Oysters are an important component of the living ecosystem of the Chesapeake Bay and its tributaries. They are important on both an ecological and an economical level.
The most widely known ecological function of the oyster is that they filter the water. Oysters are considered the vacuum cleaners of the Chesapeake Bay. They filter the water removing organic and inorganic particles from the water column resulting in cleaner water which positively impacts other species. Oysters can selectively choose and feed on microscopic phytoplankton, or algae, removing the algal biomass from the water. Oysters also remove other suspended solids from the water column and package them into bundles which they release as pseudofeces. This bundle is then utilized by other organisms on the oyster reef for food.
The presence of oyster shells creates a hard bottom substrate that provides habitat for other bay organisms. Many critters depend on the existence of the shell to grow. Barnacles, mussels, and anemones all require a hard bottom on which to attach and to grow. Oyster reefs also provide shelter and spawning areas for the Bay residents. Oyster gobies and blennies use dead oyster shells, or boxes in which to lay their eggs. The gaping oyster shell provides a substrate for the eggs to be attached to, while offering protection from predators at the same time. The nooks and crannies of the reef formation offer habitat to different species of worms, mollusks, fish, and mud crabs. The presence of these organisms attracts larger predators which in turn attracts even larger predators. The existence of an oyster reef truly creates a dynamic environment.
Oysters are also important on an economic level since they provide a market for food and a way of life for many watermen of the Chesapeake Bay. Oysters are considered a keystone organism. Without the presence of the oyster reef other critters would not be able to move in and colonize the reef. Oysters filter the water, provide habitat, and reproduce to increase natural numbers in the Bay.