HR: 0800h
AN: B41A-0023    [Abstracts]
TI: An Assessment of Nutritional Sources of Organisms in a Temperate Coastal Marine System
AU: * Harbeson, S A
EM: sah2v@virginia.edu
AF: University of Virginia, Department of Environmental Sciences 291 McCormick Rd, Clark Hall P.O. Box 400123, Charlottesville, VA 22903, United States
AU: Macko, S A
EM: sam8f@virginia.edu
AF: University of Virginia, Department of Environmental Sciences 291 McCormick Rd, Clark Hall P.O. Box 400123, Charlottesville, VA 22903, United States
AB: The contribution of seagrass primary production to nutrient flow in temperate aquatic systems is widely debated. The purpose of this work was to verify that eelgrass ( Zostera marina) comprises a measurable fraction of the diet of consumers in recently restored eelgrass meadows. This investigation endeavored to quantify the nutritional contributions from primary producers to the aquatic food web of restored eelgrass beds in South Bay, Virginia, by monitoring the transfer of primary producer fatty acids to primary consumers and higher level consumers. Dominant primary producers, consumers, and higher trophic level fish were collected from eelgrass meadows and adjacent barren sediment habitats dominated by ephemeral floating macroalgae, mainly Ulva lactuca and Gracilaria spp. Bulk carbon, nitrogen, and sulfur isotope analysis of organisms at these sites indicated different sources of primary production, supporting the likelihood of distinct dietary compositions. Fatty acid profiles and relative concentrations of individual fatty acids in macrophytes differed among the species, allowing for source differentiation. The fatty acid composition of the tissues of macrophytes was compared to that of local consumers in an evaluation of the ultimate sources of dietary fatty acids. Particular attention was focused on the biomarker fatty acids found in eelgrass as well as other primary producers. The dietary importance of eelgrass to consumers in barren sediment sites is suggested to be negligible, resulting in fatty acid profiles differing from organisms captured at the two sites dominated by the macrophyte and seagrass primary producers.
DE: 0442 Estuarine and nearshore processes (4235)
DE: 0481 Restoration
DE: 0491 Food webs and trophodynamics (4817)
SC: Biogeosciences [B]
MN: 2007 Fall Meeting