Toulouse (UT)

Subjects
0106 biological sciences, hiilidioksidi, Peat, Plant Science, Ecological succession, muutos, 01 natural sciences, Sphagnum, Russia, sammalet, Mire, conservative species, plant economic spectrum, suot, functional traits, Bog, intraspecific variability, ComputingMilieux_MISCELLANEOUS, Finland, geography.geographical_feature_category, biology, Ecology, pH, phylogenetic signal, vascular plant, food and beverages, functional diversity, succession, communities, climate change, environmental perturbations, ecosystems, Vascular plant, Autogenic succession, coastal areas, 010603 evolutionary biology, moss, resistance, kasvit, rannikot, peat thickness, Ecology, Evolution, Behavior and Systematics, peatlands, Sweden, geography, acquisitive species, trait composition, carbon, fungi, Plant community, coastal regions, 15. Life on land, ilmastonmuutokset, biology.organism_classification, luonnon monimuotoisuus, peatland development, biodiversiteetti, ekosysteemit (ekologia), land uplift regions, resistance to climate change, coasts, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, 010606 plant biology & botany
Abstract

1. Most of the carbon accumulated into peatlands is derived from Sphagnum mosses. During peatland development, the relative share of vascular plants and Sphagnum mosses in the plant community changes, which impacts ecosystem functions. Little is known on the successional development of functional plant traits or functional diversity in peatlands, although this could be a key for understanding the mechanisms behind peatland resistance to climate change. Here we aim to assess how functionality of successive plant communities change along the autogenic peatland development and the associated environmental gradients, namely peat thickness and pH, and to determine whether trait trade-offs during peatland succession are analogous between vascular plant and moss communities. 2. We collected plant community and trait data on successional peatland gradients from post-glacial rebound areas in coastal Finland, Sweden and Russia, altogether from 47 peatlands. This allowed us to analyse the changes in community-weighted mean trait values and functional diversity (diversity of traits) during peatland development. 3. Our results show comparative trait trade-offs from acquisitive species to conservative species in both vascular plant and Sphagnum moss communities during peatland development. However, mosses had higher resistance to environmental change than vascular plant communities. This was seen in the larger proportion of intraspecific trait variation than species turnover in moss traits, while the proportions were opposite for vascular plants. Similarly, the functional diversity of Sphagnum communities increased during the peatland development, while the opposite occurred for vascular plants. Most of the measured traits showed a phylogenetic signal. More so, the species common to old successional stages, namely Ericacae and Sphagna from subgroup Acutifolia were detected as most similar to their phylogenetic neighbours. 4. Synthesis. During peatland development, vegetation succession leads to the dominance of conservative plant species accustomed to high stress. At the same time, the autogenic succession and ecological engineering of Sphagna leads to higher functional diversity and intraspecific variability, which together indicate higher resistance towards environmental perturbations.

Published
2021
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25. Contribution of microbial photosynthesis to peatland carbon uptake along a latitudinal gradient

Author

Joséphine Leflaive, Régis Céréghino, Samuel Hamard, Eeva-Stiina Tuittila, Maialen Barret, Gaël Le Roux, Paul Kardol, Ellen Dorrepaal, Anna Sytiuk, Enrique Lara, Vincent E. J. Jassey, Mariusz Lamentowicz, Martin Küttim, Laboratoire Ecologie Fonctionnelle et Environnement (ECOLAB), Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées, Real Jardín Botánico de Madrid, Spanish National Research Council (CSIC), Umeå University, Swedish University of Agricultural Sciences (SLU), Tallinn University, Adam Mickiewicz University in Poznań (UAM), University of Eastern Finland, Laboratoire Ecologie Fonctionnelle et Environnement (LEFE), Université de Toulouse (UT)-Université de Toulouse (UT)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT), Real Jardín Botánico de Madrid (RJB), and ANR-17-CE01-0007,MIXOPEAT,Repenser le cycle du carbone des tourbières : identifier le rôle des protistes mixotrophes dans la pompe à carbone biologique(2017)

Subjects
0106 biological sciences, Microbial diversity, Peat, Algae, Peatland, Plant Science, Photosynthesis, 010603 evolutionary biology, 01 natural sciences, Carbon cycle, 03 medical and health sciences, [SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, Ecology, Evolution, Behavior and Systematics, 030304 developmental biology, 2. Zero hunger, 0303 health sciences, Carbon dioxide in Earth's atmosphere, Ecology, biology, Phototroph, Community structure, Phototrophs, 15. Life on land, biology.organism_classification, [SDV.MP]Life Sciences [q-bio]/Microbiology and Parasitology, 13. Climate action, Metabarcoding, Primary productivity, Environmental science, Terrestrial ecosystem
Abstract

International audience; Phototrophic microbes, also known as micro-algae, display a high abundance in many terrestrial surface soils. They contribute to atmospheric carbon dioxide fluxes through their photosynthesis, and thus regulate climate similar to plants. However, microbial photosynthesis remains overlooked in most terrestrial ecosystems. Here, we hypothesize that phototrophic microbes significantly contribute to peatland C uptake, unless environmental conditions limit their development and their photosynthetic activity.To test our hypothesis, we studied phototrophic microbial communities in five peatlands distributed along a latitudinal gradient in Europe. By means of metabarcoding, microscopy and cytometry analyses, as well as measures of photosynthesis, we investigated the diversity, absolute abundance and photosynthetic rates of the phototrophic microbial communities.We identified 351 photosynthetic prokaryotic and eukaryotic operational taxonomic units (OTU) across the five peatlands. We found that water availability and plant composition were important determinants of the composition and the structure of phototrophic microbial communities. Despite environmental shifts in community structure and composition, we showed that microbial C-fixation rates remained similar along the latitudinal gradient. Our results further revealed that phototrophic microbes accounted for approximately 10% of peatland C uptake.Synthesis. Our findings show that phototrophic microbes are extremely diverse and abundant in peatlands. While species turnover with environmental conditions, microbial photosynthesis similarly contributed to peatland C uptake at all latitudes. We estimate that phototrophic microbes take up around 75 MT CO2 per year in northern peatlands. This amount roughly equals the magnitude of projected peatland C loss due to climate warming and highlight the importance of phototrophic microbes for the peatland C cycle

Published
2021
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26. Predicting the structure and functions of peatland microbial communities from Sphagnum phylogeny, anatomical and morphological traits and metabolites

Author

Bertrand Pourrut, Régis Céréghino, Ellen Dorrepaal, Mariusz Lamentowicz, Amélie Guittet, Anna Sytiuk, Samuel Hamard, Eeva-Stiina Tuittila, Martin Küttim, Janna M. Barel, Vincent E. J. Jassey, Frédéric Delarue, Bjorn J. M. Robroek, Laboratoire Ecologie Fonctionnelle et Environnement (LEFE), Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT), Milieux Environnementaux, Transferts et Interactions dans les hydrosystèmes et les Sols (METIS), École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), ANR-17-CE01-0007,MIXOPEAT,Repenser le cycle du carbone des tourbières : identifier le rôle des protistes mixotrophes dans la pompe à carbone biologique(2017), Laboratoire Ecologie Fonctionnelle et Environnement (ECOLAB), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), École pratique des hautes études (EPHE), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)

Subjects
0106 biological sciences, 0303 health sciences, Peat, Ecology, biology, Aquatic Ecology, Plant Science, 15. Life on land, biology.organism_classification, 010603 evolutionary biology, 01 natural sciences, Sphagnum, 03 medical and health sciences, Metabolomics, Phylogenetics, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Ecology, Evolution, Behavior and Systematics, ComputingMilieux_MISCELLANEOUS, 030304 developmental biology
Abstract

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Published
2021
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27. Assessing the responses of Sphagnum micro-eukaryotes to climate changes using high throughput sequencing

Author

Matthieu Mulot, Vincent E. J. Jassey, Christophe V. W. Seppey, Sandra Słowińska, Mariusz Lamentowicz, Monika Reczuga, Enrique Lara, Michał Słowiński, Alexandre Buttler, Edward A. D. Mitchell, Laboratoire Ecologie Fonctionnelle et Environnement (ECOLAB), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Ecologie Fonctionnelle et Environnement (LEFE), Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), and Université de Toulouse (UT)

Subjects
0106 biological sciences, VDP::Mathematics and natural science: 400::Zoology and botany: 480::Ecology: 488, Peat, warming, Biodiversity, lcsh:Medicine, Climate change, Biology, 010603 evolutionary biology, 01 natural sciences, General Biochemistry, Genetics and Molecular Biology, wetlands, diversity, Carbon cycle, food-web, VDP::Matematikk og Naturvitenskap: 400::Zoologiske og botaniske fag: 480::Økologi: 488, 03 medical and health sciences, carbon-cycle, patterns, Ecosystem, ComputingMilieux_MISCELLANEOUS, biodiversity, 030304 developmental biology, protists, 2. Zero hunger, 0303 health sciences, Ecology, General Neuroscience, lcsh:R, Global warming, temperature, General Medicine, Soil carbon, 15. Life on land, populations, 13. Climate action, short-term, impact, water table manipulation, peatland, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, community structure, Ecosystem respiration, General Agricultural and Biological Sciences, testate amebas
Abstract

Current projections suggest that climate warming will be accompanied by more frequent and severe drought events. Peatlands store ca. one third of the world’s soil organic carbon. Warming and drought may cause peatlands to become carbon sources through stimulation of microbial activity increasing ecosystem respiration, with positive feedback effect on global warming. Micro-eukaryotes play a key role in the carbon cycle through food web interactions and therefore, alterations in their community structure and diversity may affect ecosystem functioning and could reflect these changes. We assessed the diversity and community composition of Sphagnum-associated eukaryotic microorganisms inhabiting peatlands and their response to experimental drought and warming using high throughput sequencing of environmental DNA. Under drier conditions, micro-eukaryotic diversity decreased, the relative abundance of autotrophs increased and that of osmotrophs (including Fungi and Peronosporomycetes) decreased. Furthermore, we identified climate change indicators that could be used as early indicators of change in peatland microbial communities and ecosystem functioning. The changes we observed indicate a shift towards a more “terrestrial” community in response to drought, in line with observed changes in the functioning of the ecosystem.

