Eel River Methane
Seeps Patterns of Infaunal Community Structure, Nutrition and Settlement Associated with an Upper Slope Methane Seep (with A. Rathburn, J. Gieskes) NOAA-NURP West Coast (3/00-2/02) The discovery of reduced environments in the deep sea, such as hydrothermal
vents and seeps, has had a dramatic influence on perception of life at
depth. However, most research into the structure and function of these
communities has emphasized larger (megafaunal) or hard-substrate organisms.
Paradigms formed about deep-sea reducing environments regarding community
structure, nutrition, and rates of colonization have yet to be examined
for smaller sediment-dwelling faunas (macrofauna, metazoan meiofauna,
and foraminifera). This project will establish the influence of methane
seep geochemistry on the community structure, nutritional sources and
settlement patterns of small infauna (macrofauna and meiofauna) on the
slope off the Eel River, Northern California. Coring will be conducted
to relate sediment geochemical properties to infaunal abundance, species
composition, diversity, and vertical distribution. The extent to which
reduced compounds, chemosynthesis, and symbioses contribute to the nutrition
of seep macrofauna (relative to non-seep slope fauna) will be examined
with stable isotopic analyses of C, N and S. The role of sulfides and
proximity to active seep sediments in determining infaunal recruitment
at seeps will be evaluated experimentally by deployment of sediment-filled
colonization trays. Resulting data on species composition and nutritional
modes of colonizers will help determine the extent to which the community
structure of seep infauna is determined by recruitment events. Finally,
recruitment patterns and infaunal communities of the Eel River methane
seeps will be compared to those in other stressed, enriched or more typical
slope environments. Together these results will help integrate the infauna
of reducing environments into the much larger context of deep-sea sediments
as a whole.
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Updated
September 7, 2006
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