Grazing impact of the invasive clam Corbula amurensis on the microplankton assemblage of the northern San Francisco Estuary

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 431:183-193 (2011) - DOI: https://doi.org/10.3354/meps09099 Grazing impact of the invasive clam Corbula amurensis on the microplankton assemblage of the northern San Francisco Estuary Valerie E. Greene 1,2,*, Lindsay J. Sullivan1, Janet K. Thompson2, Wim J. Kimmerer1 1Romberg Tiburon Center for Environmental Studies, San Francisco State University, Tiburon, California 94920, USA 2U.S. Geological Survey, Menlo Park, California 94025, USA *Email: vegreene@usgs.gov ABSTRACT: Grazing by the overbite clam Corbula amurensis (formerly known as Potamocorbula) may be the cause of substantial declines in phytoplankton biomass and zooplankton in the San Francisco Estuary (SFE) following its introduction in 1986. While grazing rates have been examined on bacteria, phytoplankton, and copepod nauplii, the consumption of protistan microzooplankton by C. amurensis has not previously been measured. In this study, laboratory feeding experiments revealed that C. amurensis cleared 0.5 l ind–1 h–1 of microzooplankton (ciliates) and 0.2 l ind–1 h–1 of chlorophyll (chl) a. Despite the higher clearance rate on microzooplankton, clams obtained more of their carbon from phytoplankton, which dominated the prey assemblage on most dates. When the measured clearance rates are extrapolated to field populations of clams, fractional loss rates (50 to 90% d–1) exceed the population growth capacity of microzooplankton. Although microzooplankton may not be a major component of the diet of these clams, C. amurensis may further alter food web dynamics through consumption of this important trophic intermediary, thus disrupting this link from bacteria and phytoplankton to higher trophic levels. KEY WORDS: Bivalves · Benthic-pelagic coupling · Microzooplankton · Microphytoplankton · Low-salinity zone · Ciliates Full text in pdf format PreviousNextCite this article as: Greene VE, Sullivan LJ, Thompson JK, Kimmerer WJ (2011) Grazing impact of the invasive clam Corbula amurensis on the microplankton assemblage of the northern San Francisco Estuary. Mar Ecol Prog Ser 431:183-193. https://doi.org/10.3354/meps09099Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 431. Online publication date: June 09, 2011 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2011 Inter-Research.