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Rewetting combined with biomass crop cultivation (paludiculture) has been proposed as a method for reducing carbon dioxide (CO2) emissions from drained peatlands. This field experiment compared CO2 fluxes from drained (control) and rewetted experimental plots in a temperate fen under reed canary grass cultivation over two successive years. The annual weighted mean water table depth from soil surface (WTD) during the study period was 9, 3 and 1 cm in control, semi-flooded and flooded plots, respectively. There were no significant effects of WTD treatment on biomass yields. The choice of response model for CO2 fluxes influenced annual estimates of ecosystem respiration (ER) and gross primary production (GPP), but all models showed that ER and GPP decreased in response to rewetting. The resulting net ecosystem exchange (NEE) of CO2, derived by combining eight ER and eight GPP models, varied widely. For example, NEE (expressed as CO2-C) ranged from -935 to -208 g m(-2) yr(-1) for the flooded plots. One set of ER and GPP models was selected on the basis of statistical criteria and showed insignificant differences in NEE between the three water table treatments (-537 to -341 g CO2-C m(-2) yr(-1)). Treatment effects on CO2 emission factors, calculated as the sum of NEE and C export in harvested biomass (58-242 g CO2-C m(-2) yr(-1)), were similarly insignificant. Thus, the results indicated that varying WTD within this narrow range could influence both ER and GPP without altering the net emissions of CO2.

Tesis para obtener el grado de Magister Scientiae en Manejo y Conservación de Recursos Naturales para la Agricultura, orientación Agroecosistemas, de la Universidad Nacional de Mar del Plata, en agosto 2020. Las inundaciones constituyen procesos esenciales tal como lo son el flujo de energía y el ciclo de nutrientes, fundamentales en el mantenimiento de humedales y ecosistemas costeros. Sin embargo, cuando nos referimos a agroecosistemas, estas perturbaciones naturales causan efectos apreciables tanto sobre las comunidades vegetales y animales, como sobre los asentamientos urbano rurales presentes en la región, afectando la economía, el transporte y la infraestructura local asociada a los mismos. Particularmente en el caso del NE de La Pampa, durante los años 1999 y 2001, se registraron precipitaciones extraordinarias, que dieron lugar a situaciones de inundación y anegamiento severos afectando una importante superficie productiva. Otra situación similar ocurrió durante el otoño del año 2017. En este contexto de dinamismo constante del paisaje pampeano, las imágenes satelitales acopladas a un entorno SIG, proporcionan una herramienta adecuada para el estudio de la evolución de las áreas anegadas. Esta información sumada a otras capas permitiría desarrollar sistemas de prevención, seguimiento y evaluación a diferentes escalas espaciales y temporales. En la presente tesis se evaluó a través del análisis de imágenes satelitales, la dinámica de las inundaciones en las cuencas del departamento Maracó durante un período de 25 años, comprendido entre 1993-2017. Para completar el estudio se evaluaron registros de precipitaciones, niveles freáticos, excesos hídricos y uso de la tierra (uso consuntivo). Si bien la máxima superficie inundada ocurrió en la primavera del año 2001 para ambas cuencas, en la cuenca con tosca (“Oeste”) la superficie inundada en términos relativos fue superior en casi todo el período, situación muy evidente en el período de inundación 1999-2002 (excepto en la inundación 2016-2017 donde la cuenca “Este” resulta ser más afectada). Al menos dos son los factores que pueden explicar la diferencia de permanencia del agua en la superficie del suelo, entre las cuencas “Este” y “Oeste”: 1) la diferencia textural y, 2) la profundidad de la tosca. El análisis de correlación entre la lluvia caída 15, 30, 60 y 90 días antes de la fecha de la imagen satelital y la superficie inundada, presento mejor ajuste con la lluvia acumulada de 60 días, explicando un poco más del 50% de la ocurrencia de las inundaciones. Los datos de uso de la tierra indicaron una clara tendencia de aumento de la superficie destinada a cultivos, acompañada de una disminución de la superficie destinada a pasturas para ambas cuencas. Esto se ve reflejado en una disminución del uso consuntivo anual que realiza la vegetación. Es decir, el cambio en el uso de la tierra en los últimos años hacia especies que evapotranspiran menor cantidad de agua (dejando, por lo tanto, un volumen mayor disponible en el perfil del suelo), facilitan la posterior ocurrencia de inundaciones cuando se manifiestan las precipitaciones. Sin embargo, estos cambios fueron acompañados por una profundización de los niveles freáticos a través del tiempo, situación contraria a lo esperado Floods are essential processes such as energy flow and nutrient cycle, fundamental in the maintenance of wetlands and coastal ecosystems. However, when we refer to agroecosystems, these natural disturbances cause appreciable effects both on plant and animal communities, and on urban-rural settlements in the region, affecting the economy, transport and local infrastructure associated with them. Particularly in the case of the NE of La Pampa, during the years 1999 and 2001, extraordinary rainfalls were recorded, causing severe flooding and waterlogging situations, affecting an important productive area. Another similar situation occurred during the autumn of 2017. In this context of constant dynamism of the Pampean landscape, satellite images coupled with a GIS environment provide an adequate tool for studying the evolution of flooded areas. This information, added to other layers, would allow the development of prevention, monitoring and evaluation systems at different spatial and temporal scales. In this thesis the dynamics of floods in the basins of Maracó political district during a 25-year period (1993-2017), were evaluated through the analysis of satellite images. To complete the study, rainfall records, groundwater levels, water excesses and land use (consumptive use) were evaluated. Although the maximum flooded area occurred in the spring of 2001 for both basins, in the basin with rough (“West”) the flooded area in relative terms was higher in almost the entire period, situation more evident in the 1999-2002 flood period (except in the 2016-2017 flood where the “East” basin was more affected). At least two are the factors that can explain the difference in the permanence of water on the soil surface, between the “East” and “West” basins: 1) the textural difference and, 2) the depth of the rough. The correlation analysis between the fallen rain 15, 30, 60 and 90 days before the satellite image date and the flooded surface, presented a better adjustment with the accumulated rain of 60 days, explaining a little more than 50% of the occurrence of the floods. The land use data indicated a clear trend of increase in the area devoted to crops, accompanied by a decrease in the area devoted to pastures for both basins. This is reflected in a decrease in annual consumptive use by vegetation. That is, the change in land use in the recent years towards species that evapotranspire less amount of water (leaving a greater volume available in the soil profile), facilitate the subsequent occurrence of floods when excesive rainfall occurs. However, these changes were accompanied by a deepening of the water tables over time, a situation contrary to what was expected. EEA Anguil Fil: Carreño, Lorena Veronica. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Anguil; Argentina

