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Relationships among levels of benthic vegetation and pore-water sulfides, burrowing shrimp and infaunal amphipods in Yaquina estuary, Oregon
Citation:
YOUNG, D. R., J. O. LAMBERSON, AND R. S. Caldwell. Relationships among levels of benthic vegetation and pore-water sulfides, burrowing shrimp and infaunal amphipods in Yaquina estuary, Oregon. Presented at Pacific Estuarine Research Society Annual Meeting, Nanaimo, BC, CANADA, April 29 - May 01, 2010.
Impact/Purpose:
Benthic amphipods are an important component of estuarine food webs, which in turn support ecological services provided by near shore commercial and recreational fisheries.
Description:
Benthic amphipods are an important component of estuarine food webs, which in turn support ecological services provided by near shore commercial and recreational fisheries. In this study relationships among biological and geochemical aspects of the intertidal community were investigated. Transects within two major embayments of Yaquina estuary, extending from native eelgrass beds (Zostera marina) to the rocky shoreline were established. Percent cover and biomass values for eelgrass and benthic green macroalgae (Ulva spp.) were obtained regularly between 1999 and 2003. In 2000 an intensive study of benthic vegetation, sediment characteristics (grain size, temperature, salinity, nitrogen, organic carbon, pore-water sulfides) and infaunal crustaceans was conducted. Although eelgrass and macroalgal abundances at the two sites were similar, summer nitrogen and organic carbon levels were distinctly higher within the eelgrass meadow off Idaho Point. Pore-water sulfides along this transect, although highly variable, ranged to approx. 2000 μmoles per liter (μM), more than 200-fold the maximum measured along the opposing Coquille Pt. transect. Higher densities of burrowing shrimp holes occurred at the latter site, suggesting that the differences in pore-water sulfide might have resulted from greater bioturbation and bioirrigation of sediment and sulfide oxidation there. Benthic amphipod abundances decreased substantially when pore-water sulfides in cores collected mid-morning exceeded about 5 μM, and virtually no amphipods were observed at morning sulfide levels about 500 μM.