Published
2020
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28. Author response for 'Functional diversity and trait composition of vascular plant and Sphagnum moss communities during peatland succession across land uplift regions'

Author

Tapio Lindholm, Mats Nilsson, Oleg Kutznetsov, Eeva-Stiina Tuittila, Vincent E. J. Jassey, and Anna Laine

Subjects
Vascular plant, Geography, Peat, biology, Ecology, Trait, Land uplift, Composition (visual arts), Ecological succession, biology.organism_classification, Sphagnum, Moss
Published
2020
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29. Unveiling tipping points in long-term and experimental studies in peatlands

Author

Katarzyna Marcisz, Vincent E. J. Jassey, Michał Słowiński, and Mariusz Lamentowicz

Subjects
Peat, Environmental science, Physical geography, Term (time)
Abstract

Ecosystems are increasingly prone to climate extremes, such as drought, with long-lasting effects on both plant and soil communities and, subsequently, on carbon (C) cycling. Unveiling past tipping points is a prerequisite for a better understanding of how individual species and entire ecosystems will respond to future climate changes, especially soil moisture. In the first study we identified the response of peatland vegetation to shifts in hydrological conditions over the past 2000 years using plant macrofossils, testate amoebae-based quantitative hydrological reconstructions from seven Polish peat-records (Lamentowicz et al., 2019). Using threshold indicator taxa analysis (TITAN), we discovered that plant community composition strongly converged at a water level of c. 11.7 cm, indicating a community-level tipping-point. We identified 45 plant taxa that showed either an increase or a decrease in their relative abundance between 8 and 17 cm of water level depth. In other the experimental study (Jassey et al., 2018) we investigated the response of plant and soil fungi to drought of different intensities using a water table gradient in peatlands—a major C sink ecosystem. We show that substantial changes in ecosystem respiration, plant and soil fungal communities occurred when the water level fell below a tipping point of 24 cm. As a corollary, ecosystem respiration was the greatest when graminoids and saprotrophic fungi became prevalent as a response to the extreme drought. Graminoids indirectly influenced fungal functional composition and soil enzyme activities through their direct effect on dissolved organic matter quality, while saprotrophic fungi directly influenced soil enzyme activities. In turn, increasing enzyme activities promoted ecosystem respiration. We show that functional transitions in ecosystem respiration critically depend on the degree of response of graminoids and saprotrophic fungi to drought. Our results represent a major advance in understanding the nonlinear nature of ecosystem properties to drought and pave the way towards a truly mechanistic understanding of tipping points in peatlands with use of experiment and palaeoecology.ReferencesJassey, V.E.J., Reczuga, M.K., Zielinska, M., Slowinska, S., Robroek, B.J.M., Mariotte, P., Seppey, C.V.W., Lara, E., Barabach, J., Slowinski, M., Bragazza, L., Chojnicki, B.H., Lamentowicz, M., Mitchell, E.A.D., Buttler, A., 2018. Tipping point in plant-fungal interactions under severe drought causes abrupt rise in peatland ecosystem respiration. Glob Chang Biol. 24, (3) 972–986.Lamentowicz, M., Gałka, M., Marcisz, K., Słowiński, M., Kajukało-Drygalska, K., Dayras, M.D., Jassey, V.E.J., 2019. Unveiling tipping points in long-term ecological records from Sphagnum -dominated peatlands. Biology Letters. 15, (4) 20190043.

Published
2020
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30. From Climatic to Anthropogenic Drivers: A Multi-Proxy Reconstruction of Vegetation and Peatland Development in the French Jura Mountains

Author

Daniel Gilbert, Frédéric Delarue, Emilie Gauthier, Richard J. Payne, Vincent E. J. Jassey, Edward A. D. Mitchell, Mariusz Lamentowicz, Hervé Richard, Fatima Laggoun-Défarge, Laboratoire Chrono-environnement - CNRS - UBFC (UMR 6249) (LCE), Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Laboratoire Ecologie Fonctionnelle et Environnement (ECOLAB), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Université de Neuchâtel (UNINE), Laboratory ofWetland Ecology and Monitoring, and Department of Biogeography and Paleoecology, Adam Mickiewicz University in Poznań (UAM), Environment and Geography, University of York, Institut de minéralogie, de physique des matériaux et de cosmochimie (IMPMC), Muséum national d'Histoire naturelle (MNHN)-Institut de recherche pour le développement [IRD] : UR206-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences de la Terre d'Orléans - UMR7327 (ISTO), Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM), Biogéosystèmes Continentaux - UMR7327, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers en région Centre (OSUC), ANR-07-VULN-0010,PEATWARM,Impact du réchauffement climatique sur la focntion de puits de carbone de l'ecosysteme tourbières à sphaignes.(2007), Laboratoire Chrono-environnement (UMR 6249) (LCE), Laboratoire Ecologie Fonctionnelle et Environnement (LEFE), Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC)

Subjects
010506 paleontology, Peat, human impact, 010504 meteorology & atmospheric sciences, 01 natural sciences, law.invention, Jura Mountains, law, Evapotranspiration, Mire, Earth and Planetary Sciences (miscellaneous), Radiocarbon dating, Testate amoebae, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, palynology, climate, Holocene, 0105 earth and related environmental sciences, Earth-Surface Processes, Palynology, Vegetation, 15. Life on land, testate amoebae, [SDU]Sciences of the Universe [physics], Environmental science, Physical geography
Abstract

International audience; A 4 m core was extracted from the center of a peatland located in the Drugeon valley (France). Thirteen radiocarbon dates were used to build a robust age model. Testate amoebae were used for reconstructing mire surface wetness. High-resolution pollen analysis of the sequence reconstructed 9 millennia of development of the peatland and its surrounding vegetation. During the early/middle Holocene (9500 to 5800 cal BP), warm conditions led to high evapotranspiration and low water levels. The vegetation history is characterized by the development of a Pinus and a mixed Quercus forest. From 5800 cal BP, testate amoebae show wetter conditions, indicating the onset of the cooler Neoglacial period. The cooling is also evidenced by the development of Abies and Fagus trees, replacing the oak forest. The first indicators of human impact appear at about 4800 cal BP, and indicators of farming activity remains very rare until ca. 2600 cal BP, at the beginning of the Iron Age. The development of the peatland responded to climatic fluctuation until 2600 cal BP, after which human impact became the main driver. The last millennium has been characterized by sudden drying and the spread of pine on the peatland.

Published
2019
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31. Assessing the responses of

Author

Monika K, Reczuga, Christophe Victor William, Seppey, Matthieu, Mulot, Vincent E J, Jassey, Alexandre, Buttler, Sandra, Słowińska, Michał, Słowiński, Enrique, Lara, Mariusz, Lamentowicz, and Edward A D, Mitchell

Subjects
Ecology, Wetlands, Water table manipulation, Food-web, Climate Change Biology, Soil Science, Biodiversity, Protists, Warming, Community structure
Abstract

Current projections suggest that climate warming will be accompanied by more frequent and severe drought events. Peatlands store ca. one third of the world’s soil organic carbon. Warming and drought may cause peatlands to become carbon sources through stimulation of microbial activity increasing ecosystem respiration, with positive feedback effect on global warming. Micro-eukaryotes play a key role in the carbon cycle through food web interactions and therefore, alterations in their community structure and diversity may affect ecosystem functioning and could reflect these changes. We assessed the diversity and community composition of Sphagnum-associated eukaryotic microorganisms inhabiting peatlands and their response to experimental drought and warming using high throughput sequencing of environmental DNA. Under drier conditions, micro-eukaryotic diversity decreased, the relative abundance of autotrophs increased and that of osmotrophs (including Fungi and Peronosporomycetes) decreased. Furthermore, we identified climate change indicators that could be used as early indicators of change in peatland microbial communities and ecosystem functioning. The changes we observed indicate a shift towards a more “terrestrial” community in response to drought, in line with observed changes in the functioning of the ecosystem.