We measured methane fluxes of a patterned bog situated in Siikaneva in southern Finland from six different plant community types in three growing seasons (2012–2014) using the static chamber method with chamber exposure of 35 min. A mixed-effects model was applied to quantify the effect of the controlling factors on the methane flux. The plant community types differed from each other in their water level, species composition, total leaf area (LAITOT) and leaf area of aerenchymatous plant species (LAIAER). Methane emissions ranged from −309 to 1254 mg m−2 d−1. Although methane fluxes increased with increasing peat temperature, LAITOT and LAIAER, they had no correlation with water table or with plant community type. The only exception was higher fluxes from hummocks and high lawns than from high hummocks and bare peat surfaces in 2013 and from bare peat surfaces than from high hummocks in 2014. Chamber fluxes upscaled to ecosystem level for the peak season were of the same magnitude as the fluxes measured with the eddy covariance (EC) technique. In 2012 and in August 2014 there was a good agreement between the two methods; in 2013 and in July 2014, the chamber fluxes were higher than the EC fluxes. Net fluxes to soil, indicating higher methane oxidation than production, were detected every year and in all community types. Our results underline the importance of both LAIAER and LAITOT in controlling methane fluxes and indicate the need for automatized chambers to reliably capture localized events to support the more robust EC method.

Wetlands are one of the most significant natural sources of methane (CH4) to the atmosphere. They emit CH4 because decomposition of soil organic matter in waterlogged anoxic conditions produces CH4, in addition to carbon dioxide (CO2). Production of CH4 and how much of it escapes to the atmosphere depend on a multitude of environmental drivers. Models simulating the processes leading to CH4 emissions are thus needed for upscaling observations to estimate present CH4 emissions and for producing scenarios of future atmospheric CH4 concentrations. Aiming at a CH4 model that can be added to models describing peatland carbon cycling, we composed a model called HIMMELI that describes CH4 build-up in and emissions from peatland soils. It is not a full peatland carbon cycle model but it requires the rate of anoxic soil respiration as input. Driven by soil temperature, leaf area index (LAI) of aerenchymatous peatland vegetation, and water table depth (WTD), it simulates the concentrations and transport of CH4, CO2, and oxygen (O2) in a layered one-dimensional peat column. Here, we present the HIMMELI model structure and results of tests on the model sensitivity to the input data and to the description of the peat column (peat depth and layer thickness), and demonstrate that HIMMELI outputs realistic fluxes by comparing modeled and measured fluxes at two peatland sites. As HIMMELI describes only the CH4-related processes, not the full carbon cycle, our analysis revealed mechanisms and dependencies that may remain hidden when testing CH4 models connected to complete peatland carbon models, which is usually the case. Our results indicated that (1) the model is flexible and robust and thus suitable for different environments; (2) the simulated CH4 emissions largely depend on the prescribed rate of anoxic respiration; (3) the sensitivity of the total CH4 emission to other input variables is mainly mediated via the concentrations of dissolved gases, in particular, the O2 concentrations that affect the CH4 production and oxidation rates; (4) with given input respiration, the peat column description does not significantly affect the simulated CH4 emissions in this model version., published version, peerReviewed

