Hobbies And Interests
Definition of an Estuary
The combination of the waters that comprise estuaries is commonly referred to as brackish. Due to this combination, the flora and fauna that develop are rare. They must develop adequate adaptations in order to survive in salinated water. Not only are the ecosystems of estuaries unique, they're also the most productive, according to the the National Oceanic and Atmospheric Administration. Shelter, food and reproduction are provided by estuaries for many of their inhabitants. People also work, hunt and play near estuaries.
Effect on Sea Level
The primary threat to estuaries caused by global warming is an increase in the sea level. According to the Environmental Protection Agency, the sea level rises for three reasons: expansion of warming water, melting glaciers and ice caps, and human activity. Furthermore sea level does not increase equally in all areas, instead varying based on the level of subsidence, which is the downward movement of the earth relative to sea level. One side effect of an increase in sea level is saltwater intrusion. Salt enters coastal freshwater and may convert the body of water into a salt marsh.
Effect on Organisms
Estuarine-dependent species are affected by global warming as it interacts with their environment. The rise in sea level caused by global warming can have opposite effects on nursery habitats. Along the Atlantic coast, southern areas are spared and actually experience growth in their nursery habitats due to spawning atop the continental shelf. However, in northern areas, spawning occurs in more secure bays, susceptible to flooding. Shrimp are also affected by changes in sea level in the northern Gulf of Mexico. As the sea level rises and the estuary decreases, it breaks up the habitat of the shrimp, but this then raises shrimp production due to increased access to the estuary. However if the sea level keeps rising, it will eventually reduce shrimp production.
Other Effects
Global warming has a host of other various effects on estuaries, including increased air surface and sea temperatures, as well as changes in rainfall and wave circulation patterns. Increased air temperatures cause greater stratification in coastal lakes, a reduction in estuary runoff due to evaporation, and an increased risk of fire in vegetation around estuaries. The volume of rainfall into an estuary may be reduced, but fall in normal patterns, or remain the same and fall fewer times. Global warming could furthermore impact the formation of estuaries by altering the wave patterns that deposit essential sediment.