Published
2019

32. Soil microbial community structure and enzymatic activity along a plant cover gradient in Victoria Land (continental Antarctica)

Author

Mauro Guglielmin, Bjorn J. M. Robroek, Vincent E. J. Jassey, Luca Bragazza, Roberta Marchesini, Muhammad Arif, Nicoletta Cannone, Laboratory of Soil Biology, Université de Neuchâtel (UNINE), Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Laboratoire Ecologie Fonctionnelle et Environnement (ECOLAB), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), and Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Total organic carbon, Biomass (ecology), [SDE.MCG]Environmental Sciences/Global Changes, Soil Science, Biogeochemistry, 04 agricultural and veterinary sciences, Soil carbon, 010501 environmental sciences, 15. Life on land, complex mixtures, 01 natural sciences, Microbial population biology, Environmental chemistry, Soil water, 040103 agronomy & agriculture, 0401 agriculture, forestry, and fisheries, Environmental science, Plant cover, Lichen, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract

In continental Antarctica, autotrophs are exclusively represented by cyanobacteria, algae, lichens and mosses. Consequently, Antarctic soil communities are expected to be rather simple and primarily dominated by microorganisms. Recently, a change in abundance of mosses and lichens has been observed in continental Antarctica in response to an increase of the active permafrost layer, but the implication of this change to soil micro-organisms remains little known. Here we aim to clarify to what extent the abundance of mosses and lichens affects soil biogeochemistry in Victoria Land, with a particular focus on soil microbial abundance and associated soil enzymatic activity. To achieve this aim, we assessed the structure of soil microbiome and the activity of hydrolytic C, N, and P enzymes along a gradient in soil physico-chemical conditions and plant cover. Moss cover strongly relates to the amount of soil organic carbon (SOC), soil water and nutrient content. Soils with higher content of organic carbon were characterized by higher microbial biomass and showed a relatively higher abundance of fungi as compared to bacteria. More specifically, PLFAs biomarkers for Actinomycetes and Gram-positive bacteria were mainly associated to soils with lower SOC. In order to sustain a higher microbial biomass, total activity of hydrolytic enzymes increased with increasing SOC content. Eco-enzymatic stoichiometry, based on C to P and C to N ratios, indicates a higher investment in N- and P-hydrolytic enzymes (ratio < 1), particularly at low SOC content. Oppositely, an increase in C-hydrolytic enzyme activity (ratio ≈ 1) was observed with increasing accumulation of organic carbon. Such a result seems to indicate a stronger role of soil pH at low SOC on enzymatic stoichiometry (abiotic control) whereas with increasing accumulation of organic matter the enzymatic stoichiometry is more affected by microbial metabolism (biotic control).

Published
2019
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33. Effects of climate warming on Sphagnum photosynthesis in peatlands depend on peat moisture and species‐specific anatomical traits

Author

Constant Signarbieux, Vincent E. J. Jassey, Laboratoire Chrono-environnement - CNRS - UBFC (UMR 6249) (LCE), Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), and Laboratory of Geographic Information Systems (LASIG), School of Architecture, Civil and Environmental Engineering (ENAC), École Polytechnique Fédérale de Lausanne (EPFL)

Subjects
0106 biological sciences, Peat, 010504 meteorology & atmospheric sciences, Climate Change, Rain, [SDE.MCG]Environmental Sciences/Global Changes, Climate change, 010603 evolutionary biology, 01 natural sciences, Sphagnum, Soil, Sphagnopsida, Environmental Chemistry, Ecosystem, Photosynthesis, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, General Environmental Science, Global and Planetary Change, Ecology, biology, Global warming, 15. Life on land, biology.organism_classification, Sphagnum magellanicum, Photosynthetic capacity, Sphagnum fallax, 13. Climate action, Environmental science
Abstract

Climate change will influence plant photosynthesis by altering patterns of temperature and precipitation, including their variability and seasonality. Both effects may be important for peatlands as the carbon (C) sink potential of these ecosystems depends on the balance between plant C uptake through photosynthesis and microbial decomposition. Here, we show that the effect of climate warming on Sphagnum community photosynthesis toggles from positive to negative as the peatland goes from rainy to dry periods during summer. More particularly, we show that mechanisms of compensation among the dominant Sphagnum species (Sphagnum fallax and Sphagnum medium) stabilize the average photosynthesis and productivity of the Sphagnum community during summer despite rising temperatures and frequent droughts. While warming had a negligible effect on S. medium photosynthetic capacity (Amax ) during rainy periods, Amax of S. fallax increased by 40%. On the opposite, warming exacerbated the negative effects of droughts on S. fallax with an even sharper decrease of its Amax while S. medium Amax remained unchanged. S. medium showed a remarkable resistance to droughts due to anatomical traits favouring its water holding capacity. Our results show that different phenotypic plasticity among dominant Sphagnum species allow the community to cope with rising temperatures and repeated droughts, maintaining similar photosynthesis and productivity over summer in warmed and control conditions. These results are important because they provide information on how soil water content may modulate the effects of climate warming on Sphagnum productivity in boreal peatlands. It further confirms the transitory nature of warming-induced photosynthesis benefits in boreal systems and highlights the vulnerability of the ecosystem to excess warming and drying.

Published
2019
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34. Correction: Long-term in situ permafrost thaw effects on bacterial communities and potential aerobic respiration

Author

Sylvain Monteux, James T. Weedon, Gesche Blume-Werry, Konstantin Gavazov, Vincent E. J. Jassey, Margareta Johansson, Frida Keuper, Carolina Olid, Ellen Dorrepaal, Systems Ecology, Climate Impacts Research Centre (CIRC), Umeå University, Department of Ecological Sciences, Vrije Universiteit Amsterdam [Amsterdam] (VU)-Vrije Universiteit Amsterdam [Amsterdam] (VU), Plant and Vegetation Ecology (PLECO), University of Antwerp (UA), Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Laboratoire Ecologie Fonctionnelle et Environnement (ECOLAB), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Department of Physical Geography and Ecosystem Science [Lund], Lund University [Lund], Agroressources et Impacts environnementaux (AgroImpact), and Institut National de la Recherche Agronomique (INRA)

Subjects
[SDV.EE]Life Sciences [q-bio]/Ecology, environment, 0303 health sciences, 03 medical and health sciences, SDG 16 - Peace, [SDV.MP]Life Sciences [q-bio]/Microbiology and Parasitology, 030306 microbiology, SDG 16 - Peace, Justice and Strong Institutions, Microbiology, Justice and Strong Institutions, Ecology, Evolution, Behavior and Systematics, ComputingMilieux_MISCELLANEOUS, 030304 developmental biology
Abstract

Since the publication of the original article, the authors noticed some errors in reference citation had been introduced throughout the paper. The following text contains excerpts from the original article and how they should appear with correct referencing. The publisher apologises for any inconvenience this has caused readers.

Published
2019
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35. Unveiling tipping points in long-term ecological records from Sphagnum-dominated peatlands

Author

Michał Słowiński, Vincent E. J. Jassey, Katarzyna Kajukało-Drygalska, Mariusz Lamentowicz, Milva Druguet Dayras, Katarzyna Marcisz, Mariusz Gałka, Adam Mickiewicz University in Poznań (UAM), Laboratory of Wetland Ecology and Monitoring, Faculty of Geographical and Geological Sciences, Department of Geoecology and Climatology, Institute of Geography and Spatial Organization, Polska Akademia Nauk = Polish Academy of Sciences (PAN), Laboratoire Ecologie Fonctionnelle et Environnement (ECOLAB), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), and Polish Academy of Sciences

Subjects
0106 biological sciences, Peat, 010504 meteorology & atmospheric sciences, media_common.quotation_subject, 010603 evolutionary biology, 01 natural sciences, Sphagnum, Corrections, Sphagnopsida, Ecosystem, Amoeba, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, media_common, biology, Ecology, Biodiversity, 15. Life on land, Future climate, biology.organism_classification, Agricultural and Biological Sciences (miscellaneous), Term (time), Critical transition, Psychological resilience, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, General Agricultural and Biological Sciences
Abstract

Unveiling past tipping points is a prerequisite for a better understanding of how individual species and entire ecosystems will respond to future climate change. Such knowledge is key for the implementation of biodiversity conservation. We identify the relationships between peatland vegetation and hydrological conditions over the past 2000 years using plant macrofossils, testate amoebae-based quantitative hydrological reconstructions and Sphagnum -moss functional traits from seven Polish peatland records. Using threshold indicator taxa analysis, we discovered that plant community composition strongly converged at a water level of ca 11.7 cm, indicating a community-level tipping point. We identified 45 plant taxa that showed either an increase or a decrease in their relative abundance between 8 and 17 cm of water-level depth. Our analysis of Sphagnum community traits further showed that Sphagnum functional diversity was remarkably stable over time despite Sphagnum species sensitivity to hydrological conditions. Our results suggest that past hydrological shifts did not influence major functions of the Sphagnum community, such as photosynthetic capacity, growth and productivity, owing to species replacement with a similar functional space. Although further studies including trait plasticity will be required, our findings suggest that the capacity of the Sphagnum community to gain carbon remained stable despite hydrological changes.