The Yamuna flood plains spread across the northern part of Indian subcontinent is home to millions of people. The ever-growing population in these plains make it difficult to sustain the demand of freshwater resources. However, the productive aquifers of flood plains could provide solution for these issues. In this context, it is necessary to understand the aquifer characteristics. Thus, the paper attempts to characterize the aquifer in Palla area of the flood plain using integrated approach. Besides, grain size analysis and site-litholog study, the nature of aquifer material was also ascertained from bulk mineralogy of the sediments using X-Ray Diffraction. The aquifer parameters were estimated with help of long duration pumping test data. Moreover, the effect of pumping on salinity variation and hydrochemical facies evolution was also examined. The sand dominant, unconfined aquifer was estimated to have horizontal hydraulic conductivity in the range of 25 m/day and vertical hydraulic conductivity of 6-7 m /day. While the specific yield of the aquifer was estimated in the range of 0.07-0.08. It is observed that under conducive active flood plain environment, the given sand mineralogy at the site does not allow salinity increase in groundwater even after more than a decade of groundwater pumping. In fact, over years, hydrochemical facies have evolved towards Bicarbonate type. These things put together make the active flood plain aquifer a sustainable groundwater resource.

We measured methane (CH4) exchange rates with automatic chambers at the forest floor of a nutrient-rich drained peatland in 2011–2013. The fen, located in southern Finland, was drained for forestry in 1969 and the tree stand is now a mixture of Scots pine, Norway spruce, and pubescent birch. Our measurement system consisted of six transparent chambers and stainless steel frames, positioned on a number of different field and moss layer compositions. Gas concentrations were measured with an online cavity ring-down spectroscopy gas analyzer. Fluxes were calculated with both linear and exponential regression. The use of linear regression resulted in systematically smaller CH4 fluxes by 10–45 % as compared to exponential regression. However, the use of exponential regression with small fluxes ( 4 m−2 h−1) typically resulted in anomalously large absolute fluxes and high hour-to-hour deviations. Therefore, we recommend that fluxes are initially calculated with linear regression to determine the threshold for low fluxes and that higher fluxes are then recalculated using exponential regression. The exponential flux was clearly affected by the length of the fitting period when this period was 4 flux: the forest floor acted as a CH4 sink particularly from early summer until the end of the year, while in late winter the flux was very small and fluctuated around zero. However, the magnitude of fluxes was relatively small throughout the year, ranging mainly from −130 to +100 µg CH4 m−2 h−1. CH4 emission peaks were observed occasionally, mostly in summer during heavy rainfall events. Diurnal variation, showing a lower CH4 uptake rate during the daytime, was observed in all of the chambers, mainly in the summer and late spring, particularly in dry conditions. It was attributed more to changes in wind speed than air or soil temperature, which suggest that physical rather than biological phenomena are responsible for the observed variation. The annual net CH4 exchange varied from −104 ± 30 to −505 ± 39 mg CH4 m−2 yr−1 among the six chambers, with an average of −219 mg CH4 m−2 yr−1 over the 2-year measurement period.

Permafrost soils and arctic wetlands methane emissions represent an important challenge for modeling the future climate. Here we present a process-based model designed to correctly represent the main thermal, hydrological, and biogeochemical processes related to these emissions for general land surface modeling. We propose a new multilayer soil carbon and gas module within the Interaction Soil-Biosphere-Atmosphere (ISBA) land-surface model (LSM). This module represents carbon pools, vertical carbon dynamics, and both oxic and anoxic organic matter decomposition. It also represents the soil gas processes for CH4, CO2, and O2 through the soil column. We base CH4 production and oxydation on an O2 control instead of the classical water table level strata approach used in state-of-the-art soil CH4 models. We propose a new parametrization of CH4 oxydation using recent field experiments and use an explicit O2 limitation for soil carbon decomposition. Soil gas transport is computed explicitly, using a revisited formulation of plant-mediated transport, a new representation of gas bulk diffusivity in porous media closer to experimental observations, and an innovative advection term for ebullition. We evaluate this advanced model on three climatically distinct sites : two in Greenland (Nuuk and Zackenberg) and one in Siberia (Chokurdakh). The model realistically reproduces methane and carbon dioxide emissions from both permafrosted and nonpermafrosted sites. The evolution and vertical characteristics of the underground processes leading to these fluxes are consistent with current knowledge. Results also show that physics is the main driver of methane fluxes, and the main source of variability appears to be the water table depth.

