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DISTRIBUTION AND ABUNDANCE OF BURROWING SHRIMP IN TWO OREGON ESTUARIES AND IMPLICATIONS FOR ESTUARINE-SCALE NITROGEN DYNAMICS
Citation:
DeWitt, T H. AND A. F. D'Andrea. DISTRIBUTION AND ABUNDANCE OF BURROWING SHRIMP IN TWO OREGON ESTUARIES AND IMPLICATIONS FOR ESTUARINE-SCALE NITROGEN DYNAMICS. Presented at Pacific Estuarine Research Society annual meeting, Vancouver, B.C., Canada, April 3-4, 2003.
Description:
Thalassinid burrowing shrimp (Neotrypaea californiensis and Upogebia pugettensis) inhabit large expanses of Pacific estuarine tide flats, from British Columbia to Baja California. The spatial distribution of shrimp populations within estuaries has rarely been quantified because of difficulty of quantitatively sampling these shrimp which burrow to 100 cm underground. To understand how burrowing shrimp affect estuarine-scale processes, we developed methods to rapidly estimate shrimp identity and abundance (using burrow opening architecture and density) and mapped populations of both species within the Yaquina River and Salmon River (OR) estuaries. Burrowing shrimp occupied >80% of the euryhaline and mesohaline intertidal flats in both estuaries, and covered >600 ha of tideflats over a distance of 17 km upriver in the Yaquina estuary. Aerial coverage for both species was similar within the Yaquina, though Upogebia dominated tideflats in the lower estuary and Neotrypaea dominated upriver. In contrast, Neotrypaea dominated >95% of the Salmon estuary tideflats and Upogebia was virtually absent. Coupling the population distribution data to nutrient flux measurements, we estimate that shrimp-dominated tideflats contribute 68-87% of total benthic efflux of DIN to the water column and are the second largest source of DIN to the water column during the summer (exceeded by the ocean).