Bottom-Dwelling (Benthic) Invertebrates

Science Center Objects

In addition to studying birds and fish, the USGS monitors benthic (bottom dwelling) invertebrate communities (crustaceans, worms, and bivalves, including invasive clams) in the Bay-Delta. 

Benthic invertebrates are an important component in understanding the estuarine ecosystem because they link water and sediment with the aquatic food web for fishes and some waterbirds. Because benthic invertebrates live in bottom sediments, they are subject to changing environmental conditions, including salinity, temperature, sediment, oxygen, nutrients, and contaminants. Some invertebrates have narrow environmental tolerances and are considered reliable indicators for water quality. In some instances, the benthic invertebrates themselves can influence water quality. For example, the invasion of the Asian clam (Potamocorbula amurensis), a very efficient filter feeder, has altered the Bay-Delta system by dramatically reducing phytoplankton (diatoms and other single-celled plants) that form the base of the aquatic food web. Because these invasive clams are efficient filter feeders, they also accumulate sediment-bound contaminants in their tissues, which can harm fish (such as sturgeon (Acipenser)) that eat large numbers of these clams.


For more information see:

San Francisco Bay Benthic Macroinvertebrate Atlas

Trace Metals in San Francisco Bay Clams


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