COMMENTARY Microbial ecosystem responses to rapid climate change in the Arctic

• Main Author: Warwick F Vincent
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2010
• Subjects: Arctic; Arctic Ocean; Bering Sea; Simmonds; Climate change; Sea ice
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.468.2988; http://132.203.57.253/warwickvincent/PDFfiles/260.pdf

Rapid climate change in the Arctic has begun to affect the ecology of plants and animals throughout the region, with impacts on species ranges, popula-tion dynamics and food web interactions (Grebmeier et al., 2006; Post et al., 2009). By comparison, little attention has been given to the impacts on Arctic microbial communities, despite the major and often dominant contribution of microbes to total ecosys-tem biomass, biodiversity, nutrient cycling and energy flow. Some Arctic microbial ecosystems appear to be in rapid decline, whereas others are shifting towards new states, with implications for food webs and biogeochemical fluxes including greenhouse gas emissions. Given the accelerated rate of climate warming in the Arctic (Screen and Simmonds, 2010) and its potential effects on large-scale microbial processes (Kirchman et al., 2009; Schuur et al., 2009), Arctic microbiota can be viewed both as sentinels and amplifiers of global change. Ice forms the structural basis for many types of microbial ecosystem in the polar regions; small changes in temperature across the melting point can therefore have pronounced impacts on polar habi-tats and communities (Vincent, 1988). Global warm-ing is causing a general attrition of the cryosphere, the ensemble of ice-containing environments on Earth. The continuous decline in annual sea ice is reducing the growing season for microbial commu-nities that live in brine channels between the ice crystals and in the water column at the edge of the pack ice (marginal ice zone). In the Bering Sea region, these effects may account for decreased organic carbon fluxes to the seafloor and the observed reduction in benthic respiration rates (Grebmeier et al., 2006). Over the last decade, there has been a severe loss of multi-year sea ice, the 43-m thick ice formed by multiple years of accumulation. Only 20 years ago, this ice type covered about 80 % of the Arctic Ocean (time series details at