Controls on Carbon and Methane flux Across a Complex Coastal Arctic Landscape

Principle Investigator: Dr. Walter C Oechel San Diego State University

Abstract:: This project will determine the climatic and other environmental controls and feedbacks on CO2 and methane flux of the Arctic Coastal tundra including drained thaw lake basins, polygons and inter-basin, non-polygonized tundra.
Two major objectives of this proposal will be: 1) Determine patterns of CO2 and methane flux with changes in vegetation, thaw depth, soil moisture, and water table depth of drained thaw lake basins (DTLB). 2) Determine the pattern of methane and CO2 flux of matrix or interstitial vegetation (i.e. that are found between lakes and/or DTLBs (Inter-basin tundra).

Location: Research activity will take place on the Barrow Peninsula, extending along the northern coast from Barrow Alaska, 300 km in the east and west direction and 200 km in the southern direction.

Hypotheses: Hypothesis 1: Drained lake basin age is the most reliable predictor of CO2 and methane flux due to a continuous sequestration of organic matter and transformation of this carbon into more recalcitrant form, slowing down the cycling of nutrients, plant productivity and mineralization. -Hypothesis 2: Polygonized tundra also makes up a substantial area of the coastal plains and move through a cycle from low, to high center polygon, and back. Water table depth will be the dominant predictor for CO2 and methane flux in these land surface types.

Methods: In this proposal, we will specifically characterize the CO2 and methane flux of the four major age classes of drained lake basins in the area replicated twice. By using portable eddy towers, we will measure CO2 and H2O flux and methane. Each DTLB will be measured for three days, allowing a return interval for a particular age and replicate of DTLB of 12. Ancillary thaw, LAI, soil organic matter, soil and plant nutrient content, and NDVI data along transects of the each DTLB will be made as well as ageing of the lakes.

Deliverables: We expect that the results from this funding will improve the scale of spatial estimates of current carbon flux values and enhance the predictability of how the change in magnitude, and sign of carbon flux will changes as driven by changes in climate. Deliverables include four papers; Controls and estimates of carbon flux of coastal tundra, Characterization of the carbon flux of a drained thaw lake basin chronosequence, Potential affects of climate change on carbon balance of polygonized ground; Methane flux in three major land surface types on the Artic coastal plain.

last updated: 15 April 2007 PLH