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Growing season CH4 fluxes were monitored over a two year period following the start of ecosystem-scale manipulations of water table position and surface soil temperatures in a moderate rich fen in interior Alaska. The largest CH4 fluxes occurred in plots that received both flooding (raised water table position) and soil warming, while the lowest fluxes occurred in unwarmed plots in the lowered water table treatment. A combination of treatment and soil hydroclimate variables explained more than 70% of the variation in ln-transformed CH4 fluxes, with mean daily water table position representing the strongest predictor. We used quantitative PCR of the -subunit of mcr operon to explore the influence of soil climate...
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To determine the influence of fire and thermokarst in a boreal landscape, we investigated peat cores within and adjacent to a permafrost collapse feature on the Tanana River Floodplain of Interior Alaska. Radioisotope dating, diatom assemblages, plant macrofossils, charcoal fragments, and carbon and nitrogen content of the peat profile indicate ~600 years of vegetation succession with a transition from a terrestrial forest to a sedge-dominated wetland over 100 years ago, and to a Sphagnum-dominated peatland in approximately 1970. The shift from sedge to Sphagnum, and a decrease in the detrended tree-ring width index of black spruce trees adjacent to the collapse coincided with an increase in the growing season temperature...
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To test the effects of altered hydrology on organic soil decomposition, we investigated CO2 and CH4 production potential of rich-fen peat (mean surface pH = 6.3) collected from a field water table manipulation experiment including control, raised and lowered water table treatments. Mean anaerobic CO2 production potential at 10 cm depth (14.1 ± 0.9 μmol C g−1 d−1) was as high as aerobic CO2 production potential (10.6 ± 1.5 μmol C g−1 d−1), while CH4 production was low (mean of 7.8 ± 1.5 nmol C g−1 d−1). Denitrification enzyme activity indicated a very high denitrification potential (197 ± 23 μg N g−1 d−1), but net NO 3 − reduction suggested this was a relatively minor pathway for anaerobic CO2 production. Abundances...
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The boreal forest contains large reserves of carbon. Across this region, wildfires influence the temporal and spatial dynamics of carbon storage. In this study, we estimate fire emissions and changes in carbon storage for boreal North America over the 21st century. We use a gridded data set developed with a multivariate adaptive regression spline approach to determine how area burned varies each year with changing climatic and fuel moisture conditions. We apply the process-based Terrestrial Ecosystem Model to evaluate the role of future fire on the carbon dynamics of boreal North America in the context of changing atmospheric carbon dioxide (CO2) concentration and climate in the A2 and B2 emissions scenarios of...
map background search result map search result map Scaling Uncertainties in Estimating Canopy Foliar Maintenance Respiration for Black Spruce Ecosystems in Alaska Land cover disturbances and feedbacks to the climate system in Canada and Alaska Effects of Experimental Water Table and Temperature Manipulations on Ecosystem CO2 Fluxes in an Alaskan Rich Fen Bacterial and enchytraeid abundance accelerate soil carbon turnover along a lowland vegetation gradient in interior Alaska Vulnerability of carbon storage in North American boreal forests to wildfires during the 21st century Changes in vegetation in northern Alaska under scenarios of climate change, 2003-2100: implications for climate feedbacks Modeling soil thermal and carbon dynamics of a fire chronosequence in interior Alaska Short-term response of methane fluxes and methanogen activity to water table and soil warming manipulations in an Alaskan peatland A dynamic organic soil biogeochemical model for simulating the effects of wildfire on soil environmental conditions and carbon dynamics of black spruce forests Wetland succession in a permafrost collapse: interactions between fire and thermokarst Exploring the sensitivity of soil carbon dynamics to climate change, fire disturbance and permafrost thaw in a black spruce ecosystem Exploring the sensitivity of soil carbon dynamics to climate change, fire disturbance and permafrost thaw in a black spruce ecosystem Response of anaerobic carbon cycling to water table manipulation in an Alaskan rich fen Assessment of boreal forest historical C dynamics in the Yukon River Basin: relative roles of warming and fire regime change Net emissions of CH4 and CO2 in Alaska: Implications for the region's greenhouse gas budget Planning for resilience: modeling change in human-fire interactions in the Alaskan boreal forest Exploring the sensitivity of soil carbon dynamics to climate change, fire disturbance and permafrost thaw in a black spruce ecosystem Effects of Experimental Water Table and Temperature Manipulations on Ecosystem CO2 Fluxes in an Alaskan Rich Fen Short-term response of methane fluxes and methanogen activity to water table and soil warming manipulations in an Alaskan peatland Wetland succession in a permafrost collapse: interactions between fire and thermokarst Response of anaerobic carbon cycling to water table manipulation in an Alaskan rich fen A dynamic organic soil biogeochemical model for simulating the effects of wildfire on soil environmental conditions and carbon dynamics of black spruce forests Scaling Uncertainties in Estimating Canopy Foliar Maintenance Respiration for Black Spruce Ecosystems in Alaska Exploring the sensitivity of soil carbon dynamics to climate change, fire disturbance and permafrost thaw in a black spruce ecosystem Bacterial and enchytraeid abundance accelerate soil carbon turnover along a lowland vegetation gradient in interior Alaska Assessment of boreal forest historical C dynamics in the Yukon River Basin: relative roles of warming and fire regime change Modeling soil thermal and carbon dynamics of a fire chronosequence in interior Alaska Planning for resilience: modeling change in human-fire interactions in the Alaskan boreal forest Changes in vegetation in northern Alaska under scenarios of climate change, 2003-2100: implications for climate feedbacks Net emissions of CH4 and CO2 in Alaska: Implications for the region's greenhouse gas budget Land cover disturbances and feedbacks to the climate system in Canada and Alaska Vulnerability of carbon storage in North American boreal forests to wildfires during the 21st century