USAP-DC

Methane is a potent greenhouse gas that is naturally emitted into the oceans by geologic seeps and microbial production. Based on studies of persistent deep-sea seeps at mid- and northern latitudes, researchers have learned that bacteria and archaea can create a "sediment filter" that oxidizes methane prior to its release. Antarctica is thought to contain large reservoirs of organic carbon buried beneath its ice which could a quantity of methane equivalent to all of the permafrost in the Arctic and yet we know almost nothing about the methane oxidizing microbes in this region. How these microbial communities develop and potentially respond to fluctuations in methane levels is an under-explored avenue of research. A bacterial mat was recently discovered at 78 degrees south, suggesting the possible presence of a methane seep, and associated microbial communities. This project will explore this environment in detail to assess the levels and origin of methane, and the nature of the microbial ecosystem present.

An expansive bacterial mat appeared and/or was discovered at 78 degrees south in 2011. This site, near McMurdo Station Antarctica, has been visited since the mid-1960s, but this mat was not observed until 2011. The finding of this site provides an unusual opportunity to study an Antarctic marine benthic habitat with active methane cycling and to examine the dynamics of recruitment and community succession of seep fauna including bacteria, archaea, protists and metazoans. This project will collect the necessary baseline data to facilitate further studies of Antarctic methane cycling. The concentration and source of methane will be determined at this site and at potentially analogous sites in McMurdo Sound. In addition to biogeochemical characterization of the sites, molecular analysis of the microbial community will quantify the time scales on which bacteria and archaea respond to methane input and provide information on rates of community development and succession in the Southern Ocean. Project activities will facilitate the training of at least one graduate student and results will be shared at both local and international levels. A female graduate student will be mentored as part of this project and data collected will form part of her dissertation. Lectures will be given in K-12 classrooms in Oregon to excite students about polar science. National and international audiences will be reached through blogs and presentations at a scientific conference. The PI's previous blogs have been used by K-12 classrooms as part of their lesson plans and followed in over 65 countries.

Person	Role
Thurber, Andrew	Investigator and contact

Antarctic Organisms and Ecosystems

Award # 1642570

USAP-1642570_1

None in the Database

Repository	Title (link)	Format(s)	Status
BCO-DMO	Microbial community composition of the Cinder Cones Cold Seep	None	exist

1. Seabrook, S., C. De Leo, F., Baumberger, T., Raineault, N., & Thurber, A. R. (2018). Heterogeneity of methane seep biomes in the Northeast Pacific. Deep Sea Research Part II: Topical Studies in Oceanography, 150, 195–209. (doi:10.1016/j.dsr2.2017.10.016)
2. Thurber, A. R., Seabrook, S., & Welsh, R. M. (2020). Riddles in the cold: Antarctic endemism and microbial succession impact methane cycling in the Southern Ocean. Proceedings of the Royal Society B: Biological Sciences, 287(1931), 20201134. (doi:10.1098/rspb.2020.1134)
3. Thurber, A. (2019). Biogeochemical and sediment characteristics of the Cinder Cones Methane seep site in the Ross Sea from November 2016. Biological and Chemical Oceanography Data Management Office. (doi:10.1575/1912/bco-dmo.770638.1)
4. Galloway, A. W. E., Shanks, A. L., Groth, S., Marion, S. R., & Thurber, A. R. (2017). Massive crab recruitment events to the shallow subtidal zone. Ecology, 98(5), 1468–1470. (doi:10.1002/ecy.1740)
5. Thurber, A. (2019). Microbial community composition from 16s V4 region amplicon sequencing of the methane Seep at the Cinder Cones Cold Seep site, Nov 2016. Biological and Chemical Oceanography Data Management Office. (doi:10.1575/1912/bco-dmo.756997.1)