Warming-induced reduced peat accrual rates and potential C losses in Northern U.S
Abstract
Peatlands located at northern latitudes represent a sink of carbon (C) that is at risk of being lost to the atmosphere if current and expected changes in climate accelerate existing C stock decomposition rates. The extent of such potential loss is still unknown, but recent studies suggest that accrual rate of this critical C stock may be in decline due to more rapid decomposition of plant material reaching the soil. The consequences for our climate system can be significant. If large amounts of C currently ';locked' belowground in peatland ecosystems were to be decomposed and hence lost to the atmosphere, atmospheric concentration of CO2 would increase, causing further warming and hence even more rapid decomposition of peatland C. Our objective in this study is to investigate and compare past and more recent rates of C accrual in peatlands to determine if the rates of C accrual are declining. We collected intact frozen blocks of peat from three sites in Northern Minnesota and sectioned them into horizontal slices, which are being dated by 137Cs and 14C. Atmospheric concentrations of both 137Cs and 14C spiked in the 1960's due to nuclear bomb testing, leaving a ';signature' in organic matter (14C) and sediments (137Cs). The signal has steadily declined since that time. Detection of the signal in current soil samples will allow us to date the sample and consequently to measure the quantity of C accrued in the peat over various measured time intervals.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2013
- Bibcode:
- 2013AGUFM.B53A0433F
- Keywords:
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- 0428 BIOGEOSCIENCES Carbon cycling;
- 0486 BIOGEOSCIENCES Soils/pedology;
- 0475 BIOGEOSCIENCES Permafrost;
- cryosphere;
- and high-latitude processes