Implications of a changing Arctic on microbial communities: Following the effects of thawing permafrost from land to sea

• Published in: Environmental Microbiology
• Main Author: Müller, Oliver
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: The University of Bergen 2018
• Subjects: Klimaendringer; Marin mikrobiologi; Marine bakterier; Mikrobiell økologi; Permafrost; Arktis; https://data.ub.uio.no/realfagstermer/c030972; https://data.ub.uio.no/realfagstermer/c003160; https://data.ub.uio.no/realfagstermer/c003051; https://data.ub.uio.no/realfagstermer/c009111; https://data.ub.uio.no/realfagstermer/c013886; https://data.ub.uio.no/realfagstermer/c001406; VDP::Matematikk og Naturvitenskap: 400::Zoologiske og botaniske fag: 480::Marinbiologi: 497; Arctic; Arctic Ocean; Arctic microbes; Arktis*; Climate change; Ice; permafrost; Sea ice
• Online Access: https://hdl.handle.net/1956/18525

Climate change has severe impacts in the Arctic, where permafrost is thawing, glaciers are retreating and sea ice is melting. These physical changes are not only affecting large predators like polar bears, but also microscopic organisms such as Bacteria and Archaea. The impacts on microbes are far more concerning, as they are the main drivers of global biogeochemical cycles. Microbial-driven degradation of recently thawed permafrost organic matter is causing the release of critical greenhouse gases, including methane (CH4) and carbon dioxide (CO2). Parts of this formerly preserved organic carbon pool is upon thaw transported into marine systems, affecting the structure and dynamics of marine microbial communities. This thesis addresses the extensive implications of thawing permafrost on Arctic microbes. I investigated not only the microbial community composition and processes directly within the soil, but also the indirect effects of permafrost derived carbon run-off on the marine microbial structure, function and activity. By analyzing the microbial community composition, using high-throughput 16S rRNA gene sequencing, new insights on how microbial communities are structured in permafrost (Paper I), in a run-off affected fjord system (Paper II) and the Arctic Ocean (Paper IV and V) were revealed. 16S rRNA gene sequencing was also used to elucidate how permafrost derived organic matter affected the community structure and activity of coastal microbial communities (Paper III). Together, these results improve our understanding on how microbial community patterns can be used to explain biochemical processes like carbon degradation (Paper I, II, III and IV). We analyzed shifts in community composition due to climate change processes like permafrost thawing (Paper I) and carbon run-off (Paper III), thereby providing insights on which organisms and processes will be sensitive to the changes in a warmer Arctic. Permafrost is increasingly thawing, which will stimulate microbial activity, and subsequently cause the ...