AP BIOLOGY

Detailed explanation-1: -An estuary is an area where a freshwater river or stream meets the ocean. In estuaries, the salty ocean mixes with a freshwater river, resulting in brackish water. Brackish water is somewhat salty, but not as salty as the ocean.

Detailed explanation-2: -Estuaries and their surrounding wetlands are bodies of water usually found where rivers meet the sea. Estuaries are home to unique plant and animal communities that have adapted to brackish water-a mixture of fresh water draining from the land and salty seawater.

Detailed explanation-3: -Some common estuarine habitats are oyster reefs, kelp forests, rocky and soft shorelines, submerged aquatic vegetation, coastal marshes, mangroves, deepwater swamps, and riparian forests.

Detailed explanation-4: -In a typical estuary, there is a constant change in the salinity of the water. As the tide rises, water from the ocean begins to surge into the mouth of a river, bringing with it higher levels of salt. This results in an increase in the salinity of the water in an estuary.

Detailed explanation-5: -As fresh water is less dense than saltwater, it floats above the seawater. A sharp boundary is created between the water masses, with fresh water floating on top and a wedge of saltwater on the bottom. Some mixing does occur at the boundary between the two water masses, but it is generally slight.