Published
2019
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36. Unveiling exceptional Baltic bog ecohydrology, autogenic succession and climate change during the last 2000 years in CE Europe using replicate cores, multi-proxy data and functional traits of testate amoebae

Author

Willem Oscar van der Knaap, Mariusz Gałka, Vasile Ersek, Łukasz Lamentowicz, Kazimierz Tobolski, Vincent E. J. Jassey, Mariusz Lamentowicz, Adam Mickiewicz University in Poznań (UAM), University of Northumbria at Newcastle [United Kingdom], Laboratoire Ecologie Fonctionnelle et Environnement (ECOLAB), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Laboratory of Wetland Ecology and Monitoring, and Faculty of Geographical and Geological Sciences, Adam Mickiewicz University

Subjects
Autogenic succession, 010506 paleontology, Archeology, Peat, Peatland, 010504 meteorology & atmospheric sciences, F400, Climate change, F800, 01 natural sciences, Sphagnum, Ecohydrology, Mire, Testate amoebae, Bog, ComputingMilieux_MISCELLANEOUS, Ecology, Evolution, Behavior and Systematics, 0105 earth and related environmental sciences, Global and Planetary Change, geography, geography.geographical_feature_category, Holocene, biology, Ecology, Geology, Sphagnum succession, 15. Life on land, biology.organism_classification, 13. Climate action, [SDE]Environmental Sciences, Pollen, Environmental science, Palaeohydrology, Plant macrofossils
Abstract

We present the results of high-resolution, multi-proxy palaeoecological investigations of two parallel peat cores from the Baltic raised bog Mechacz Wielki in NE Poland. We aim to evaluate the role of regional climate and autogenic processes of the raised bog itself in driving the vegetation and hydrology dynamics. Based on partly synchronous changes in Sphagnum communities in the two study cores we suggest that extrinsic factors (climate) played an important role as a driver in mire development during the bog stage (500-2012 CE). Using a testate amoebae transfer function, we found exceptionally stable hydrological conditions during the last 2000 years with a relatively high water table and lack of local fire events that allowed for rapid peat accumulation (2.75 mm/year) in the bog. Further, the strong correlation between pH and community-weighted mean of testate amoeba traits suggests that other variables than water-table depth play a role in driving microbial properties under stable hydrological conditions. There is a difference in hydrological dynamics in bogs between NW and NE Poland until ca 1500 CE, after which the water table reconstructions show more similarities. Our results illustrate how various functional traits relate to different environmental variables in a range of trophic and hydrological scenarios on long time scales. Moreover, our data suggest a common regional climatic forcing in Mechacz Wielki, Gazwa and Kontolanrahka. Though it may still be too early to attempt a regional summary of wetness change in the southern Baltic region, this study is a next step to better understand the long-term peatland palaeohydrology in NE Europe. (C) 2016 Elsevier Ltd. All rights reserved.

Published
2017
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37. Testate amoebae taxonomy and trait diversity are coupled along an openness and wetness gradient in pine-dominated Baltic bogs

Author

Monika Karpińska-Kołaczek, Vincent E. J. Jassey, Piotr Kołaczek, Mariusz Lamentowicz, Katarzyna Kajukało-Drygalska, Maciej Gąbka, Laboratoire Ecologie Fonctionnelle et Environnement (ECOLAB), Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), and Université Fédérale Toulouse Midi-Pyrénées

Subjects
Baltic States, 0301 basic medicine, Peat, Heterotroph, Forests, Microbiology, Sphagnum, 03 medical and health sciences, Amoeba, Testate amoebae, Bog, Relative species abundance, ComputingMilieux_MISCELLANEOUS, Ecosystem, Demography, geography, geography.geographical_feature_category, biology, Ecology, Carbon sink, Biodiversity, 15. Life on land, 030108 mycology & parasitology, biology.organism_classification, Light intensity, 030104 developmental biology, Sunlight, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Hydrology
Abstract

Sphagnum peatlands host a high abundance of protists, especially testate amoebae. Here, we designed a study to investigate the functional diversity of testate amoebae in relation to wetness and forest cover in Baltic bogs. We provided new data on the influence of openness/wetness gradient on testate amoebae communities, showing significant differences in selected testate amoebae (TA) traits. Three key messages emerged from our investigations: 1) we recorded an effect of peatland surface openness on testate amoebae functional traits that led us to accept the hypothesis that TA traits differ according to light intensity and hydrology. Mixotrophic species were recorded in high relative abundance in open plots, whereas they were nearly absent in forested sites; 2) we revealed a hydrological threshold for the occurrence of mixotrophic testate amoebae that might be very important in terms of peatland functioning and carbon sink vs. source context; and 3) mixotrophic species with organic tests were nearly absent in forested sites that were dominated by heterotrophic species with agglutinated or idiosomic tests. An important message from this study is that taxonomy of TA rather indicates the hydrological gradient whereas traits of mixotrophs the openness gradient.

Published
2020
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38. Long-term in situ permafrost thaw effects on bacterial communities and potential aerobic respiration

Author

Konstantin Gavazov, James T. Weedon, Carolina Olid, Ellen Dorrepaal, Gesche Blume-Werry, Sylvain Monteux, Frida Keuper, Margareta Johansson, Vincent E. J. Jassey, Systems Ecology, Department of Ecological Science [Amsterdam], Vrije Universiteit Brussel (VUB), Ecole Polytechnique Fédérale de Lausanne (EPFL), Laboratoire Ecologie Fonctionnelle et Environnement (ECOLAB), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Department of Systems Ecology, University of Amsterdam [Amsterdam] (UvA), Climate Impacts Research Centre (CIRC), Umeå University, Laboratoire Ecologie Fonctionnelle et Environnement (LEFE), Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), and Université de Toulouse (UT)

Subjects
0301 basic medicine, Cellular respiration, [SDE.MCG]Environmental Sciences/Global Changes, Permafrost, Biology, Microbiology, Article, 03 medical and health sciences, Respiration, SDG 13 - Climate Action, Organic matter, Ecology, Evolution, Behavior and Systematics, 2. Zero hunger, chemistry.chemical_classification, Ekologi, Bacteria, Ecology, Correction, Soil chemistry, Soil carbon, 15. Life on land, Miljövetenskap, Aerobiosis, Carbon, Active layer, Chemistry, 030104 developmental biology, chemistry, 13. Climate action, Environmental chemistry, Soil water, Environmental Sciences
Abstract

The decomposition of large stocks of soil organic carbon in thawing permafrost might depend on more than climate change-induced temperature increases: indirect effects of thawing via altered bacterial community structure (BCS) or rooting patterns are largely unexplored. We used a 10-year in situ permafrost thaw experiment and aerobic incubations to investigate alterations in BCS and potential respiration at different depths, and the extent to which they are related with each other and with root density. Active layer and permafrost BCS strongly differed, and the BCS in formerly frozen soils (below the natural thawfront) converged under induced deep thaw to strongly resemble the active layer BCS, possibly as a result of colonization by overlying microorganisms. Overall, respiration rates decreased with depth and soils showed lower potential respiration when subjected to deeper thaw, which we attributed to gradual labile carbon pool depletion. Despite deeper rooting under induced deep thaw, root density measurements did not improve soil chemistry-based models of potential respiration. However, BCS explained an additional unique portion of variation in respiration, particularly when accounting for differences in organic matter content. Our results suggest that by measuring bacterial community composition, we can improve both our understanding and the modeling of the permafrost carbon feedback. A correction to this article has been published. DOI: 10.1038/s41396-019-0384-1

Published
2018
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39. Seasonality alters drivers of soil enzyme activity in subalpine grassland soil undergoing climate change

Author

Jean-Jacques Brun, Alexandre Buttler, Bjorn J. M. Robroek, Konstantin Gavazov, Sébastien De Danieli, Robert I. Griffiths, Lauric Cécillon, Robert T. E. Mills, Vincent E. J. Jassey, Thomas Spiegelberger, Jeremy Puissant, Laboratoire Ecologie Fonctionnelle et Environnement (ECOLAB), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Ecole Polytechnique Fédérale de Lausanne (EPFL), Ecosystèmes montagnards (UR EMGR), Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), Laboratoire des systèmes écologiques (ECOS), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry]), Unité Ecosystèmes Montagnards, Centre national du machinisme agricole, du génie rural, des eaux et forêts (CEMAGREF), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées, and Swiss Federal Institute for Forest, Snow and Avalanche Research WSL

