Soil microbial respiration in arctic soil does not acclimate to temperature

• Published in: Ecology Letters
• Main Authors: Hartley, Iain, Hopkins, David, Garnett, Mark H, Sommerkorn, Martin, Wookey, Philip
• Other Authors: Biological and Environmental Sciences, NERC Radiocarbon Facility (Environment), Macaulay Land Use Research Institute, orcid:0000-0001-5957-6424
• Format: Article in Journal/Newspaper
• Language: English
• Published: Blackwell Publishing 2008
• Subjects: Acclimation; Adaptation; Arctic; Carbon cycling; Climate change; CO2; Microbial community; Respiration; Soil; Temperature; Atmospheric carbon dioxide Environmental aspects; Global environmental change; Climatic changes Arctic regions; Climatic changes Environmental aspects
• Online Access: http://hdl.handle.net/1893/903; https://doi.org/10.1111/j.1461-0248.2008.01223.x; http://dspace.stir.ac.uk/bitstream/1893/903/2/Hartley2008revised.pdf; http://dspace.stir.ac.uk/bitstream/1893/903/1/Hartley2008revised.doc

Warming-induced release of CO2 from the large carbon (C) stores in arctic soils could accelerate climate change. However, declines in the response of soil respiration to warming in long-term experiments suggest that microbial activity acclimates to temperature, greatly reducing the potential for enhanced C losses. As reduced respiration rates with time could be equally caused by substrate depletion, evidence for thermal acclimation remains controversial. To overcome this problem, we carried out a cooling experiment with soils from arctic Sweden. If acclimation causes the reduction in soil respiration observed after experimental warming, then it should subsequently lead to an increase in respiration rates after cooling. We demonstrate that thermal acclimation did not occur following cooling. Rather, during the 90 days after cooling, a further reduction in the soil respiration rate was observed, which was only reversed by extended re-exposure to warmer temperatures. We conclude that over the time scale of a few weeks to months, warming-induced changes in the microbial community in arctic soils will amplify the instantaneous increase in the rates of CO2 production and thus enhance C losses potentially accelerating the rate of 21st century climate change.