The effect of permafrost thaw on old carbon release and net carbon exchange from tundra Export

@article{citeulike:4697240, abstract = {Permafrost soils in boreal and Arctic ecosystems store almost twice as much carbon as is currently present in the atmosphere. Permafrost thaw and the microbial decomposition of previously frozen organic carbon is considered one of the most likely positive climate feedbacks from terrestrial ecosystems to the atmosphere in a warmer world. The rate of carbon release from permafrost soils is highly uncertain, but it is crucial for predicting the strength and timing of this carbon-cycle feedback effect, and thus how important permafrost thaw will be for climate change this century and beyond. Sustained transfers of carbon to the atmosphere that could cause a significant positive feedback to climate change must come from old carbon, which forms the bulk of the permafrost carbon pool that accumulated over thousands of years. Here we measure net ecosystem carbon exchange and the radiocarbon age of ecosystem respiration in a tundra landscape undergoing permafrost thaw to determine the influence of old carbon loss on ecosystem carbon balance. We find that areas that thawed over the past 15\&\#9;years had 40 per cent more annual losses of old carbon than minimally thawed areas, but had overall net ecosystem carbon uptake as increased plant growth offset these losses. In contrast, areas that thawed decades earlier lost even more old carbon, a 78 per cent increase over minimally thawed areas; this old carbon loss contributed to overall net ecosystem carbon release despite increased plant growth. Our data document significant losses of soil carbon with permafrost thaw that, over decadal timescales, overwhelms increased plant carbon uptake at rates that could make permafrost a large biospheric carbon source in a warmer world.}, author = {Schuur, Edward A. G. and Vogel, Jason G. and Crummer, Kathryn G. and Lee, Hanna and Sickman, James O. and Osterkamp, T. E.}, citeulike-article-id = {4697240}, citeulike-linkout-0 = {http://dx.doi.org/10.1038/nature08031}, citeulike-linkout-1 = {http://dx.doi.org/10.1038/nature08031}, day = {28}, doi = {10.1038/nature08031}, issn = {0028-0836}, journal = {Nature}, keywords = {boreal, carbon, climate, co2, ecosystem, emissions, fertilization, flux, observations, permafrost, tundra, vegetation}, month = {May}, number = {7246}, pages = {556--559}, posted-at = {2009-06-22 21:57:22}, priority = {2}, publisher = {Macmillan Publishers Limited. All rights reserved}, title = {The effect of permafrost thaw on old carbon release and net carbon exchange from tundra}, url = {http://dx.doi.org/10.1038/nature08031}, volume = {459}, year = {2009} }

TY - JOUR ID - citeulike:4697240 L3 - citeulike-article-id:4697240 N2 - Permafrost soils in boreal and Arctic ecosystems store almost twice as much carbon as is currently present in the atmosphere. Permafrost thaw and the microbial decomposition of previously frozen organic carbon is considered one of the most likely positive climate feedbacks from terrestrial ecosystems to the atmosphere in a warmer world. The rate of carbon release from permafrost soils is highly uncertain, but it is crucial for predicting the strength and timing of this carbon-cycle feedback effect, and thus how important permafrost thaw will be for climate change this century and beyond. Sustained transfers of carbon to the atmosphere that could cause a significant positive feedback to climate change must come from old carbon, which forms the bulk of the permafrost carbon pool that accumulated over thousands of years. Here we measure net ecosystem carbon exchange and the radiocarbon age of ecosystem respiration in a tundra landscape undergoing permafrost thaw to determine the influence of old carbon loss on ecosystem carbon balance. We find that areas that thawed over the past 15	years had 40 per cent more annual losses of old carbon than minimally thawed areas, but had overall net ecosystem carbon uptake as increased plant growth offset these losses. In contrast, areas that thawed decades earlier lost even more old carbon, a 78 per cent increase over minimally thawed areas; this old carbon loss contributed to overall net ecosystem carbon release despite increased plant growth. Our data document significant losses of soil carbon with permafrost thaw that, over decadal timescales, overwhelms increased plant carbon uptake at rates that could make permafrost a large biospheric carbon source in a warmer world. IS - 7246 JF - Nature SN - 0028-0836 EP - 559 TI - The effect of permafrost thaw on old carbon release and net carbon exchange from tundra PB - Macmillan Publishers Limited. All rights reserved VL - 459 SP - 556 KW - boreal KW - carbon KW - climate KW - co2 KW - ecosystem KW - emissions KW - fertilization KW - flux KW - observations KW - permafrost KW - tundra KW - vegetation AU - Schuur, Edward AU - Vogel, Jason AU - Crummer, Kathryn AU - Lee, Hanna AU - Sickman, James AU - Osterkamp, TE PY - 2009/05/28/ UR - http://dx.doi.org/10.1038/nature08031 ER -