Hydrothermal Vent Fungal Communities and Their Putative Roles in Hydrocarbon Degradation at Guaymas Basin

Paraskevi Mara1, Gaetan Burgaud2, Gustavo A Ramirez3, Christopher M Reddy4, Sean Sylva5, David J. Beaudoin1, Andreas Teske6 and Virginia P Edgcomb7, (1)Woods Hole Oceanographic Institution, Woods Hole, MA, United States, (2)University of Brest, LUBEM (Laboratory of Biodiversity and Microbial Ecology), Plouzané, France, (3)University of North Carolina, United States, (4)WHOI, Woods Hole, MA, United States, (5)Woods Hole Science Center Woods Hole, Woods Hole, MA, United States, (6)Univ of North Carolina, Marine Science, Chapel Hill, United States, (7)Woods Hole Oceanographic Institution, Geology and Geophysics Department, Woods Hole, MA, United States
Although largely understudied, marine fungi are hypothesized to play a role in the biological carbon pump and in the chemistry of marine sediments. Their diversity and distribution in the marine subsurface, and specifically in hydrothermally-influenced and hydrocarbon-rich seep sediments remain unclear. iTAG data from hydrothermal sediment cores and cold control cores were collected by submersible Alvin during November 2018 from Guaymas Basin (Gulf of California). Amplicon sequence variants (ASVs) were used to describe the fungal diversity in different depth layers, and the potential influence of nutrients and temperature on the distribution of fungi at different sites. The iTAGs showed that the fungal diversity in the Guaymas Basin is dominated by unidentified ASVs and thus novel taxa. Samples from hydrocarbon-rich hydrothermal sediments of Guaymas Basin were also collected to identify ecological linkages and determine feedback patterns between hydrocarbon composition, fungal distribution, and biodegradation of specific hydrocarbons. GC x GC analyses revealed biodegradation of hydrocarbon substrates in these sediment cores. Cultured fungi are currently being tested for their ability to utilize and biodegrade different hydrocarbon (C10-C20) substrates.