Home

Anantharaman

Poster Abstract Title: 
Genomic insights into deep-sea hydrothermal plumes
Authors and their affiliations: 
K. ANANTHARAMAN(1), R.A. LESNIEWSKI(1) and G.J. DICK(1)* 1. Dept. of Geological Sciences, University of Michigan, Ann Arbor, MI 48109, USA (*correspondence: gdick@umich.edu)

Hydrothermal plumes serve as important habitats for chemolithoautotrophic microbial communities that mediate the fate of hydrothermal inputs into the deep-sea. Although past studies have shown enhanced biological activity and biogeochemistry in hydrothermal plumes, little is known about the microorganisms involved.

Here we highlight the potential of metagenomics and metatranscriptomics for tracking microbiological and biogeochemical processes in plumes, and ultimately for advancing our understanding of the transfer of material from vents to oceans.

First, we report the analyses of microbial communities from the Guaymas Basin hydrothermal plume.  Assembly of ~2 million 454 Titanium metagenomic reads produced near complete genomes of SUP05-like gammaproteobacteria, Methylomonas-like gammaproteobacteria, SAR 324-like Deltaproteobacteria, and Crenarchaeota.  Analyses of ~3 million transcriptomic reads revealed 85% of them to be rRNA, which provides a deep view of the activity of different taxa. Additionally, comparison of protein-coding transcripts observed in plume and background highlighted  overabundance of transcripts encoding sulfur oxidation, electron transport proteins and a gene coding for a multi copper oxidase potentially involved in manganese(II) oxidation.

Second, we describe recently initiated work aimed at characterizing microbiology and geochemistry of rising hydrothermal plumes along the Eastern Lau Spreading Center.  Work is underway to use high-throughput pyrosequencing of 16S rRNA genes and metagenomics to reveal plume microbial community structure and potential function.  Integration of this data with geochemical and mineralogical analyses will provide insights into the co-evolution of microbiology and geochemistry in rising plumes of diverse geologic setting.

Overall, our results will seek to highlight the microorganisms present and active in hydrothermal plumes and determine their roles in plume biogeochemistry.

Contributions to Integration and Synthesis: 
We intend to use a combination of genomics, geochemistry, and mineralogy to study biotic-abiotic interactions, microbial mediation of biogeochemical reactions, particle formation and fate of hydrothermal inputs. Our work would integrate results from different vent sites along the Eastern lau spreading center representing a natural geochemical and lithological gradient and enable us to compare the geomicrobiology of the background deep-sea, sea floor and rising and neutrally buoyant plumes. While there have been a number of hydrothermal plume models, they solely incorporate abiotic interactions. To synthesize new findings of microbial processes and abiotic-biotic interactions in hydrothermal plumes, we are developing a hydrothermal plume model that couples hydrothermal fluid flow, mixing with ambient sea water, particle formation, biogeochemical reactions and microbial processes.