Permafrost peatlands are biogeochemical hot spots in the Arctic as they store vast amounts of carbon. Permafrost thaw could release part of these long-term immobile carbon stocks as the greenhouse gases (GHGs) carbon dioxide (CO 2 ) and methane (CH 4 ) to the atmosphere, but how much, at which time-span and as which gaseous carbon species is still highly uncertain. Here we assess the effect of permafrost thaw on GHG dynamics under different moisture and vegetation scenarios in a permafrost peatland. A novel experimental approach using intact plant–soil systems (mesocosms) allowed us to simulate permafrost thaw under near-natural conditions. We monitored GHG flux dynamics via high-resolution flow-through gas measurements, combined with detailed monitoring of soil GHG concentration dynamics, yielding insights into GHG production and consumption potential of individual soil layers. Thawing the upper 10–15 cm of permafrost under dry conditions increased CO 2 emissions to the atmosphere (without vegetation: 0.74 ± 0.49 vs. 0.84 ± 0.60 g CO 2 –C m −2 day −1 ; with vegetation: 1.20 ± 0.50 vs. 1.32 ± 0.60 g CO 2 –C m −2 day −1 , mean ± SD, pre- and post-thaw, respectively). Radiocarbon dating ( 14 C) of respired CO 2 , supported by an independent curve-fitting approach, showed a clear contribution (9%–27%) of old carbon to this enhanced post-thaw CO 2 flux. Elevated concentrations of CO 2 , CH 4 , and dissolved organic carbon at depth indicated not just pulse emissions during the thawing process, but sustained decomposition and GHG production from thawed permafrost. Oxidation of CH 4 in the peat column, however, prevented CH 4 release to the atmosphere. Importantly, we show here that, under dry conditions, peatlands strengthen the permafrost–carbon feedback by adding to the atmospheric CO 2 burden post-thaw. However, as long as the water table remains low, our results reveal a strong CH 4 sink capacity in these types of Arctic ecosystems pre- and post-thaw, with the potential to compensate part of the permafrost CO 2 losses over longer timescales.

Tropical peatlands are one of the most important terrestrial ecosystems in terms of impact on the atmospheric greenhouse gas composition. Currently, greenhouse gas emissions from tropical peatlands following disturbances due to deforestation, drainage or wildfire are substantial. We quantified in situ nitrous oxide (N2O) fluxes during both dry and wet seasons using a closed chamber method at sites that represented differing land uses and land use change intensities in Central Kalimantan, Indonesia. Cumulative N2O fluxes were compared with carbon dioxide (CO2) and methane (CH4) fluxes. The mean N2O flux rates (N2O-N &plusmn: SD, mg m−2 h−1) varied as follows: drained forest (0.112 ± 0.293) > agricultural peat at the Kalampangan site (0.012 ± 0.026) > drained burned peat (0.011 ± 0.018) > agricultural peat at the Marang site (0.0072 ± 0.028) > undrained forest (0.0025 ± 0.053) > clear-felled, drained, recovering forest (0.0022 ± 0.021). The widest N2O flux range was detected in the drained forest (max. 2.312 and min. −0.043 mg N2O-N m−2 h−1). At the other flux monitoring sites the flux ranges remained at about one tenth that of the drained forest site. The highest N2O emission rates were observed at water tables close to the peat surface where also the flux range was widest. Annual cumulative peat surface N2O emissions (expressed in CO2 equivalents as a percentage of the total greenhouse gas (N2O, CO2 and CH4) emissions) were 9.2 % at highest, but typically ~1 %. Average N2O fluxes and also the total of monitored GHG emissions were highest in drainage-affected forest which is characterized by continuous labile nitrogen availability from vegetation, and water tables typically below the surface.

Peatlands represent globally significant soil carbon stores that have been accumulating for millennia under water‐logged conditions. However, deepening water‐table depths (WTD) from climate change or human‐induced drainage could stimulate decomposition resulting in peatlands turning from carbon sinks to carbon sources. Contemporary WTD ranges of testate amoebae (TA) are commonly used to predict past WTD in peatlands using quantitative transfer function models. Here we present, for the first time, a study comparing TA‐based WTD reconstructions to instrumentally monitored WTD and hydrological model predictions using the MILLENNIA peatland model to examine past peatland responses to climate change and land management. Although there was very good agreement between monitored and modeled WTD, TA‐reconstructed water table was consistently deeper. Predictions from a larger European TA transfer function data set were wetter, but the overall directional fit to observed WTD was better for a TA transfer function based on data from northern England. We applied a regression‐based offset correction to the reconstructed WTD for the validation period (1931–2010). We then predicted WTD using available climate records as MILLENNIA model input and compared the offset‐corrected TA reconstruction to MILLENNIA WTD predictions over an extended period (1750–1931) with available climate reconstructions. Although the comparison revealed striking similarities in predicted overall WTD patterns, particularly for a recent drier period (1965–1995), there were clear periods when TA‐based WTD predictions underestimated (i.e. drier during 1830–1930) and overestimated (i.e. wetter during 1760–1830) past WTD compared to MILLENNIA model predictions. Importantly, simulated grouse moor management scenarios may explain the drier TA WTD predictions, resulting in considerable model predicted carbon losses and reduced methane emissions, mainly due to drainage. This study demonstrates the value of a site‐specific and combined data‐model validation step toward using TA‐derived moisture conditions to understand past climate‐driven peatland development and carbon budgets alongside modeling likely management impacts., We compared testate amoebae (TA)‐based water table (WTD) reconstructions to instrumentally monitored WTD and hydrological model predictions using the MILLENNIA peatland model to examine past peatland responses to climate change and potential grouse moor land management including drainage and rotational vegetation burning. The comparison of TA vs. MILLENNIA model and measured data revealed striking similarities in overall WTD patterns. However, there were clear periods when TA‐based predictions underestimated WTD. Importantly, simulated grouse moor management scenarios seemed to explain this period of drier TA WTD predictions, resulting in considerable model predicted carbon losses and reduced methane emissions, mainly due to drainage.

