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

Marine Ecology Progress Series

Valerie E. Greene¹  Janet K. Thompson¹  Lindsay J. Sullivan¹  Wim J. Kimmerer¹ 

关键词: Bivalves;    Benthic-pelagic coupling;    Microzooplankton;    Microphytoplankton;    Low-salinity zone;    Ciliates;   

DOI  :  10.3354/meps09099

学科分类：海洋学与技术

来源: Inter-Research

【 摘 要 】

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.

【 授权许可】

Unknown