29 research outputs found
Relationship of methane consumption with the respiration of soil and grass-moss layers in forest ecosystems of the southern taiga in Western Siberia
The consumption of methane by some soils in the southern taiga of Western Siberia was studied by the static chamber method in the summer of 2013. The median of the specific CH4 flux through the soil was −0.05 mg C/(m2 h) for the entire set of measurements (the negative flux indicates the consumption of methane by the soil). A statistically significant (R2 = 0.81) linear relationship has been found between the specific CH4 flux to the soil and the total respiration of the soil and the grass-moss layers in the studied forest ecosystems. The quantitative theoretical explanation of this relationship is based on the plant-associated and free methanotrophy
A process-based model of methane consumption by upland soils
This study combines a literature survey and field observation data in an ad initio attempt to construct a process-based model of methane sink in upland soils including both the biological and physical aspects of the process. Comparison is drawn between the predicted sink rates and chamber measurements in several forest and grassland sites in the southern part of West Siberia. CH4 flux, total respiration, air and soil temperature, soil moisture, pH, organic content, bulk density and solid phase density were measured during a field campaign in summer 2014. Two datasets from literature were also used for model validation. The modeled sink rates were found to be in relatively good correspondence with the values obtained in the field. Introduction of the rhizospheric methanotrophy significantly improves the match between the model and the observations. The Q10 values of methane sink observed in the field were 1.2-1.4, which is in good agreement with the experimental results from the other studies. Based on modeling results, we also conclude that soil oxygen concentration is not a limiting factor for methane sink in upland forest and grassland ecosystems.Peer reviewe
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Northern Eurasia Future Initiative (NEFI): facing the challenges and pathways of global change in the 21st century
During the past several decades, the Earth system has changed significantly, especially across Northern Eurasia. Changes in the socio-economic conditions of the larger countries in the region have also resulted in a variety of regional environmental changes that can
have global consequences. The Northern Eurasia Future Initiative (NEFI) has been designed as an essential continuation of the Northern Eurasia Earth Science
Partnership Initiative (NEESPI), which was launched in 2004. NEESPI sought to elucidate all aspects of ongoing environmental change, to inform societies and, thus, to
better prepare societies for future developments. A key principle of NEFI is that these developments must now be secured through science-based strategies co-designed
with regional decision makers to lead their societies to prosperity in the face of environmental and institutional challenges. NEESPI scientific research, data, and
models have created a solid knowledge base to support the NEFI program. This paper presents the NEFI research vision consensus based on that knowledge. It provides the reader with samples of recent accomplishments in regional studies and formulates new NEFI science questions. To address these questions, nine research foci are identified and their selections are briefly justified. These foci include: warming of the Arctic; changing frequency, pattern, and intensity of extreme and inclement environmental conditions; retreat of the cryosphere; changes in terrestrial water cycles; changes in the biosphere; pressures on land-use; changes in infrastructure; societal actions in response to environmental change; and quantification of Northern Eurasia's role in the global Earth system. Powerful feedbacks between the Earth and human systems in Northern Eurasia (e.g., mega-fires, droughts, depletion of the cryosphere essential for water supply, retreat of sea ice) result from past and current human activities (e.g., large scale water withdrawals, land use and governance change) and
potentially restrict or provide new opportunities for future human activities. Therefore, we propose that Integrated Assessment Models are needed as the final stage of global
change assessment. The overarching goal of this NEFI modeling effort will enable evaluation of economic decisions in response to changing environmental conditions and justification of mitigation and adaptation efforts
Contribution of oxic methane production to surface methane emission in lakes and its global importance
Recent discovery of oxic methane production in sea and lake waters, as well as wetlands demands re-thinking of the global methane cycle and re-assessment of the contribution of oxic waters to atmospheric methane emission. Here we analysed system-wide sources and sinks of surface-water methane in a temperate lake. Using a mass balance analysis, we show that internal methane production in well-oxygenated surface water is an important source for surface-water methane during the stratified period. Combining our results and literature reports, oxic methane contribution to emission follows a predictive function of littoral sediment area and surface mixed layer volume. The contribution of oxic methane source(s) is predicted to increase with lake size, accounting for the majority (>50 %) of surface methane emission for lakes with surface areas >1 km2
Mapping of West Siberian taiga wetland complexes using Landsat imagery: implications for methane emissions
High-latitude wetlands are important for understanding climate change risks
because these environments sink carbon dioxide and emit methane. However,
fine-scale heterogeneity of wetland landscapes poses a serious challenge
when generating regional-scale estimates of greenhouse gas fluxes from point
observations. In order to reduce uncertainties at the regional scale, we
mapped wetlands and water bodies in the taiga zone of The West Siberia
Lowland (WSL) on a scene-by-scene basis using a supervised classification of
Landsat imagery. Training data consist of high-resolution images and
extensive field data collected at 28 test areas. The classification scheme
aims at supporting methane inventory applications and includes seven wetland
ecosystem types comprising nine wetland complexes distinguishable at the
Landsat resolution. To merge typologies, mean relative areas of wetland
ecosystems within each wetland complex type were estimated using
high-resolution images. Accuracy assessment based on 1082 validation
polygons of 10 × 10 pixel size indicated an overall map accuracy of
79 %. The total area of the WSL wetlands and water bodies was estimated to
be 52.4 Mha or 4–12 % of the global wetland area. Ridge-hollow complexes
prevail in WSL's taiga zone accounting for 33 % of the total wetland area,
followed by pine bogs or “ryams” (23 %), ridge-hollow-lake complexes
(16 %), open fens (8 %), palsa complexes (7 %), open bogs (5 %),
patterned fens (4 %), and swamps (4 %). Various oligotrophic
environments are dominant among wetland ecosystems, while poor fens cover
only 14 % of the area. Because of the significant change in the wetland
ecosystem coverage in comparison to previous studies, a considerable
reevaluation of the total CH4 emissions from the entire region is
expected. A new Landsat-based map of WSL's taiga wetlands provides a
benchmark for validation of coarse-resolution global land cover products and
wetland data sets in high latitudes
Relationship of methane consumption with the respiration of soil and grass-moss layers in forest ecosystems of the southern taiga in Western Siberia
The consumption of methane by some soils in the southern taiga of Western Siberia was studied by the static chamber method in the summer of 2013. The median of the specific CH4 flux through the soil was −0.05 mg C/(m2 h) for the entire set of measurements (the negative flux indicates the consumption of methane by the soil). A statistically significant (R2 = 0.81) linear relationship has been found between the specific CH4 flux to the soil and the total respiration of the soil and the grass-moss layers in the studied forest ecosystems. The quantitative theoretical explanation of this relationship is based on the plant-associated and free methanotrophy