Lifting the Lid: Nitrifying Archaea Sustain Diverse Microbial Communities Below the Ross Ice Shelf
65 Pages Posted: 24 Sep 2020 Publication Status: Under ReviewMore...
The oceanic waters beneath Antarctica’s Ross Ice Shelf are among the largest unexplored habitats on Earth. Previous studies have shown active microorganisms reside in these waters, but their identity and capabilities remain unknown. Here, we combined multi-omics and biogeochemical measurements to determine the composition and metabolic activities of microbial communities in the water column under the Ross Ice Shelf. We reveal that these waters harbour diverse and distinct assemblages of microorganisms. In an ecosystem devoid of photosynthesis, the heterotrophic majority are largely sustained by highly active nitrifying archaea and bacteria (using ammonium from basal ice) and by other chemolitoautotrophs using reduced sulfur compounds. This suggests that chemolitoautotrophy is an important ecosystem driver in the waters below the RIS. Our data provide a valuable insight into the processes that sustain the largest sub-ice marine ecosystem, and will help predictions of the evolution of this system in a rapidly evolving climatic scenario.
Keywords: Ross Ice Shelf, microbes, diversity, function, biogeochemical cycles, under ice ecosystems
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