The benthos is the community of organisms that live in or on the bottom of the Bay and its tributaries. Examples of some benthic animals that live in Chesapeake Bay sediments include clams, amphipods, polychaetes, and isopods. Benthic macroinvertebrates are used as biological indicators because they are reliable and sensitive indicators of habitat quality in aquatic environments and they are ecologically important components of the Chesapeake Bay’s food web.