Minerotrophic fens and ombrotrophic bogs differ in their nutrient status, hydrology, vegetation and carbon dynamics, and their geographical distribution is linked to various climate parameters. Currently, bogs dominate the northern temperate and southern boreal zones but climate warming may cause a northwards shift in the distribution of the bog zone. To more profoundly understand the sensitivity of peatlands to changes in climate, we first used the plant macrofossil method to identify plant communities that are characteristic of past fen–bog transitions. These transitions were radiocarbon dated, to be linked to Holocene climate phases. Subsequently, palaeoecological data were combined with an extensive vegetation survey dataset collected along the current fen–bog ecotone in Finland where we studied how the distribution of the key plant species identified from peat records is currently related to the most important environmental variables. The fossil plant records revealed clear successional phases: an initial Carex-dominated fen phase, an Eriophorum vaginatum–dominated oligotrophic fen phase followed by an early bog phase with wet bog Sphagna. This was occasionally followed by a dry ombrotrophic bog phase. Timing of initiation and phase transitions, and duration of succession phases varied between three sites studied. However, the final ombrotrophication occurred during 2000–3000 cal. BP corresponding to the neoglacial cooling phase. Dry mid-Holocene seems to have facilitated initiation of Eriophorum fens. The peatlands surveyed in the fen–bog ecotone were classified into succession phases based on the key species distribution. In 33% of the studied peatlands, Sphagnum had taken over and we interpret they are going through a final transition from fen to bog. In addition to autogenic processes and direct climate impact, our results showed that ecosystem shifts are also driven by allogenic disturbances, such as fires, suggesting that climate change can indirectly assist the ombrotrophication process in the southern border of the fen–bog ecotone.

Sphagnum farming - the production of Sphagnum biomass on rewetted bogs - helps towards achieving global climate goals by halting greenhouse gas emissions from drained peat and by replacing peat with a renewable biomass alternative. Large-scale implementation of Sphagnum farming requires a wide range of know-how, from initial species selection up to the final production and use of Sphagnum biomass based growing media in horticulture. This article provides an overview of relevant knowledge accumulated over the last 15 years and identifies open questions.

Sphagnum farming - the production of Sphagnum biomass on rewetted bogs - helps towards achieving global climate goals by halting greenhouse gas emissions from drained peat and by replacing peat with a renewable biomass alternative. Large-scale implementation of Sphagnum farming requires a wide range of know-how, from initial species selection up to the final production and use of Sphagnum biomass based growing media in horticulture. This article provides an overview of relevant knowledge accumulated over the last 15 years and identifies open questions.

The Netherlands has a long history of soil research. Over the past 150 years, seven national soil maps have been produced at scales ranging from 1:50,000 to 1:1,000,000. The maps were based on different conceptual models which reflected advances in soil science as well as societal demands. There are four phases in the development of soil mapping in The Netherlands. The first three are: (i) the geological phase (1837–1937), (ii) the physiographic phase (1937–1962) and (iii) the morphometric phase (1962–1995). The earliest soil maps, made in the mid-1800s, were largely based on surface geology. In 1950 the first national soil map was published based on physiographic soil mapping. From the 1960s onwards, mapping followed a pedogenetic–morphometric approach and these maps have been widely used in land use planning, hydrologic studies, re-allotments, and agricultural land evaluations. An increase in environmental awareness with the need to assess environmental impacts and developments in information technology induced the digital soil information phase (1995–present). New technologies have improved the collection, storage, analysis and presentation of soil geographic information. It is concluded that initial soil mapping in The Netherlands had a strong agricultural focus but that the current maps are used in a wide range of applications.

