8 results on '"Anesio, Alexandre M."'
Search Results
2. Glacier clear ice bands indicate englacial channel microbial distribution.
- Author
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Varliero, Gilda, Holland, Alexandra, Barker, Gary L. A., Yallop, Marian L., Fountain, Andrew G., and Anesio, Alexandre M.
- Subjects
POLYNYAS ,MARKETING channels ,GLACIERS ,MELTWATER ,ICE cores ,MICROBIAL communities ,FREEZES (Meteorology) - Abstract
Distant glacial areas are interconnected by a complex system of fractures and water channels which run in the glacier interior and characterize the englacial realm. Water can slowly freeze in these channels where the slow freezing excludes air bubbles giving the ice a clear aspect. This ice is uplifted to the surface ablation zone by glacial movements and can therefore be observed in the form of clear surface ice bands. We employed an indirect method to sample englacial water by coring these ice bands. We were able, for the first time, to compare microbial communities sampled from clear (i.e. frozen englacial water bands) and cloudy ice (i.e. meteoric ice) through 16S rRNA gene sequencing. Although microbial communities were primarily shaped and structured by their spatial distribution on the glacier, ice type was a clear secondary factor. One area of the glacier, in particular, presented significant microbial community clear/cloudy ice differences. Although the clear ice and supraglacial communities showed typical cold-adapted glacial communities, the cloudy ice had a less defined glacial community and ubiquitous environmental organisms. These results highlight the role of englacial channels in the microbial dispersion within the glacier and, possibly, in the shaping of glacial microbial communities. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
3. Linkages between geochemistry and microbiology in a proglacial terrain in the High Arctic
- Author
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Wojcik, Robin, Donhauser, Johanna, Frey, Beat, Holm, Stine, Holland, Alexandra, Anesio, Alexandre M., Pearce, David A., Malard, Lucie, Wagner, Dirk, and Benning, Liane G.
- Subjects
biogeochemistry ,microbiology ,processes and landforms of glacial erosion ,biogeochemistry, glacial geomorphology, glacier chemistry, microbiology, processes and landforms of glacial erosion ,ddc:550 ,glacial geomorphology ,Institut für Geowissenschaften ,glacier chemistry - Abstract
Proglacial environments are ideal for studying the development of soils through the changes of rocks exposed by glacier retreat to weathering and microbial processes. Carbon (C) and nitrogen (N) contents as well as soil pH and soil elemental compositions are thought to be dominant factors structuring the bacterial, archaeal and fungal communities in the early stages of soil ecosystem formation. However, the functional linkages between C and N contents, soil composition and microbial community structures remain poorly understood. Here, we describe a multivariate analysis of geochemical properties and associated microbial community structures between a moraine and a glaciofluvial outwash in the proglacial area of a High Arctic glacier (Longyearbreen, Svalbard). Our results reveal distinct differences in developmental stages and heterogeneity between the moraine and the glaciofluvial outwash. We observed significant relationships between C and N contents, 13 C org and 15 N isotopic ratios, weathering and microbial abundance and community structures. We suggest that the observed differences in microbial and geochemical parameters between the moraine and the glaciofluvial outwash are primarily a result of geomorphological variations of the proglacial terrain.
- Published
- 2018
4. The microbiome of glaciers and ice sheets
- Author
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Anesio, Alexandre M., Lutz, Stefanie, Chrismas, Nathan A. M., and Benning, Liane G.
- Subjects
0301 basic medicine ,010504 meteorology & atmospheric sciences ,Earth science ,Biome ,Review Article ,01 natural sciences ,Applied Microbiology and Biotechnology ,Microbiology ,Microbial ecology ,03 medical and health sciences ,Cryoconite ,Glacial period ,Glaciers, Ice sheets, Microbiome ,0105 earth and related environmental sciences ,geography ,geography.geographical_feature_category ,Ecology ,QR100-130 ,Biogeochemistry ,Sediment ,Glacier ,Snow ,030104 developmental biology ,13. Climate action ,Environmental science ,Ice sheet ,Biotechnology - Abstract
Glaciers and ice sheets, like other biomes, occupy a significant area of the planet and harbour biological communities with distinct interactions and feedbacks with their physical and chemical environment. In the case of the glacial biome, the biological processes are dominated almost exclusively by microbial communities. Habitats on glaciers and ice sheets with enough liquid water to sustain microbial activity include snow, surface ice, cryoconite holes, englacial systems and the interface between ice and overridden rock/soil. There is a remarkable similarity between the different specific glacial habitats across glaciers and ice sheets worldwide, particularly regarding their main primary producers and ecosystem engineers. At the surface, cyanobacteria dominate the carbon production in aquatic/sediment systems such as cryoconite holes, while eukaryotic Zygnematales and Chlamydomonadales dominate ice surfaces and snow dynamics, respectively. Microbially driven chemolithotrophic processes associated with sulphur and iron cycle and C transformations in subglacial ecosystems provide the basis for chemical transformations at the rock interface under the ice that underpin an important mechanism for the delivery of nutrients to downstream ecosystems. In this review, we focus on the main ecosystem engineers of glaciers and ice sheets and how they interact with their chemical and physical environment. We then discuss the implications of this microbial activity on the icy microbiome to the biogeochemistry of downstream ecosystems.
- Published
- 2017
5. Linkages between geochemistry and microbiology in a proglacial terrain in the High Arctic.
- Author
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Wojcik, Robin, Donhauser, Johanna, Frey, Beat, Holm, Stine, Holland, Alexandra, Anesio, Alexandre M., Pearce, David A., Malard, Lucie, Wagner, Dirk, and Benning, Liane G.
