Research Publications: UM-SG-RS-2020-15



Effects of resuspension of eastern oyster Crassostrea virginica biodeposits on phytoplankton community structure




Porter, ET; Robins, E; Davis, S; Lacouture, R; Cornwell, JC


Marine Ecology Progress Series
640 : 79 - 105




Anthropogenic disturbances in the Chesapeake Bay (USA) have depleted eastern oyster Crassostrea virginica abundance and altered the estuary's environment and water quality. Efforts to rehabilitate oyster populations are underway; however, the effect of oyster biodeposits on water quality and plankton community structure are not clear. In July 2017, we used 6 shear turbulence resuspension mesocosms (STURMs) to determine differences in plankton composition with and without the daily addition of oyster biodeposits to a muddy sediment bottom. STURM systems had a volume-weighted root mean square turbulent velocity of 1.08 cm s(-1), energy dissipation rate of similar to 0.08 cm(2) s(-3), and bottom shear stress of similar to 0.36-0.51 Pa during mixing-on periods during 4 wk of tidal resuspension. Phytoplankton increased their chlorophyll a content in their cells in response to low light in tanks with biodeposits. The diatom Skeletonema costatum bloomed and had significantly longer chains in tanks without biodeposits. These tanks also had significantly lower concentrations of total suspended solids, zooplankton carbon, and nitrite + nitrate, and higher phytoplankton carbon concentrations. Results suggest that the absence of biodeposit resuspension initiates nitrogen uptake for diatom reproduction, increasing the cell densities of S. costatum. The low abundance of the zooplankton population in non-biodeposit tanks suggests an inability of zooplankton to graze on S. costatum and negative effects of S. costaturn on zooplankton. A high abundance of the copepod Acartia tonsa in biodeposit tanks may have reduced S. costatum chain length. Oyster biodeposit addition and resuspension efficiently transferred phytoplankton carbon to zooplankton carbon, thus supporting the food web in the estuary.

Related Research Project(s) Funded by Maryland Sea Grant:

'Related Research Project(s)' link to details about research projects funded by Maryland Sea Grant that led to this publication. These details may include other impacts and accomplishments resulting from the research.

'Maryland Sea Grant Topic(s)' links to related pages on the Maryland Sea Grant website.

The Blue Crab: Callinectes Sapidus

An essential resource for researchers, students, and managers.  Get your copy today!

pile of cooked crabs