Filters: Tags: Thermokarst (X) > Extensions: Citation (X)
7 results (43ms)
Filters
Date Range
Types Contacts Categories Tag Types
|
Intensification of permafrost thaw has increased the frequency and magnitude of large permafrost slope disturbances (mega slumps) in glaciogenic terrain of northwestern Canada. Individual thermokarst disturbances up to 40 ha in area have made large volumes of previously frozen, highly weatherable fine-grained sediments available for leaching and transport to adjacent streams, significantly increasing sediment and solute loads in these systems. To test the effects of this climate-sensitive disturbance regime on the ecology of Arctic streams, we explored the relationship between physical and chemical variables and benthic macroinvertebrate communities in disturbed and undisturbed stream reaches in the Peel Plateau...
Categories: Publication;
Types: Citation;
Tags: Arctic streams,
benthic macroinvertebrate,
permafrost degradation,
sedimentation,
thaw slump,
We examined the effects of fire disturbance on permafrost degradation and thaw settlement across a series of wildfires (from ~1930 to 2010) in the forested areas of collapse-scar bog complexes in the Tanana Flats lowland of interior Alaska. Field measurements were combined with numerical modeling of soil thermal dynamics to assess the roles of fire severity and climate history in postfire permafrost dynamics. Field-based calculations of potential thaw settlement following the loss of remaining ice-rich permafrost averaged 0.6 m. This subsidence would cause the surface elevations of forests to drop on average 0.1 m below the surface water level of adjacent collapse-scar features. Up to 0.5 m of thaw settlement was...
Categories: Publication;
Types: Citation;
Tags: 0439 Ecosystems: structure and dynamics,
0475 Permafrost,
0702 Permafrost,
0708 Thermokarst,
and high-latitude processes,
Abstract (from http://onlinelibrary.wiley.com/doi/10.1111/gcb.12757/abstract): The landscape of the Barrow Peninsula in northern Alaska is thought to have formed over centuries to millennia, and is now dominated by ice-wedge polygonal tundra that spans drained thaw-lake basins and interstitial tundra. In nearby tundra regions, studies have identified a rapid increase in thermokarst formation (i.e., pits) over recent decades in response to climate warming, facilitating changes in polygonal tundra geomorphology. We assessed the future impact of 100 years of tundra geomorphic change on peak growing season carbon exchange in response to: (i) landscape succession associated with the thaw-lake cycle; and (ii) low, moderate,...
Categories: Publication;
Types: Citation;
Tags: Alaska CASC,
Data Visualization & Tools,
Science Tools for Managers,
arctic,
carbon balance,
We examined the effects of fire disturbance on permafrost degradation and thaw settlement across a series of wildfires (from ~1930 to 2010) in the forested areas of collapse-scar bog complexes in the Tanana Flats lowland of interior Alaska. Field measurements were combined with numerical modeling of soil thermal dynamics to assess the roles of fire severity and climate history in postfire permafrost dynamics. Field-based calculations of potential thaw settlement following the loss of remaining ice-rich permafrost averaged 0.6 m. This subsidence would cause the surface elevations of forests to drop on average 0.1 m below the surface water level of adjacent collapse-scar features. Up to 0.5 m of thaw settlement was...
Categories: Publication;
Types: Citation;
Tags: 0439 Ecosystems: structure and dynamics,
0475 Permafrost,
0702 Permafrost,
0708 Thermokarst,
and high-latitude processes,
This report describes the progress made by the Integrated Ecosystem Model (IEM) for Alaska and Northwest Canada Project for the full duration of the project (September 1, 2011 through August 31, 2016).This primary goal in this project was to develop the IEM modeling framework to integrate the driving components for and the interactions among disturbance regimes, permafrost dynamics, hydrology, and vegetation succession/migration for Alaska and Northwest Canada. The major activities of the project include (1) development and delivery of input data sets, (2) model coupling, (3) evaluation and applications of fire and vegetation dynamics, (4) evaluation and application of ecosystem carbon and energy balance, (5) evaluation...
Categories: Publication;
Types: Citation;
Tags: Alaska,
Alaska CASC,
Biogeochemistry,
Carbon Dioxide,
Climate Change,
Abstract (from http://onlinelibrary.wiley.com/doi/10.1002/2014JG002683/abstract): Changes in vegetation and soil properties following permafrost degradation and thermokarst development in peatlands may cause changes in net carbon storage. To better understand these dynamics, we established three sites in Alaska that vary in permafrost regime, including a black spruce peat plateau forest with stable permafrost, an internal collapse scar bog formed as a result of thermokarst, and a rich fen without permafrost. Measurements include year-round eddy covariance estimates of carbon dioxide (CO2 ), water, and energy fluxes, associated environmental variables, and methane (CH4 ) fluxes at the collapse scar bog. The ecosystems...
Categories: Publication;
Types: Citation;
Tags: Alaska CASC,
Alaska CASC,
Glaciers and Permafrost,
Water, Coasts and Ice,
black spruce,
Intensification of permafrost thaw has increased the frequency and magnitude of large permafrost slope disturbances (mega slumps) in glaciogenic terrain of northwestern Canada. Individual thermokarst disturbances up to 40 ha in area have made large volumes of previously frozen, highly weatherable fine-grained sediments available for leaching and transport to adjacent streams, significantly increasing sediment and solute loads in these systems. To test the effects of this climate-sensitive disturbance regime on the ecology of Arctic streams, we explored the relationship between physical and chemical variables and benthic macroinvertebrate communities in disturbed and undisturbed stream reaches in the Peel Plateau...
Categories: Publication;
Types: Citation;
Tags: Arctic streams,
benthic macroinvertebrate,
permafrost degradation,
sedimentation,
thaw slump,
|