“Impacts of eddies on zooplankton community structure and biogeochemical
cycling in the Sargasso Sea”
Dr. Sara Goldthwaite
Virginia Institute of Marine Science
Monday, October 31, 2005
3:30 PM
Room 109, Crittenton Hall
Abstract
Recent evidence suggests that mesoscale eddies are an important mechanism of nutrient transport
in the oligotrophic waters of the main subtropical gyres. As mesozooplankton play a fundamental role
in food web interactions and flux of material out of the surface waters, changes in mesozooplankton
community composition due to physical perturbation by eddies could profoundly affect biogeochemical
cycling. We have quantified zooplankton biomass, vertical distribution, and contribution to particulate
flux across 2 distinct mesoscale features in the Sargasso Sea, namely a cold-core eddy and a mode water
eddy. We found enhanced biomass in the surface waters of both features relative to surrounding waters
and to a time-series at the historic Bermuda Atlantic Time-Series Study (BATS) site. However, the
mesozooplankton size class structure and horizontal distribution varied between the 2 eddies,
potentially due to differences in the community composition of primary producers. These mesoscale
features provide us with natural perturbation experiments in which the linkages between the physical
environment, the biota and biogeochemistry can be studied.
Biography
Sarah Goldthwaite received her bachelor’s degree at the University of California, Santa Cruz in 1995 and her
Ph.D. in Marine Science from the University of California, Santa Barbara in March 2004. In the interim period,
she spent 3 years working as a research technician on the BATS site at the Bermuda Biological Station. She is
currently a post-doctoral research associate with Dr. Deborah Steinberg at the Virginia Institute of Marine
Science and is working on the zooplankton component of an interdisciplinary project characterizing mesoscale
eddies in the Sargasso Sea. She has recently accepted an assistant professorship in the Department of
Oceanography at Humboldt State University in northern California.
Reception before seminar at 3:00 PM
Crittenton Hall
Old Dominion University
Norfolk, VA 23529
757-683-5548
Last updated 9/20/2005.
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