This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).
Seafloor hHydrothermal vents that expel fluids with temperatures from ~2ºC to >400ºC, provide habitats for a diversity of microbes that subsist off geochemical fluxes from Earth's interior as opposed to making food from sunlight. Many vent micro-organisms feed off the energy from chemical disequilibria that results when reduced vent fluids interact and mix with oxic seawater on the seafloor. As a result hydrothermal vent chimneys form important and unusual habitats that sustain significant microbial diversity. This research combines microbial diversity data obtained in the field from vent deposits at the Ridge 2000, Lau Basin Integrated Study Site with computer calculations that represent the physical and geochemical environments from which the samples were taken. Both molecular finger printing data and a small subset of 454 (pyre) sequencing data (V6 region of the 16S reran gene) from hydrothermal chimney and flange deposits are combined with computer models of vent heat and mass transport to produce estimates of temperature gradients, pore fluid compositions, and local advection rates present in the chimneys and flanges. Measured exterior and interior vent chimney temperatures, mineral compositions and textures (including porosity) are used as constraints. The work helps improve our understanding of these unique and productive seafloor ecosystems. Broader impacts of the work include significant public outreach, student training, and support of two PIs whose gender is under-represented in the sciences.