Subjects
temperature sensitivity, soil organic matter fractions, dissolved organic-matter, 010504 meteorology & atmospheric sciences, growing-season, Soil Science, Climate change, 01 natural sciences, Microbiology, climate manipulation, structural equation models, current knowledge, land-use, path analysis, Organic matter, Ecosystem, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, 2. Zero hunger, chemistry.chemical_classification, decomposition, Soil organic matter, Global warming, 04 agricultural and veterinary sciences, Soil carbon, Mineralization (soil science), 15. Life on land, SUISSE, carbon pools, chemistry, Agronomy, Agriculture and Soil Science, microbial community structure, 13. Climate action, Soil water, soil microbial communities, 040103 agronomy & agriculture, co2, 0401 agriculture, forestry, and fisheries, Environmental science, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, recalcitrance, feedbacks
Abstract

International audience; In mountain ecosystems with marked seasonality, climate change can affect various processes in soils, potentially modifying long-term key soil services via change in soil organic carbon (C) storage. Based on a four-year soil transplantation experiment in Swiss subalpine grasslands, we investigated how imposed climate warming and reduced precipitation modified the drivers of soil carbon enzyme potential activities across winter and summer seasons. Specifically, we used structural equation models (SEMs) to identify biotic (microbial community structure, abundance and activity) and abiotic (quantity and quality of organic matter resources) drivers of soil C-enzymes (hydrolase and oxidase) in two seasons under two different climate scenarios. We found contrasting impacts of the climate manipulation on the drivers of C-enzymes between winter and summer. In winter, no direct effect of climate manipulation (reduced rainfall and warming) on enzyme activity was observed. Yet, climate indirectly down-regulated enzyme activity through a decrease in the availability of water extractable organic carbon (WEOC) labile resources. During summer, reduced soil moisture -induced by the climate manipulation- directly reduced soil microbial biomass, which led to a decrease in C-enzyme activity. In general, across both seasons, neither microbial community structure, nor organic matter quality were strong determinants of enzymatic activity. In particular organic matter recalcitrance (aromaticity) was not found as a general driver of either hydrolase or oxidase C-enzyme potential activities, though we did observe higher C-enzyme activities led to an increase of particulate organic matter recalcitrance in the summer season. Overall, our results highlight the seasonality of climate change effects on soil organic matter enzymatic decomposition, providing a comprehensive picture of seasonal potential cause and effect relationships governing C mineralization in subalpine grassland.

Published
2018
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40. Effects of

Author

Samuel, Hamard, Bjorn J M, Robroek, Pierre-Marie, Allard, Constant, Signarbieux, Shuaizhen, Zhou, Tongchai, Saesong, Flore, de Baaker, Alexandre, Buttler, Geneviève, Chiapusio, Jean-Luc, Wolfender, Luca, Bragazza, and Vincent E J, Jassey

Subjects
plant competition, plant-exudates, microbial networks, microbial respiration and biomass, peatland, soil food-web, Microbiology, metabolomics, allelopathy and allelochemicals, Original Research
Abstract

Plant specialized metabolites play an important role in soil carbon (C) and nutrient fluxes. Through anti-microbial effects, they can modulate microbial assemblages and associated microbial-driven processes, such as nutrient cycling, so to positively or negatively cascade on plant fitness. As such, plant specialized metabolites can be used as a tool to supplant competitors. These compounds are little studied in bryophytes. This is especially notable in peatlands where Sphagnum mosses can dominate the vegetation and show strong interspecific competition. Sphagnum mosses form carpets where diverse microbial communities live and play a crucial role in Sphagnum fitness by regulating C and nutrient cycling. Here, by means of a microcosm experiment, we assessed to what extent moss metabolites of two Sphagnum species (S. fallax and S. divinum) modulate the competitive Sphagnum microbiome, with particular focus on microbial respiration. Using a reciprocal leachate experiment, we found that interactions between Sphagnum leachates and microbiome are species-specific. We show that both Sphagnum leachates differed in compound richness and compound relative abundance, especially sphagnum acid derivates, and that they include microbial-related metabolites. The addition of S. divinum leachate on the S. fallax microbiome immediately reduced microbial respiration (−95%). Prolonged exposition of S. fallax microbiome to S. divinum leachate destabilized the food web structure due to a modulation of microbial abundance. In particular, leachate addition decreased the biomass of testate amoebae and rotifers but increased that of ciliates. These changes did not influence microbial CO2 respiration, suggesting that the structural plasticity of the food web leads to its functional resistance through the replacement of species that are functionally redundant. In contrast, S. fallax leachate neither affected S. divinum microbial respiration, nor microbial biomass. We, however, found that S. fallax leachate addition stabilized the food web structure associated to S. divinum by changing trophic interactions among species. The differences in allelopathic effects between both Sphagnum leachates might impact their competitiveness and affect species distribution at local scale. Our study further paves the way to better understand the role of moss and microbial specialized metabolites in peatland C dynamics.

Published
2018

41. The Impact of Experimental Temperature and Water Level Manipulation on Carbon Dioxide Release in a Poor Fen in Northern Poland

Author

Kamila M. Harenda, Mariusz Lamentowicz, Bjorn J. M. Robroek, Małgorzata Zielińska, Sandra Słowińska, Bogdan H. Chojnicki, Alexandre Buttler, Mateusz Samson, Michał Słowiński, Vincent E. J. Jassey, Jan Barabach, Department of Geoecology and Climatology, Institute of Geography and Spatial Organization, Polish Academy of Sciences, Institute of Physics [Toruń], Faculty of Physics, Astronomy and Informatics [Toruń], Nicolaus Copernicus University [Toruń]-Nicolaus Copernicus University [Toruń], Laboratory of Wetland Ecology and Monitoring, Faculty of Geographical and Geological Sciences, Adam Mickiewicz University, University of Southampton, Laboratoire Chrono-environnement - CNRS - UBFC (UMR 6249) (LCE), Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Laboratoire des systèmes écologiques (ECOS), Ecole Polytechnique Fédérale de Lausanne (EPFL), Faculty of Environment Engineering and Spatial Management, Department of Meteorology, Poznan University of Life Sciences, and Polska Akademia Nauk = Polish Academy of Sciences (PAN)

Subjects
0106 biological sciences, geography, Peat, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, Ecology, Water table, Global warming, Wetland, Atmospheric sciences, 010603 evolutionary biology, 01 natural sciences, chemistry.chemical_compound, chemistry, 13. Climate action, Carbon dioxide, [SDE]Environmental Sciences, Environmental Chemistry, Environmental science, Poor fen, Ecosystem, Ecosystem respiration, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, General Environmental Science
Abstract

Peatlands are ecosystems for which carbon budget relies strongly on the meteorological and hydrological conditions. Here, using a manipulative field experiment, we measured ecosystem respiration (RECO) over two years (2013–2014) in a poor fen in Poland to estimate the carbon emission in a changing climate. The experiment consisted of warming (open-top chambers - OTC) and water table manipulation. The application of OTC increased the mean values of daily maximum air temperature by approx. 1.1–1.8 °C. Warming or the increased water table depth separately resulted in an increase in ecosystem respiration by approx. 0.1 μmol CO2 m−2 s−1 and 0.3 μmol CO2 m−2 s−1, respectively. However, our results show also the additive nature of warming and water table drawdown impact on daily RECO during the studied years (2013–0.80 μmol CO2 m−2 s−1 and 2014–1.16 μmol CO2 m−2 s−1). With the natural dry period event which occurred in 2014, the seasonal RECO increased by approx. 0.2 μmol CO2 m−2 s−1 as compared to the previous year. Projected global warming will therefore significantly enhance C loss from poor fens in this region of Europe.

