Department of Integrative Biology

Seagrasses and bivalves co-occur worldwide, and each plays a role in the structure, function, and services of coastal ecosystems. While seagrasses are declining, bivalve aquaculture is expanding, and impacts from culture practices, as opposed to the cultured organisms themselves, need to be distinguished. In 2 experiments, we tested the effects of live Crassostrea gigas, an introduced oyster, on Zostera marina, a native seagrass, in Willapa Bay, Washington. Expt 1 involved adult oyster addition across a large range in density (0 to 70% cover), and also considered the effects of the physical components of an oyster: its shell, and fertilizer mimicking biodeposition. Expt 2 simulated a crop cycle with addition of newly-settled oysters at relevant commercial density (