PARTICLE-ASSOCIATED MICROBIAL COMMUNITY STRUCTURE AND METABOLISM AT ABYSSAL DEPTHS IN THE NORTH PACIFIC SUBTROPICAL GYRE.
The ocean acts as a sink in the global C cycle largely due to the export of organic matter to the deep-sea via sinking particles. However, very little is known about the exact microbial processes taking place on sinking particles at depth and how these processes impact ocean biogeochemistry. Thus, we set out to build a metagenomic and metatranscriptomic time-series capturing microbial community composition and activity on sinking particles from 4000 m at St. ALOHA from March to November 2014. Barophilic bacteria such as, Colwellia sp., Moritella sp., and Shewanella sp., and putatively microaerophilic Arcobacter sp., were the most transcriptionally active genera and were also the most abundant bacteria on average according to rRNA identities and metagenomic analyses. This suggests re-colonization of sinking particles by deep-sea bacteria as they were transported from the surface ocean to depth, as well as some contributions from animal-associated microbial species. Additionally, there was significant seasonal variability in the abundance of transcripts encoding carbohydrate active enzymes from Colwellia sp. and Arcobacter sp. suggestive of more organic matter degradation in Spring and Summer, relative to Fall. Lastly, meta’omic analyses revealed that eukaryotic groups including ciliates, pteropods, Rhizaria, and Cnidaria contributed significantly to POM at depth. These data provide new perspective on the origins, nature, and fate of sinking particles in the deep ocean, and unique insights into particle dynamics in situ. Ongoing parallel geochemical measurements will provide further biogeochemical perspective on the impact of particle-associated microbial communities.
Edwards, B. R., University of Hawaii - Manoa/ C-MORE, USA, email@example.com
Romano, A. E., University of Hawaii - Manoa/ C-MORE, USA, firstname.lastname@example.org
Eppley, J. M., University of Hawaii - Manoa/ C-MORE, USA, email@example.com
Clemente, T. M., University of Hawaii - Manoa/ C-MORE, USA, firstname.lastname@example.org
Karl, D. M., University of Hawaii - Manoa/ C-MORE, USA, email@example.com
DeLong, E. F., University of Hawaii - Manoa/ C-MORE, firstname.lastname@example.org
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