International audience; Peatlands act as global sinks of atmospheric carbon (C) through the accumulation of organic matter(1), primarily made up of decay-resistant litter of peat mosses(2). However, climate warming has been shown to promote vascular plant growth in peatlands, especially ericaceous shrubs(3). A change in vegetation cover is in turn expected to modify above-ground/below-ground interactions(4), but the biogeochemical mechanisms involved remain unknown. Here, by selecting peatlands at different altitudes to simulate a natural gradient of soil temperature, we show that the expansion of ericaceous shrubs with warming is associated with an increase of polyphenol content in both plant litter and pore water. In turn, this retards the release of nitrogen (N) from decomposing litter, increases the amount of dissolved organic N and reduces N immobilization by soil microbes. A decrease of soil water content with increasing temperature promotes the growth of fungi, which feeds back positively on ericaceous shrubs by facilitating the symbiotic acquisition of dissolved organic N. We also observed a higher release of labile C from vascular plant roots at higher soil temperatures, which promotes the microbial investment in C-degrading enzymes. Our data suggest that climate-induced changes in plant cover can reduce the productivity of peat mosses and potentially prime the decomposition of organic matter by affecting the stoichiometry of soil enzymatic activity.

Forestry-drained peatlands in the boreal region are currently undergoing restoration in order to bring these ecosystems closer to their natural (undrained) state. Drainage affects the methane (CH4) dynamics of a peatland, often changing sites from CH4 sources to sinks. Successful restoration of a peatland would include restoration of not only the surface vegetation and hydrology, but also the microbial populations and thus CH4 dynamics. As a pilot study, CH4 emissions were measured on two pristine, two drained and three restored boreal spruce swamps in southern Finland for one growing season. Restoration was successful in the sense that the water table level in the restored sites was significantly higher than in the drained sites, but it was also slightly higher than in the pristine sites. The restored sites were surprisingly large sources of CH4 (mean emissions of 52.84 mg CH4 m(-2) d(-1)), contrasting with both the pristine (1.51 mg CH4 m(-2) d(-1)) and the drained sites (2.09 mg CH4 m-(2) d(-1)). More research is needed to assess whether the high CH4 emissions observed in this study are representative of restored spruce mires in general.

Hydrologic conditions are a major controlling factor for carbon exchange processes in high-latitude ecosystems. The presence or absence of water-logged conditions can lead to significant shifts in ecosystem structure and carbon cycle processes. In this study, we compared growing season CO2 fluxes of a wet tussock tundra ecosystem from an area affected by decadal drainage to an undisturbed area on the Kolyma floodplain in northeastern Siberia. For this comparison we found the sink strength for CO2 in recent years (2013–2015) to be systematically reduced within the drained area, with a minor increase in photosynthetic uptake due to a higher abundance of shrubs outweighed by a more pronounced increase in respiration due to warmer near-surface soil layers. Still, in comparison to the strong reduction of fluxes immediately following the drainage disturbance in 2005, recent CO2 exchange with the atmosphere over this disturbed part of the tundra indicate a higher carbon turnover, and a seasonal amplitude that is comparable again to that within the control section. This indicates that the local permafrost ecosystem is capable of adapting to significantly different hydrologic conditions without losing its capacity to act as a net sink for CO2 over the growing season. The comparison of undisturbed CO2 flux rates from 2013–2015 to the period of 2002–2004 indicates that CO2 exchange with the atmosphere was intensified, with increased component fluxes (ecosystem respiration and gross primary production) over the past decade. Net changes in CO2 fluxes are dominated by a major increase in photosynthetic uptake, resulting in a stronger CO2 sink in 2013–2015. Application of a MODIS-based classification scheme to separate the growing season into four sub-seasons improved the interpretation of interannual variability by illustrating the systematic shifts in CO2 uptake patterns that have occurred in this ecosystem over the past 10 years and highlighting the important role of the late growing season for net CO2 flux budgets.

International audience; Peatlands in the northern hemisphere have accumulated more atmospheric carbon (C) during the Holocene than any other terrestrial ecosystem, making peatlands long-term C sinks of global importance. Projected increases in nitrogen (N) deposition and temperature make future accumulation rates uncertain. * Here, we assessed the impact of N deposition on peatland C sequestration potential by investigating the effects of experimental N addition on Sphagnum moss. We employed meta-regressions to the results of 107 field experiments, accounting for sampling dependence in the data. * We found that high N loading (comprising N application rate, experiment duration, background N deposition) depressed Sphagnum production relative to untreated controls. The interactive effects of presence of competitive vascular plants and high tissue N concentrations indicated intensified biotic interactions and altered nutrient stochiometry as mechanisms underlying the detrimental N effects. Importantly, a higher summer temperature (mean for July) and increased annual precipitation intensified the negative effects of N. The temperature effect was comparable to an experimental application of almost 4 g N m)2 yr)1 for each 1°C increase. * Our results indicate that current rates of N deposition in a warmer environment will strongly inhibit C sequestration by Sphagnum-dominated vegetation.