Published
2018
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42. Peatland vascular plant functional types affect dissolved organic matter chemistry

Author

Luca Bragazza, Vincent E. J. Jassey, Samuel Hamard, Remy Albrecht, Alexandre Buttler, Adrian Pulgarin, Bjorn J. M. Robroek, University of Southampton, Laboratoire Ecologie Fonctionnelle et Environnement (ECOLAB), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Laboratoire des systèmes écologiques (ECOS), and Ecole Polytechnique Fédérale de Lausanne (EPFL)

Subjects
Vascular plant, Biogeochemical cycle, Peat, Plant functional types, 010504 meteorology & atmospheric sciences, [SDE.MCG]Environmental Sciences/Global Changes, Soil Science, Plant Science, 01 natural sciences, Carbon cycle, chemistry.chemical_compound, Botany, Dissolved organic carbon, Dissolved organic matter chemistry, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Dissolved organic matter chemistry, Enzymatic activity, FDA, FT-IR, Plant functional types, Plant-soil interactions, Sphagnum-dominated peatlands, Enzymatic activity, Plant-soil interactions, biology, Fluorescein diacetate hydrolysis, Soil organic matter, fungi, Ambientale, food and beverages, 04 agricultural and veterinary sciences, Mineralization (soil science), 15. Life on land, biology.organism_classification, FT-IR, Sphagnum-dominated peatlands, chemistry, 13. Climate action, 040103 agronomy & agriculture, 0401 agriculture, forestry, and fisheries, FDA
Abstract

Northern peatlands are large repositories of carbon. Peatland vascular plant community composition has been functionally associated to a set of biogeochemical processes such as carbon cycling. Yet, we do not fully understand to what extent vascular plant functional types (PFTs) affect the quality of dissolved organic matter, and if there is any feedback on soil microbial activity. Using a longer-term plant removal experiment in a boreo-nemoral peatland in Southern Sweden, we relate the dominance of different vascular plant functional types (i.e. ericoids and graminoids) to the chemistry of the dissolved organic matter (DOM) and microbial enzymatic activities (fluorescein diacetate hydrolysis, FDA). Our results show that PFTs modifies the composition of DOM moieties, with a decrease of low molecular weight organic compounds after vascular plant removal. The decrease of enzymatic activity by up to 68 % in the plant removal plots suggests a reduction in DOM mineralization in the absence of vascular plants. Our results show that plant-derived low molecular organic compounds enhance peatland microbial activity, and suggest that an increase of vascular plant cover in response to climate change can potentially destabilize the OM in peatlands, leading to increased carbon losses.

Published
2015
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43. Predator-prey mass ratio drives microbial activity under dry conditions in Sphagnum peatlands

Author

Edward A. D. Mitchell, Geneviève Chiapusio, Alexandre Buttler, Monika Reczuga, Vincent E. J. Jassey, Sandra Słowińska, Mariusz Lamentowicz, Philippe Binet, Michał Słowiński, Daniel Gilbert, Matthieu Mulot, Bogdan H. Chojnicki, Laboratory of Wetland Ecology and Monitoring, Faculty of Geographical and Geological Sciences, Adam Mickiewicz University in Poznań (UAM), Department of Biogeography and Palaeontology, Faculty of Geographical and Geological Sciences, Faculty of Biology, Laboratory of Soil Biodiversity, Université de Neuchâtel (UNINE), Jardin Botanique de Neuchâtel, Swiss Federal Research Institute (WSL), Laboratory of System Ecology, School of Architecture, Civil and Environmental Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), Laboratoire Chrono-environnement (UMR 6249) (LCE), Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Centre National de la Recherche Scientifique (CNRS), Faculty of Environment Engineering and Spatial Management, Department of Meteorology, Poznan University of Life Sciences, Department of Geoecology and Climatology, Institute of Geography and Spatial Organization, Polska Akademia Nauk = Polish Academy of Sciences (PAN), Centre Alpin de Recherche sur les Réseaux Trophiques et Ecosystèmes Limniques (CARRTEL), Institut National de la Recherche Agronomique (INRA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry]), Laboratory of System Ecology School Architecture Civil and Environment Engineering, Laboratoire Ecologie Fonctionnelle et Environnement (LEFE), Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT), Narodowe Centrum Nauki 2015/19/N/NZ8/00172 NN306060940 2015/17/B/ST10/01656, French National Agency for Research ANR-07-VUL-010, Switzerland through the Swiss Contribution to the enlarged European Union PSPB-013/2010, Adam Mickiewicz University in Poznan (AMUP), Laboratoire Chrono-environnement - UFC (UMR 6249) (LCE), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Polish Academy of Sciences, Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut National de la Recherche Agronomique (INRA), Laboratoire Ecologie Fonctionnelle et Environnement (ECOLAB), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées, Laboratoire Chrono-environnement - CNRS - UBFC (UMR 6249) (LCE), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), and Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Biogeochemical cycle, Peat, tourbière, 010504 meteorology & atmospheric sciences, Biodiversité et Ecologie, phenoloxidase, Context (language use), drought, 01 natural sciences, Sphagnum, microbial activity, Biodiversity and Ecology, poor fen, phénoloxydase, Mire, Wetlands, body size, food web, protists, soil moisture, water table manipulation, activité microbienne, Testate amoebae, Ecology, Evolution, Behavior and Systematics, peatlands, 0105 earth and related environmental sciences, Nature and Landscape Conservation, Trophic level, sécheresse, 2. Zero hunger, Ecology, biology, 04 agricultural and veterinary sciences, 15. Life on land, biology.organism_classification, Food web, protiste, 13. Climate action, 040103 agronomy & agriculture, 0401 agriculture, forestry, and fisheries, Environmental science, [SDE.BE]Environmental Sciences/Biodiversity and Ecology
Abstract

Mid- to high-latitude peatlands are a major terrestrial carbon stock but become carbon sources during droughts, which are increasingly frequent as a result of climate warming. A critical question within this context is the sensitivity to drought of peatland microbial food webs. Microbiota drive key ecological and biogeochemical processes, but their response to drought is likely to impact these processes. Peatland food webs have, however, been little studied, especially the response of microbial predators. We studied the response of microbial predators (testate amoebae, ciliates, rotifers, and nematodes) living in Sphagnum moss carpet to droughts, and their influence on lower trophic levels and on related microbial enzyme activity. We assessed the impact of reduced water availability on microbial predators in two peatlands using experimental (Linje mire, Poland) and natural (Forbonnet mire, France) water level gradients, reflecting a sudden change in moisture regime (Linje), and a typically drier environment (Forbonnet). The sensitivity of different microbial groups to drought was size dependent; large sized microbiota such as testate amoebae declined most under dry conditions (-41% in Forbonnet and -80% in Linje). These shifts caused a decrease in the predator-prey mass ratio (PPMR). We related microbial enzymatic activity to PPMR; we found that a decrease in PPMR can have divergent effects on microbial enzymatic activity. In a community adapted to drier conditions, decreasing PPMR stimulated microbial enzyme activity, while in extreme drought experiment, it reduced microbial activity. These results suggest that microbial enzymatic activity resulting from food web structure is optimal only within a certain range of PPMR, and that different trophic mechanisms are involved in the response of peatlands to droughts. Our findings confirm the importance of large microbial consumers living at the surface of peatlands on the functioning of peatlands, and illustrate their value as early warning indicators of change.

Published
2018
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44. Sphagnum Species Modulate their Phenolic Profiles and Mycorrhizal Colonization of Surrounding Andromeda polifolia along Peatland Microhabitats

Author

Leslie A. Weston, Gilles Comte, Marie Laure Toussaint, Philippe Binet, Floriant Bellvert, Geneviève Chiapusio, Alexandre Buttler, Frédéric Delarue, Vincent E. J. Jassey, Centre Alpin de Recherche sur les Réseaux Trophiques et Ecosystèmes Limniques (CARRTEL), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut National de la Recherche Agronomique (INRA), Laboratoire Chrono-environnement - UFC (UMR 6249) (LCE), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Laboratoire Ecologie Fonctionnelle et Environnement (ECOLAB), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées, Laboratoire d'Ingénierie des Systèmes Biologiques et des Procédés (LISBP), Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut National de la Recherche Agronomique (INRA), Laboratoire d'Ecologie Microbienne - UMR 5557 (LEM), Centre National de la Recherche Scientifique (CNRS)-Ecole Nationale Vétérinaire de Lyon (ENVL)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de la Recherche Agronomique (INRA)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS), Graham Centre for Agricultural Innovation, Charles Sturt University, Milieux Environnementaux, Transferts et Interactions dans les hydrosystèmes et les Sols (METIS), École pratique des hautes études (EPHE)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Ecological Systems Laboratory ECOS, Ecole Polytechnique Fédérale de Lausanne (EPFL), Swiss Federal Institute for Forest, Snow and Avalanche Research WSL, French National Agency [ANR-07-VUL-010], Pays Montbeliard Agglomeration (France), Institut National de la Recherche Agronomique (INRA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry]), Laboratoire Chrono-environnement - CNRS - UBFC (UMR 6249) (LCE), Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Institut National de la Recherche Agronomique (INRA)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Ecole Nationale Vétérinaire de Lyon (ENVL), École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Swiss Federal Institute for Forest, Snow and Landscape Research WSL, ANR-07-VULN-0010,PEATWARM,Impact du réchauffement climatique sur la focntion de puits de carbone de l'ecosysteme tourbières à sphaignes.(2007), Laboratoire Chrono-environnement (UMR 6249) (LCE), Laboratoire Ecologie Fonctionnelle et Environnement (LEFE), Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT), Université de Lyon-Université de Lyon-Ecole Nationale Vétérinaire de Lyon (ENVL)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Centre National de la Recherche Scientifique (CNRS), MetaToul FluxoMet (TBI-MetaToul), MetaboHUB-MetaToul, MetaboHUB-Génopole Toulouse Midi-Pyrénées [Auzeville] (GENOTOUL), Université de Toulouse (UT)-Université de Toulouse (UT)-Ecole Nationale Vétérinaire de Toulouse (ENVT), Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-MetaboHUB-Génopole Toulouse Midi-Pyrénées [Auzeville] (GENOTOUL), Université de Toulouse (UT)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Toulouse Biotechnology Institute (TBI), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Toulouse Biotechnology Institute (TBI), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Charles Sturt University [Australia], École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)

