Estuaries What is an estuary An estuary is

Estuaries

What is an estuary? An estuary is a semi-enclosed coastal body of water connected to the ocean with a measurably different salinity. Estuaries are classified by… Geology: this describes how the estuaries are formed. The geographical features separate fresh from salt water. Water Circulation: this describes how the water in the estuaries mixes. The river’s flow and the ocean’s tides control the mixing.

What is salinity? Salinity is defined as all of the dissolved minerals in water. Most of these are types of salt. Most of the “salts” in salt water come from minerals on the land that are chemically weathered (dissolved) by groundwater. We measure salinity in parts per thousand = 0/00 The ocean’s average salinity is 35 0/00 or 3. 5 0/0

Classification by Geology

Coastal Plain Periodically flooded low-lying flat areas.

Bar-Built Created through the deposition of sediment along a coastline.

Tectonic Created when tectonic forces reshape the landscape.

Deltas Created by the deposition of sediment at the mouth of a river.

A North Carolina Estuary Food Web

Why We Need Estuaries Movie Estuaries act as sponges that absorbs storm surge and filter pollutants from water before it drains into the ocean.

Productivity: when autotrophs make carbohydrates. In estuaries, the mixing of nutrients from freshwater and seawater, along with plentiful sunlight, makes these areas some of the best places for photosynthesis on the planet.

Estuaries as Nurseries Movie Because estuaries have lots of producers and are protected from waves, they make good nurseries for young sea creatures. Many important commercial fishes and shellfishes spend at least a portion of their life cycle in the protected waters of an estuary.