For water levels, generally a non-stationary variable, the technique of universal kriging is applied in preference to ordinary kriging as the interpolation method. Each set of data in every sector can fit different empirical semivariogram models since they have different spatial structures. These models can be classified as circular, spherical, tetraspherical, pentaspherical, exponential, gaussian, rational quadratic, hole effect, K-bessel, J-bessel and stable. This study aims to determine which of these empirical semivariogram models will be best matched with the experimental models obtained from groundwater-table values collected from. Mustafakemalpasa left bank irrigation scheme in 2002. The model having the least error was selected by comparing the observed water-table values with the values predicted by empirical semivariogram models. It was determined that the rational quadratic empirical semivariogram model is the best fitted model for the studied irrigation area.

Проведено дослідження причин підтоплення 101 населеного пункту в трьох районах південного заходу Одеської області, визначено підтоплені і потенційно підтоплені території в межах кожного населеного пункту. В наслідок обробки отриманих даних були складені карти десятитисячного масштабу з зазначенням максимально можливих негативних явищ в межах кожного населеного пункту. Окрім цього вказані місця можливого затоплення частини території в наслідок повеней або значних опадів. Визначені основні причини наявності підтоплених і потенційно підтоплених територій в межах районів., Purpose. The study of reasons of under flooding of 101 settlements is conducted in three districts of south-west of the Odessa area. An aim hired consists of ground and drafting of databases (electronic and cartographic) impounded and potentially-impounded settlements of some districts of south-west of the Odessa area. A research object is settlements of three districts – Kiliya, Tarutino and Tatarbunar. The article of research is reasons of under flooding,along with the places of possible flood because of floods or other natural calamities.Methodology. The basic task of the carried out works was a receipt of reliable information, relatively impounded and potentially-impounded territories within the limits of settlements (SM) for the further acceptance of administrative decisions, in relation to each separate SM.Finding. In connection with absence of regime-observant network and some regime supervisions was worked out and applied approach which consisted of four stages. On results all stages regime-observant points were selected in which the annual watching is conducted a level and chemical composition of subsoil waters. Annual monitoring supervisions for the last ten years and generalization of their results allowed to make the maps of the territoriesimpounded and potentially impounded, distinguish the places of possible flood within the limits of every SM, to define principal reasons of presence of the territories impounded and potentially impounded within the limits of three districts.Results. The brought going over near the study of this problem allows more in detail to study and control the processes of under flooding in every settlement at the different degree of working out in detail., Проведено изучение причин подтопления 101 населённого пункта в трех районах юго-запада Одесской области, определены подтопленные и потенциально подтопленные территории в пределах каждого населенного пункта. По результатам обработки полученных данных были составлены карты десяти тысячного масштаба с указанием максимально возможных отрицательных явлений в пределах каждого населенного пункта. Указанны места возможного затопления части территории, вследствие наводнений или значительных осадков. Определенны основные причины наличия подтопленных и потенциально подтопленных территорий в пределах районов.

Розглядаються основні результати оцінки масштабів та інтенсивності трансформації природних ресурсів при експлуатації малих ГЕС із греблевою схемою генерації напору - Снятинської та Золотолипської ГЕС Прикарпатського регіону. На фоні існуючих об’єктів наводяться також дані по трансформації ресурсів в районі зведення нової ГЕС на р. Білий Черемош. Визначені перспективи освоєння гідроенергетичних ресурсів Прикарпаття шляхом будівництва та експлуатації греблевих ГЕС, які на відміну від дериваційних не призводять до значної трансформації природних ресурсів буферних територій., The basic results of estimation of scales and intensity of transformation of natural resources are examined during exploitation of the small HPS with the chart of generation of pressure rowing - Snatinskaya and Zolotolipskya the Prykarpattya region. On a background existent objects cited data also about transformation of resources in the district of erection new HPS to the r. White Cheremoh. The prospects of mastering of hydroenergetic resources of Prykarpattya are certain by building and exploitation of the pressure HPS that unlike derivation does not result in considerable transformation of natural resources of buffer territories.