Subjects
0106 biological sciences, Peat, tourbière, heathland, 01 natural sciences, Biochemistry, Sphagnum, Plant Roots, peatland microhabitats, Soil, Abundance (ecology), bryophytes, Mycorrhizae, plant soil-interactions, Colonization, Mycorrhiza, Chromatography, High Pressure Liquid, Principal Component Analysis, biology, plants, 04 agricultural and veterinary sciences, General Medicine, carbon loss, Sphagnum magellanicum, symbiosis, Sphagnum fallax, phenolic profiles, gradient, mycorrhizal colonization, mycorhize, Ericaceae, Seasons, Ericaceous Andromeda polifolia, substrat de mousse de sphaigne, Spectrometry, Mass, Electrospray Ionization, mycorrhiza, Phenols, evolution, Botany, Sphagnopsida, global change, Ecology, Evolution, Behavior and Systematics, Allelopathy, Ecosystem, peatlands, Water, 15. Life on land, Sphagnum mosses, biology.organism_classification, allelopathy, responses, 040103 agronomy & agriculture, 0401 agriculture, forestry, and fisheries, profil phénolique, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, 010606 plant biology & botany
Abstract

Sphagnum mosses mediate long-term carbon accumulation in peatlands. Given their functional role as keystone species, it is important to consider their responses to ecological gradients and environmental changes through the production of phenolics. We compared the extent to which Sphagnum phenolic production was dependent on species, microhabitats and season, and how surrounding dwarf shrubs responded to Sphagnum phenolics. We evaluated the phenolic profiles of aqueous extracts of Sphagnum fallax and Sphagnum magellanicum over a 6-month period in two microhabitats (wet lawns versus dry hummocks) in a French peatland. Phenolic profiles of water-soluble extracts were measured by UHPLC-QTOF-MS. Andromeda polifolia mycorrhizal colonization was quantified by assessing the intensity of global root cortex colonization. Phenolic profiles of both Sphagnum mosses were species-, season- and microhabitat- dependant. Sphagnum-derived acids were the phenolics mostly recovered; relative quantities were 2.5-fold higher in S. fallax than in S. magellanicum. Microtopography and vascular plant cover strongly influenced phenolic profiles, especially for minor metabolites present in low abundance. Higher mycorrhizal colonization of A. polifolia was found in lawns as compared to hummocks. Mycorrhizal abundance, in contrast to environmental parameters, was correlated with production of minor phenolics in S. fallax. Our results highlight the close interaction between mycorrhizae such as those colonizing A. polifolia and the release of Sphagnum phenolic metabolites and suggest that Sphagnum-derived acids and minor phenolics play different roles in this interaction. This work provides new insight into the ecological role of Sphagnum phenolics by proposing a strong association with mycorrhizal colonization of shrubs.

Published
2018
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45. Reconstructing climate change and ombrotrophic bog development during the last 4000years in northern Poland using biotic proxies, stable isotopes and trait-based approach

Author

Mariusz Gałka, Norbert Kühl, Mariusz Lamentowicz, Vincent E. J. Jassey, Milena Obremska, Łukasz Lamentowicz, Andreas Lücke, Department of Biogeography and Paleoecology, Adam Mickiewicz University in Poznań (UAM), and Swiss Federal Institute for Forest, Snow and Landscape Research WSL

Subjects
010506 paleontology, geography, geography.geographical_feature_category, Peat, 010504 meteorology & atmospheric sciences, Ecology, [SDE.MCG]Environmental Sciences/Global Changes, Paleontology, Ombrotrophic, Climate change, Macrofossil, Vegetation, 15. Life on land, Oceanography, 01 natural sciences, 13. Climate action, Mire, 14. Life underwater, Testate amoebae, Bog, ComputingMilieux_MISCELLANEOUS, Ecology, Evolution, Behavior and Systematics, Geology, 0105 earth and related environmental sciences, Earth-Surface Processes
Abstract

article i nfo In this study, we present a record spanning the last 4000 years from a Baltic bog (Kusowskie Bagno) in northern Poland. Using numerous biotic and abiotic proxies, such as testate amoebae (depth to water table reconstruc- tions), stable carbon isotopes ( 13 C), plant macrofossils (proxies for local vegetation and mire surface wetness), pollen and spores (proxies for regional vegetation and human impact), we reconstructed and identified the re- gional hydro-climatic signal of Kusowskie Bagno bog and compared it to other bog records around the Baltic Sea. Our aims were to: 1) combine the species traits of bryophytes and testate amoebae, and more common proxies (isotopes, plant micro-and macro-remains) to infer past peatland development, 2) compare the hydro- climatic signal of Kusowskie Bagno bog to existing records around the Baltic Sea. We found that Kusowskie Bagno bog was very wet during the last 4000 years, and even drainage and peat exploitation had not disturbed its hydrology in northern part in the last 200 years. Carbon isotopes and plant macrofossils were significantly re- latedtospecifictraitsoftestateamoebae,whichinturnreflectedthewatertablechangesoverthelast4000years. Kusowskie Bagno recorded at least the following wet shifts: AD 250, 550, 850, 1250 and 1700, while wet condi- tions occurred during the Migration period at ca AD 550. Furthermore, the testate amoeba-based quantitative wetness reconstruction in Kusowskie Bagno bog resembles the pattern observed in other sites around the Baltic, i.e.,Estonia,Finland,Ireland,northernBritainandthe7500-yearrecordfromthe Stązkibog,northern Poland.Our results provided statistically validated evidence that interactions between plant and microbe need to be more considered further to reconstruct past hydrological. This is the first study of past hydro-climatic changes in peatlands based upon a trait-based approach.

Published
2015
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46. Impacts of tropospheric ozone exposure on peatland microbial consumers

Author

Vincent E. J. Jassey, Daniel Gilbert, Sylvia Toet, Mike Ashmore, Richard J. Payne, Laboratoire Chrono-environnement - CNRS - UBFC (UMR 6249) (LCE), Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Manchester Metropolitan University (MMU), Laboratoire Ecologie Fonctionnelle et Environnement (ECOLAB), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Chrono-environnement ( LCE ), Université Bourgogne Franche-Comté ( UBFC ) -Centre National de la Recherche Scientifique ( CNRS ) -Université de Franche-Comté ( UFC ), Manchester Metropolitan University ( MMU ), Laboratoire d’Ecologie Fonctionnelle, UMR 5245 (CNRS-UPS-INPT), Université P. Sabatier Toulouse III, and Université Paul Sabatier - Toulouse 3 ( UPS )

Subjects
Pollution, Peat, Ozone, 010504 meteorology & atmospheric sciences, media_common.quotation_subject, [SDE.MCG]Environmental Sciences/Global Changes, Air pollution, Soil Science, medicine.disease_cause, 01 natural sciences, Microbiology, [ SDE ] Environmental Sciences, chemistry.chemical_compound, Mire, medicine, Tropospheric ozone, Testate amoebae, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, media_common, Ecology, 04 agricultural and veterinary sciences, 15. Life on land, [ SDE.MCG ] Environmental Sciences/Global Changes, chemistry, 13. Climate action, [SDE]Environmental Sciences, 040103 agronomy & agriculture, 0401 agriculture, forestry, and fisheries, Environmental science, Terrestrial ecosystem
Abstract

Tropospheric ozone pollution is recognised as an important threat to terrestrial ecosystems but impacts on peatlands are little understood despite the importance of peat as a global carbon store. Here we investigate the impacts of three levels of elevated exposure to tropospheric ozone on peatland microbial communities with a particular focus on testate amoebae, the dominant microbial consumers. We found that in the intermediate (ambient + 25 ppb O3) and high treatments (ambient +35 ppb summer, +10 ppb year round) there were significant changes in testate amoeba communities, typified by an increase in abundance of Phyrganella spp. and loss of diversity. Phyrganella is often suggested to feed on fungi so the community change identified in our experiment might suggest that the testate amoeba response is at least partially mediated by interactions with other microbial groups. We do not find evidence for changes in numbers of undifferentiated microalgae, nematodes or rotifers but do find weak evidence for an increase in flagellates and ciliates. Our results provide the first direct data to show the impact of ozone on microbial consumers in peatlands.

