HR: 1330h
AN: OS32A-0233    [PDF]
TI: Use of Thermocouple Arrays to Investigate the Environment Within Actively Forming Chimney Deposits, Guaymas Basin
AU: * Tivey, M K
EM: mktivey@whoi.edu
AF: Woods Hole Oceanographic Institution, 360 Woods Hole Rd., Woods Hole, MA 02543 United States
AU: Stakes, D S
AF: MBARI, 7700 Sandholt Rd., Moss Landing, CA 95039-9644 United States
AU: Bradley, A
AF: Woods Hole Oceanographic Institution, 360 Woods Hole Rd., Woods Hole, MA 02543 United States
AU: Seewald, J
AF: Woods Hole Oceanographic Institution, 360 Woods Hole Rd., Woods Hole, MA 02543 United States
AU: Wheat, C G
AF: Institute of Ocean Sciences, University of Alaska, Fairbanks, PO Box 757520, Fairbanks, AK 99775 United States
AU: Reysenbach, A
AF: Department of Biology, Portland State University, PO Box 751, Portland, OR 97201 United States
AU: Page, A
AF: Department of Biology, Portland State University, PO Box 751, Portland, OR 97201 United States
AU: Koski, R A
AF: Mail Stop 901, U.S. Geological Survey, 345 Middlefield Rd, Menlo Park, CA 94025 United States
AB: Four Ti-thermocouple arrays were deployed in March 2003 at 3 discrete vent structures in Guaymas Basin to trace the evolution of environments within newly formed chimney walls, and to determine the distribution of microorganisms within this temporal, chemical, thermal, and spatial framework. Temperatures were recorded as the thermocouples were enveloped during chimney growth. Upon recovery (after 4 and 72 days), the solid material (dominantly calcite and anhydrite) adjacent to each thermocouple was sub-sampled for molecular, chemical, and isotopic analyses. Final recorded temperatures within the 3 chimneys ranged from 110C to 303C. At a lower temperature, more hydrocarbon-rich vent site, thermocouples remained dominantly within warm flow and the small amount of material that formed around two of the thermocouples (that recorded maxima of 71C and 176C) washed away during recovery. Periodic (including diurnal) variability was observed in many of the temperature records including from inside the hottest channel (0.3C amplitude), within chimney walls (up to ~15C amplitude), and outside the structures. The within-structure periodic temperature variability likely reflects advection of cold fluid through the walls in response to pressure changes caused by strong bottom currents. Similar temperature variability within growing chimneys has been attributed to pressure changes caused by bottom currents at other vent sites, and provides evidence for walls being very permeable. Fluids exiting each structure were sampled and are being analyzed; the data will provide constraints for diffusive and advective transport models used to determine the chemical environment within chimney walls so that microbial populations can be placed in a unified chemical, thermal, and temporal context.
DE: 3015 Heat flow (benthic) and hydrothermal processes
DE: 3035 Midocean ridge processes
DE: 4832 Hydrothermal systems
DE: 8135 Hydrothermal systems (8424)
DE: 8424 Hydrothermal systems (8135)
SC: Ocean Sciences [OS]
MN: 2003 Fall Meeting