HR: 0800h
AN: B21A-1009    [Abstracts]
TI: Mt. St. Helens: Influence of Magmatic Activity on the Biogeochemistry of Thermal Springs
AU: * Montross, S N
EM: smontross@montana.edu
AF: Montana State University, Department of Earth Sciences 200 Traphagen Hall, Bozeman, MT 59717 United States
AU: Skidmore, M
EM: skidmore@montana.edu
AF: Montana State University, Department of Earth Sciences 200 Traphagen Hall, Bozeman, MT 59717 United States
AU: Abrahamson, I S
EM: syverine@hotmail.com
AF: Montana State University, Department of Earth Sciences 200 Traphagen Hall, Bozeman, MT 59717 United States
AB: Mt St. Helens erupted explosively in 1980, and the intense heat of this event effectively sterilized the crater. The crater is filled with significant ash and volcanic debris and the crater environment has limited vegetation despite relatively abundant water, from rainfall and snowmelt. However, microorganisms thrive in the hot springs that have developed in the crater since the 1980 eruption in this otherwise biologically hostile environment. Channelized drainages exiting the crater contain numerous hot spring sources which result from thermal heating of meteoric water and gain solutes from water-rock interactions. These solutes are important inputs for the microbial communities found within the crater thermal systems. Water samples collected in August 2004 and August 2005 from thermal springs in Step Canyon allow the opportunity to assess the effects of recent magmatic activity in the crater since September 2004, on the aqueous chemistry and microbiology of thermal spring water. We have investigated the composition of microbial communities in crater hot spring ecosystems by identifying small subunit ribosomal RNA sequences amplified directly from extracted genomic DNA. Initial screening of cloned DNA (16S rRNA gene sequence) by restriction fragment length polymorphism and sequencing indicates moderate microbial diversity in this environment with representatives from the domains Bacteria and Archaea. The presentation will examine relationships between the aqueous geochemistry and the microbial communities and temporal changes in these related to the recent magmatic activity.
DE: 0414 Biogeochemical cycles, processes, and modeling (0412, 0793, 1615, 4805, 4912)
DE: 0448 Geomicrobiology
DE: 0450 Hydrothermal systems (1034, 3017, 3616, 4832, 8135, 8424)
DE: 8400 VOLCANOLOGY
SC: Biogeosciences [B]
MN: Fall Meeting 2005