Published
2017
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47. Vapor–pressure deficit and extreme climatic variables limit tree growth

Author

Vincent E. J. Jassey, Paula Sanginés de Cárcer, Alexandre Buttler, Yann Vitasse, Josep Peñuelas, Constant Signarbieux, Université de Neuchâtel (UNINE), Global Ecology Unit CREAF-CEAB-CSIC, Universitat Autònoma de Barcelona (UAB), Laboratoire Ecologie Fonctionnelle et Environnement (ECOLAB), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Laboratoire des systèmes écologiques (ECOS), Ecole Polytechnique Fédérale de Lausanne (EPFL), and Laboratory of Geographic Information Systems (LASIG), School of Architecture, Civil and Environmental Engineering (ENAC), École Polytechnique Fédérale de Lausanne (EPFL)

Subjects
0106 biological sciences, 010504 meteorology & atmospheric sciences, Vapor Pressure, Vapour Pressure Deficit, Climate Change, [SDE.MCG]Environmental Sciences/Global Changes, Wooded pastures, Climate change, Growing season, Forests, 01 natural sciences, Trees, Tree growth, Species Specificity, Effects of global warming, Fagus, Environmental Chemistry, Growth rate, Picea, Beech, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, General Environmental Science, Global and Planetary Change, Vapor-pressure deficit, Ecology, biology, fungi, Temperature, Extreme events, 15. Life on land, biology.organism_classification, Europe, Spruce, Productivity (ecology), 13. Climate action, Sustainability, Environmental science, Seasons, 010606 plant biology & botany
Abstract

Assessing the effect of global warming on forest growth requires a better understanding of species-specific responses to climate change conditions. Norway spruce and European beech are among the dominant tree species in Europe and are largely used by the timber industry. Their sensitivity to changes in climate and extreme climatic events, however, endangers their future sustainability. Identifying the key climatic factors limiting their growth and survival is therefore crucial for assessing the responses of these two species to ongoing climate change. We studied the vulnerability of beech and spruce to warmer and drier conditions by transplanting saplings from the top to the bottom of an elevational gradient in the Jura Mountains in Switzerland. We (1) demonstrated that a longer growing season due to warming could not fully account for the positive growth responses, and the positive effect on sapling productivity was species-dependent, (2) demonstrated that the contrasting growth responses of beech and spruce were mainly due to different sensitivities to elevated vapor-pressure deficits (VPD), (3) determined the species-specific limits to VPD above which growth rate began to decline, and (4) demonstrated that models incorporating extreme climatic events could account for the response of growth to warming better than models using only average values. These results support that the sustainability of forest trees in the coming decades will depend on how extreme climatic events will change, irrespective of the overall warming trend.

Published
2017
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48. Predator-prey mass ratio drives microbial activity under dry conditions in

Author

Monika K, Reczuga, Mariusz, Lamentowicz, Matthieu, Mulot, Edward A D, Mitchell, Alexandre, Buttler, Bogdan, Chojnicki, Michał, Słowiński, Philippe, Binet, Geneviève, Chiapusio, Daniel, Gilbert, Sandra, Słowińska, and Vincent E J, Jassey

Abstract

Mid- to high-latitude peatlands are a major terrestrial carbon stock but become carbon sources during droughts, which are increasingly frequent as a result of climate warming. A critical question within this context is the sensitivity to drought of peatland microbial food webs. Microbiota drive key ecological and biogeochemical processes, but their response to drought is likely to impact these processes. Peatland food webs have, however, been little studied, especially the response of microbial predators. We studied the response of microbial predators (testate amoebae, ciliates, rotifers, and nematodes) living in

Published
2017

49. Tipping point in plant-fungal interactions under severe drought causes abrupt rise in peatland ecosystem respiration

Author

Mariusz Lamentowicz, Edward A. D. Mitchell, Pierre Mariotte, Monika Reczuga, Luca Bragazza, Sandra Słowińska, Małgorzata Zielińska, Bogdan H. Chojnicki, Jan Barabach, Christophe V. W. Seppey, Enrique Lara, Alexandre Buttler, Michał Słowiński, Vincent E. J. Jassey, Bjorn J. M. Robroek, Laboratoire Ecologie Fonctionnelle et Environnement (ECOLAB), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Laboratory of Wetland Ecology and Monitoring, Faculty of Geographical and Geological Sciences, Adam Mickiewicz University, Department of Geoecology and Climatology, Institute of Geography and Spatial Organization, Polska Akademia Nauk = Polish Academy of Sciences (PAN), Laboratoire des systèmes écologiques (ECOS), Ecole Polytechnique Fédérale de Lausanne (EPFL), Laboratory of Soil Biology, Université de Neuchâtel (UNINE), Faculty of Environment Engineering and Spatial Management, Department of Meteorology, Poznan University of Life Sciences, Adam Mickiewicz University in Poznań (UAM), and Polish Academy of Sciences

Subjects
0106 biological sciences, Peat, 010504 meteorology & atmospheric sciences, Water table, 01 natural sciences, Sink (geography), Dissolved organic carbon, threshold, moving window structural equation model, Groundwater, Soil Microbiology, ComputingMilieux_MISCELLANEOUS, General Environmental Science, VDP::Mathematics and natural science: 400, biodiversity–ecosystem functioning, Global and Planetary Change, geography.geographical_feature_category, Ecology, food and beverages, plant–soil feedbacks, Plants, biodiversity–ecosystem functioning, ecosystem shifts, fungal diversity, hydrolases, moving window structural equation model, oxidases, plant–soil feedbacks, threshold, Droughts, oxidases, Ecosystem respiration, Cycling, Climate Change, [SDE.MCG]Environmental Sciences/Global Changes, hydrolases, 010603 evolutionary biology, Oxygen Consumption, ecosystem shifts, Environmental Chemistry, Ecosystem, Symbiosis, 0105 earth and related environmental sciences, geography, fungi, Fungi, technology, industry, and agriculture, Ambientale, Water, VDP::Matematikk og Naturvitenskap: 400, 15. Life on land, Water level, fungal diversity, 13. Climate action, Wetlands, Environmental science
Abstract

This is the peer reviewed version of the following article: Jassey, V. E. J., Reczuga, M. K., Zielinska, M., Slowinska, S., Robroek, B. J. M., Mariotte, P., ... Buttler, A. (2017) Tipping point in plant–fungal interactions under severe drought causes abrupt rise in peatland ecosystem respiration. Global Change Biology, 24(3), 972-98., which has been published in final form at https://doi.org/10.1111/gcb.13928. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. Ecosystems are increasingly prone to climate extremes, such as drought, with long‐lasting effects on both plant and soil communities and, subsequently, on carbon (C) cycling. However, recent studies underlined the strong variability in ecosystem's response to droughts, raising the issue of nonlinear responses in plant and soil communities. The conundrum is what causes ecosystems to shift in response to drought. Here, we investigated the response of plant and soil fungi to drought of different intensities using a water table gradient in peatlands—a major C sink ecosystem. Using moving window structural equation models, we show that substantial changes in ecosystem respiration, plant and soil fungal communities occurred when the water level fell below a tipping point of −24 cm. As a corollary, ecosystem respiration was the greatest when graminoids and saprotrophic fungi became prevalent as a response to the extreme drought. Graminoids indirectly influenced fungal functional composition and soil enzyme activities through their direct effect on dissolved organic matter quality, while saprotrophic fungi directly influenced soil enzyme activities. In turn, increasing enzyme activities promoted ecosystem respiration. We show that functional transitions in ecosystem respiration critically depend on the degree of response of graminoids and saprotrophic fungi to drought. Our results represent a major advance in understanding the nonlinear nature of ecosystem properties to drought and pave the way towards a truly mechanistic understanding of the effects of drought on ecosystem processes.

Published
2017
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50. Response to Editor to the comment by Delarue (2016) to our paper entitled ‘Persistent high temperature and low precipitation reduce peat carbon accumulation’

Author

Alexandre Buttler, Luca Bragazza, Vincent E. J. Jassey, Constant Signarbieux, Claudio Zaccone, Remy Albrecht, Bjorn J. M. Robroek, Laboratoire des systèmes écologiques (ECOS), Ecole Polytechnique Fédérale de Lausanne (EPFL), University of Southampton, Laboratoire Chrono-environnement - CNRS - UBFC (UMR 6249) (LCE), Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), and Laboratory of Geographic Information Systems (LASIG), School of Architecture, Civil and Environmental Engineering (ENAC), École Polytechnique Fédérale de Lausanne (EPFL)

Subjects
0106 biological sciences, Peat, 010504 meteorology & atmospheric sciences, Web of science, Earth science, [SDE.MCG]Environmental Sciences/Global Changes, chemistry.chemical_element, 01 natural sciences, Carbon Cycle, Soil, Environmental Chemistry, Precipitation, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, General Environmental Science, Global and Planetary Change, Ecology, 010604 marine biology & hydrobiology, Temperature, Carbon, chemistry, 13. Climate action, Wetlands, [SDE]Environmental Sciences, Environmental science
Abstract

Reference EPFL-ARTICLE-226456doi:10.1111/gcb.13559View record in Web of Science Record created on 2017-03-13, modified on 2017-11-20

Published
2017
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