Question

Which of the following best describes an estuary?

• A. A fully enclosed freshwater lake
• B. A semi-enclosed coastal ocean area with a free connection to the sea
• C. A deep ocean trench
• D. A large river delta

Answer 1

Answer:

B. A semi-enclosed coastal ocean area with a free connection to the sea

• Many rivers develop a highly specialised zone before joining the proper sea. This zone is called - Estuary

• An estuary is a transitional zone between rivers and sea representing an ecotone possessing unique ecological features and biotic communities.

• An estuary is semi-enclosed part of the coastal ocean containing brackish water that has free connection with the sea on one side and on the other side it is connected with a river mouth and receives fresh water.

• Estuarine sedimons are, anoxic below the first few centimeters unless they have large particle size and/or large number of burrowing animals such as ghost shrimp (Callianassa) and the hemi chordat worm (Balanoglossus)