MEPS 341:293-298 (2007)  -  doi:10.3354/meps341293

Top-down control of phytoplankton by oysters in Chesapeake Bay, USA: Comment on Pomeroy et al. (2006)

Roger I. E. Newell1,*, W. Michael Kemp1, James D. Hagy III2, Carl F. Cerco3, Jeremy M. Testa1 , Walter R. Boynton4

1University of Maryland Center for Environmental Science, Horn Point Laboratory, PO Box 775, Cambridge, Maryland 21613, USA
2US Environmental Protection Agency, NHEERL, Gulf Ecology Division, Gulf Breeze, Florida 32561, USA
3US Army Engineer Research and Development Center, Mail Stop EP-W, 3909 Halls Ferry Road, Vicksburg, Mississippi 39180, USA
4University of Maryland Center for Environmental Science, Chesapeake Biological Laboratory, PO Box 38, Solomons, Maryland 20688, USA

ABSTRACT: Pomeroy et al. (2006) proposed that temporal and spatial mismatches between eastern oyster filtration and phytoplankton abundance will preclude restored stocks of eastern oysters from reducing the severity of hypoxia in the deep channel of central Chesapeake Bay. We refute this contention by presenting arguments, data, and model results, overlooked by these authors. Our analysis indicates that oyster populations living on extensive reefs along the flanks of the mainstem Bay could substantially reduce summer phytoplankton growth and particulate organic carbon deposition to deep waters of the central channel. Because hypoxia in these deep waters is maintained through microbial decomposition of organic carbon generated by summer phytoplankton production, we conclude that reduced carbon fluxes to the deep channel associated with greatly increased oyster grazing could reduce the severity of hypoxia.

KEY WORDS: Algal blooms · Biodeposition · Crassostrea virginica · Chesapeake Bay · Hypoxia · Oyster · Restoration · Suspension-feeder · Water quality

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