Pan-Arctic patterns of planktonic heterotrophic microbial abundance and processes: Controlling factors and potential impacts of warming

• Published in: Progress in Oceanography
• Main Authors: Maranger, R., Vaqué, Dolors, Nguyen, D., Hébert, Marie-Pier, Lara, Elena
• Other Authors: European Commission, Ministerio de Ciencia e Innovación (España)
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Elsevier 2015
• Subjects: Arctic; Arctic Ocean; Pacific; Sea ice
• Online Access: http://hdl.handle.net/10261/128605; https://doi.org/10.1016/j.pocean.2015.07.006; https://doi.org/10.13039/501100000780; https://doi.org/10.13039/501100004837

Special issue Overarching perspectives of contemporary and future ecosystems in the Arctic Ocean.-- 12 pages, 6 figures, 4 tables, 1 appendix supplementary material http://dx.doi.org/10.1016/j.pocean.2015.07.006.-- This work is a contribution to the Groupe de recherche interuniversitaire en limnologie et en environnement aquatique (GRIL) The Arctic Ocean is rapidly changing where increasing water temperatures and rapid loss of summer sea-ice will likely influence the structure and functioning of the entire ecosystem. The aim of this study was to synthesize the current state of knowledge on microbial abundances and processes from a regional Pan-Arctic perspective, characterize regulating factors and attempt to predict how patterns may change under a warming scenario. Here we identify some generalized patterns of different microbial variables between the Pacific-fed and the Atlantic-fed sectors of the Arctic Ocean. Bacterial production (BP), abundance and grazing rates by protists (GT) were all higher in the Atlantic-fed region. Bacterial loss by viral lyses (VL) was proportionally more important in the Pacific-fed sector, suggesting a reduced C transfer efficiency within the microbial loop of that region. Using a cross-comparative approach and all available data to build Arrhenius plots, we found a differential response to warming temperatures among various microbial processes. BP and GT responded similarly and more strongly to increases in temperature than VL did, suggesting a shift in the overall influence of viral mortality under a warming scenario. However, together with temperature, resource-related factors also exerted an influence in regulating these rates. We identified large information gaps for more classically studied microbial variable from several Arctic seas. Furthermore, there is limited information on less conventional pathways such as grazing by mixotrophic species, which may be playing a significant role in Arctic microbial trophodynamics. Although generalized patterns could be elucidated, ...