- Subjects
GEOCHEMISTRY ,SOIL formation ,WEATHERING ,NITROGEN in soils ,HIGH Arctic regions - Abstract
Proglacial environments are ideal for studying the development of soils through the changes of rocks exposed by glacier retreat to weathering and microbial processes. Carbon (C) and nitrogen (N) contents as well as soil pH and soil elemental compositions are thought to be dominant factors structuring the bacterial, archaeal and fungal communities in the early stages of soil ecosystem formation. However, the functional linkages between C and N contents, soil composition and microbial community structures remain poorly understood. Here, we describe a multivariate analysis of geochemical properties and associated microbial community structures between a moraine and a glaciofluvial outwash in the proglacial area of a High Arctic glacier (Longyearbreen, Svalbard). Our results reveal distinct differences in developmental stages and heterogeneity between the moraine and the glaciofluvial outwash. We observed significant relationships between C and N contents, δ
13 Corg and δ15 N isotopic ratios, weathering and microbial abundance and community structures. We suggest that the observed differences in microbial and geochemical parameters between the moraine and the glaciofluvial outwash are primarily a result of geomorphological variations of the proglacial terrain. [ABSTRACT FROM AUTHOR]- Published
- 2019
- Full Text
- View/download PDF
6. Distribution of soil nitrogen and nitrogenase activity in the forefield of a High Arctic receding glacier.
- Author
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Turpin-Jelfs, Thomas, Michaelides, Katerina, Blacker, Joshua J., Benning, Liane G., Williams, James M., and Anesio, Alexandre M.
- Subjects
NITROGEN in soils ,GLACIERS ,GLOBAL warming ,SOIL formation ,SOIL texture - Abstract
Glaciers retreating in response to climate warming are progressively exposing primary mineral substrates to surface conditions. As primary production is constrained by nitrogen (N) availability in these emerging ecosystems, improving our understanding of how N accumulates with soil formation is of critical concern. In this study, we quantified how the distribution and speciation of N, as well as rates of free-living biological N fixation (BNF), change along a 2000-year chronosequence of soil development in a High Arctic glacier forefield. Our results show the soil N pool increases with time since exposure and that the rate at which it accumulates is influenced by soil texture. Further, all N increases were organically bound in soils which had been ice-free for 0–50 years. This is indicative of N limitation and should promote BNF. Using the acetylene reduction assay technique, we demonstrated that microbially mediated inputs of N only occurred in soils which had been ice-free for 0 and 3 years, and that potential rates of BNF declined with increased N availability. Thus, BNF only supports N accumulation in young soils. When considering that glacier forefields are projected to become more expansive, this study has implications for understanding how ice-free ecosystems will become productive over time. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
7. Linkages between geochemistry and microbiology in a proglacial terrain in the High Arctic
- Author
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Wojcik, Robin, Donhauser, Johanna, Frey, Beat, Holm, Stine, Holland, Alexandra, Anesio, Alexandre M., Pearce, David A., Malard, Lucie, Wagner, Dirk, and Benning, Liane G.
- Subjects
13. Climate action ,biogeochemistry ,microbiology ,processes and landforms of glacial erosion ,500 Naturwissenschaften und Mathematik::550 Geowissenschaften, Geologie::550 Geowissenschaften ,glacial geomorphology ,15. Life on land ,glacier chemistry - Abstract
Proglacial environments are ideal for studying the development of soils through the changes of rocks exposed by glacier retreat to weathering and microbial processes. Carbon (C) and nitrogen (N) contents as well as soil pH and soil elemental compositions are thought to be dominant factors structuring the bacterial, archaeal and fungal communities in the early stages of soil ecosystem formation. However, the functional linkages between C and N contents, soil composition and microbial community structures remain poorly understood. Here, we describe a multivariate analysis of geochemical properties and associated microbial community structures between a moraine and a glaciofluvial outwash in the proglacial area of a High Arctic glacier (Longyearbreen, Svalbard). Our results reveal distinct differences in developmental stages and heterogeneity between the moraine and the glaciofluvial outwash. We observed significant relationships between C and N contents, δ13Corg and δ15N isotopic ratios, weathering and microbial abundance and community structures. We suggest that the observed differences in microbial and geochemical parameters between the moraine and the glaciofluvial outwash are primarily a result of geomorphological variations of the proglacial terrain.
8. Microbial community dynamics in the forefield of glaciers.
- Author
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Bradley, James A., Singarayer, Joy S., and Anesio, Alexandre M.
- Subjects
GLACIAL microbiology ,BIOGEOCHEMISTRY ,MICROORGANISM populations ,MICROBIAL ecology ,METAGENOMICS - Abstract
Retreating ice fronts (as a result of a warming climate) expose large expanses of deglaciated forefield, which become colonized by microbes and plants. There has been increasing interest in characterizing the biogeochemical development of these ecosystems using a chronosequence approach. Prior to the establishment of plants, microbes use autochthonously produced and allochthonously delivered nutrients for growth. The microbial community composition is largely made up of heterotrophic microbes (both bacteria and fungi), autotrophic microbes and nitrogen-fixing diazotrophs. Microbial activity is thought to be responsible for the initial build-up of labile nutrient pools, facilitating the growth of higher order plant life in developed soils. However, it is unclear to what extent these ecosystems rely on external sources of nutrients such as ancient carbon pools and periodic nitrogen deposition. Furthermore, the seasonal variation of chronosequence dynamics and the effect of winter are largely unexplored. Modelling this ecosystem will provide a quantitative evaluation of the key processes and could guide the focus of future research. Year-round datasets combined with novel metagenomic techniques will help answer some of the pressing questions in this relatively new but rapidly expanding field, which is of growing interest in the context of future large-scale ice retreat. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
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