Estuary

Abiotic Factors

Physical Environment: An estuary is rarely deep, never exceeding more than 100ft. Because estuaries do not occur in any particular latitude temperature, precipitation, and sunlight varies greatly. Water flows from inland to the ocean.

Chemical Environment: Estuaries contain brackish water, which is a mix of fresh and salt water. The salinity is never more than in normal ocean water, and decreases the further inland you go. Compounds that reach the ocean by runoff are present in estuaries.

Geologic Features: An estuary is semi-enclosed, with the ocean at one end and a river on the other.

Estuaries are not affected by the seasons.

Biotic Factors

Producers include, algae, phytoplankton, spike grass, cordgrass, sea grass, purple loosestrife, sea lavender, and other aquatic plants.

Consumers include many different birds, fish, crustaceans, bivalves, and microscopic organisms.

Estuaries are very vulnerable to runoff from nearby farms. Many estuaries have experienced great human impact from the widening of the mouth, where the estuary meets the sea, to allow ships to pass through. This causes erosion and higher salinity within the ecosystem.

Invasive species include purple loosestrife, which suppresses native species, and Asian clams, which cover the riverbed and clog pipes.

Policy

The Estuary Protection Act highlighted the values of estuaries and the need to conserve their natural resources. It authorized the Secretary of the Interior, in cooperation with other Federal agencies and the States, to study and inventory estuaries of the United States, including land and water of the Great Lakes, and to determine whether the Federal Government for protection should acquire such areas.

Restore America's Estuaries is a national nonprofit organization established in 1995 as an alliance of eleven