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Unformatted text preview: season Water vapor and CO2 fluxes poorly coupled because water vapor exchange largely determined by evaporation from mosses and CO2 exchange controlled by vascular plant activity Permafrost Permafrost (permanently frozen ground) is a large carbon reservoir rarely incorporated into analysis of changes in global carbon reservoirs Yedoma is a type of permafrost comprised of 25% carbon and 5090% ice. Covers more than 1 million km2 of Siberia and Central Alaska Ground Temperature Profile Permafrost Estimate that carbon reservoir in frozen yedoma to be ~500Gt, another ~400Gt in nonyedoma permafrost, and 5070 Gt in peatlands Organic matter in Yedoma decomposes quickly when thawed resulting in respiration rates of 1040 g carbon/m3 initially and then 0.55g carbon/m3 per day over several years If these rates are sustained, most carbon will be released within a century Carbon in frozen yedoma is preserved for tens of thousands of years Yedoma carbon is decomposed by microbes under anaerobic conditions this produces methane During a lake freeze/thaw cycle associated with migration, ~30% of yedoma carbon is decomposed by microbes and converted to methane Permafrost Permafrost carbon is depleted in radiocarbon (14C) Methane, CO2, and DOC have radiocarbon age reflecting the time when the yedoma was formed in the glacial age This differentiates the permafrost carbon signal from other reservoirs Boreal Forest Boreal forest Boreal forest region occupies 1214 million km2 or 10% of vegetated...
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This note was uploaded on 11/07/2011 for the course EAS 8803 taught by Professor Staff during the Spring '08 term at Georgia Institute of Technology.
- Spring '08