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Microbial community dynamics in a seasonally anoxic fjord: Saanich Inlet, British Columbia
Author(s) -
Zaikova Elena,
Walsh David A.,
Stilwell Claire P.,
Mohn William W.,
Tortell Philippe D.,
Hallam Steven J.
Publication year - 2010
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1111/j.1462-2920.2009.02058.x
Subject(s) - anoxic waters , water column , biogeochemical cycle , fjord , biology , hypoxia (environmental) , microbial population biology , ecology , oceanography , phylogenetic diversity , ecosystem , nutrient , nutrient cycle , environmental chemistry , oxygen , phylogenetic tree , geology , bacteria , gene , biochemistry , chemistry , genetics , organic chemistry
Summary Dissolved oxygen concentration plays a major role in shaping biotic interactions and nutrient flows within marine ecosystems. Throughout the global ocean, regions of low dissolved oxygen concentration (hypoxia) are a common and expanding feature of the water column, with major feedback on productivity and greenhouse gas cycling. To better understand microbial diversity underlying biogeochemical transformations within oxygen‐deficient oceanic waters, we monitored and quantified bacterial and archaeal community dynamics in relation to dissolved gases and nutrients during a seasonal stratification and deep water renewal cycle in Saanich Inlet, British Columbia, a seasonally anoxic fjord. A number of microbial groups partitioned within oxygen‐deficient waters including Nitrospina and SAR324 affiliated with the δ‐ proteobacteria , SAR406 and γ‐ proteobacteria related to thiotrophic gill symbionts of deep‐sea clams and mussels. Microbial diversity was highest within the hypoxic transition zone decreasing dramatically within anoxic basin waters and temporal patterns of niche partitioning were observed along defined gradients of oxygen and phosphate. These results provide a robust comparative phylogenetic framework for inferring systems metabolism of nitrogen, carbon and sulfur cycling within oxygen‐deficient oceanic waters and establish Saanich Inlet as a tractable model for studying the response of microbial communities to changing levels of water column hypoxia.