Shallow water-tables strongly influence agro-ecosystems and pose difficult management challenges to farmers trying to minimize their negative effects on crops and maximize their benefits. In this paper, we evaluated how the water-table depth interacts with rainfall and sowing date to shape maize performance in the Western Pampas of Argentina. For this purpose, we analyzed the influence of water-table depth on the yields of 44 maize plots sown in early and late dates along eight growing seasons (2004-2012)that we rated as dry or wet. In addition, we characterized the influence of the water-table depth on intercepted radiation and crop water status by analyzing MODIS and Landsat images, respectively. The four conditions we evaluated (early sown-dry growing season, early-wet, late-dry, late-wet) showed similar yield response curves to water-table depth, with an optimum depth range (1.5-2.5 m) where yields were highest and stable (∼11.6 Mg ha−1on average). With water-table above this range, yields declined in all conditions at similar rates (p > 0.1), as well as the crop water status, as suggested by the Crop Water Stress Index, evidencing the negative effects of waterlogging. Water-tables deeper than the optimum range also caused declines of yield, intercepted radiation and crop water status, being these declines remarkably higher in early maize during dry seasons, evidencing a greater reliance of this condition on groundwater supply. Yield in areas with deep water-tables (>4 m) was significantly reduced to between a quarter and a half of yields observed in areas with optimum water-tables. Rainfall occurred around flowering had a strong impact on maize yield in areas with deep water-tables, but not in areas with optimum depth, where yields showed high temporal stability and independence from rainfall in that period. Our study confirmed the strong influence of water-table on rainfed maize and provides several guidelines to help farmers to take better decisions oriented to minimize hydrological risks and maximize the benefits of shallow water-tables. Fil: Florio, Eva Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi". Universidad Nacional de San Luis. Facultad de Ciencias Físico, Matemáticas y Naturales. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi"; Argentina Fil: Mercau, Jorge Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi". Universidad Nacional de San Luis. Facultad de Ciencias Físico, Matemáticas y Naturales. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi"; Argentina Fil: Jobbagy Gampel, Esteban Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi". Universidad Nacional de San Luis. Facultad de Ciencias Físico, Matemáticas y Naturales. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi"; Argentina Fil: Nosetto, Marcelo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi". Universidad Nacional de San Luis. Facultad de Ciencias Físico, Matemáticas y Naturales. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi"; Argentina. Universidad Nacional de Entre Ríos; Argentina

Soil can be either source or sink of methane (CH4), depending on the balance between methanogenesis and methanotrophy, which are determined by pedological, climatic and management factors. The objective of this study was to assess the impact of drainage of a highland Haplic Histosol on CH4 fluxes. Field research was carried out in Ponta Grossa (Paraná, Brazil) based on the measurement of CH4 fluxes by the static chamber method in natural and drained Histosol, over one year (17 sampling events). The natural Histosol showed net CH4 eflux, with rates varying from 238 µg m-2 h-1 CH4, in cool/cold periods, to 2,850 µg m-2 h-1 CH4, in warm/hot periods, resulting a cumulative emission of 116 kg ha-1 yr-1 CH4. In the opposite, the drained Histosol showed net influx of CH4 (-39 to -146 µg m-2 h-1), which resulted in a net consumption of 9 kg ha-1 yr-1 CH4. The main driving factors of CH4 consumption in the drained soil were the lowering of the water-table (on average -57 cm, vs -7 cm in natural soil) and the lower water content in the 0-10 cm layer (average of 5.5 kg kg-1, vs 9.9 kg kg-1 in natural soil). Although waterlogged Histosols of highland areas are regarded as CH4 sources, they fulfill fundamental functions in the ecosystem, such as the accumulation of organic carbon (581 Mg ha-1 C to a depth of 1 m) and water (8.6 million L ha-1 = 860 mm to a depth of 1 m). For this reason, these soils must not be drained as an alternative to mitigate CH4 emission, but effectively preserved. O solo pode atuar como fonte ou sumidouro de metano (CH4), dependendo do balanço entre metanogênese e metanotrofia, definido por fatores pedológicos, climáticos e de manejo. O objetivo deste estudo foi avaliar as implicações da drenagem do Organossolo Háplico hêmico, típico em campo hidrófilo de altitude sobre os fluxos de CH4. A pesquisa de campo foi conduzida no município de Ponta Grossa, PR, e envolveu avaliações de fluxos de CH4 pelo método da câmara estática em Organossolo natural e Organossolo drenado, por um período de um ano (17 coletas). No Organossolo natural, ocorreu efluxo líquido de CH4, com taxas variando entre 238 µg m-2 h-1 de CH4, em épocas mais frias, e 2.850 µg m-2 h-1 de CH4, em épocas mais quentes, totalizando emissão acumulada de 116 kg ha-1 ano-1 de CH4. Na área drenada, ocorreu influxo líquido (-39 a -146 µg m-2 h-1 de CH4), que totalizou em consumo de 9 kg ha-1 ano-1 de CH4. O rebaixamento do nível freático (em média -57 cm, contra -7 cm no solo natural) e a menor umidade gravimétrica na camada de 0-10 cm (média de 5,5 kg kg-1, contra 9,9 kg kg-1 do solo natural) foram os principais fatores determinantes do consumo de CH4, na área drenada. Apesar de os Organossolos em campo hidrófilo atuarem como fonte de CH4, esses possuem importantes funções no ecossistema, como acumular carbono orgânico (581 Mg ha-1 de C até 1 m) e armazenar água (8,6 milhões de L = 860 mm até 1 m). Por essa razão, não devem ser drenados, como alternativa para redução da emissão de metano, mas efetivamente preservados.