Microbial regulation of greenhouse gas emissions from polar regions (OP2215)

Microbes are likely to play an increasingly important role in regulating Earth’s climate system (Falkowski et al., 2008, Science 320: 1034-1039) and are known to affect the carbon and nitrogen cycle of polar regions. In particular, microbes play important roles in the generation and decomposition of climate active gases, such as carbon dioxide (CO₂), methane (CH₄) and ozone-depleting substances (e.g. nitrous oxide, N₂O). Recent global increases in atmospheric CH₄ have been attributed to permafrost thaw and expansion of thermokarst lakes in the Arctic, while thickening of the permafrost active layer is thought to drive enhanced CO₂ emissions and destabilisation of underlying peat. However, current climate models do not take into account the response of microbial activity in polar regions, nor do they account for their role in cycling climate-relevant gases (Incorporating microbial processes into climate models, ASM report). To improve the predictive ability of climate models, it is important to understand the mechanisms by which microorganisms regulate greenhouse gas flux and to determine whether changes in microbial processes will lead to net positive or negative feedbacks on greenhouse gas emissions (Singh et al., 2010 Nature Reviews Microbiology 8: 779). This contribution has been particularly overlooked for the polar regions, where the environment has traditionally been considered too cold for significant microbial activity to occur. However, it is now clear that microbial presence is ubiquitous across the polar regions, and recent research points toward a potentially dynamic polar microbial community and with it, the possibility of significant microbial activity even under cold conditions, such as within the snowpack or in permafrost (Redeker et al., 2017 Journal of The Royal Society Interface 14: 20170729; Pearce et al., 2009 FEMS Microbiology Ecology 69: 143-157). The objective of this PhD is to understand how soil microbial processes in polar regions are likely to respond to climate warming, with a wider view towards developing better process-based models for simulating climate change feedbacks. This project will link to MicroArctic (Horizon 2020), the Greenland Circumnavigation Expedition (GLACE) and the Svalbard Integrated arctic Earth Observation System (SIOS). The PhD student will gain experience of microbial ecology, Arctic fieldwork, flux measurements, modelling and laboratory based simulations..