Exploration of the microbial diversity and metabolic potential of ultra-deep trench sedimentary and water column environments in the Tonga Trench
Abstract
Exploration of the oceanic deep biosphere has expanded our understanding of such ecosystems including continental margins and mid-ocean ridges, but little is known about the deepest sites on Earth, oceanic trenches. In this study, sediment and water samples were collected from the Tonga Trench at 9100m below sea level. These include four water column samples at depths of 400m, 3000m, 5000m and ~9100m, and sediment samples at 0, 1, and 2 meter below the seafloor (mbsf). The analysis of the sediment samples provided a new perspective of life in the oceanic ultra-deep subsurface. The data for microbial community composition and metabolic profiles at 0 mbsf suggest that microbes are present and taxonomically similar to the deep water column microbes, and perform varied aerobic as well as anaerobic metabolisms, including degradation of organic carbon, oxidative phosphorylation, fermentation, nitrate reduction and sulfur oxidation. On the other hand, at 1 and 2 mbsf, the microbial community has diminished richness and diversity when compared to 0 mbsf and are potentially environmentally degraded due to rapid sedimentary deposition. The water samples varied from Archaea dominated at 400m, to over 90% Bacteria at 9000m. The 400m sample displays low oxygen metabolic signatures, while the mid water samples are the most similar to each other and possess aerobic metabolic signatures including archaeal ammonia oxidation. These analyzes allow for an unprecedented look of a largely understudied section of our planet
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.B53L2561L
- Keywords:
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- 0428 Carbon cycling;
- BIOGEOSCIENCES;
- 0448 Geomicrobiology;
- BIOGEOSCIENCES;
- 0456 Life in extreme environments;
- BIOGEOSCIENCES;
- 0463 Microbe/mineral interactions;
- BIOGEOSCIENCES