Cracking the AP Environmental Science Exam, 2020 Edition by The Princeton Review

Author:The Princeton Review
Language: eng
Format: epub
Publisher: Random House Children's Books
Published: 2020-02-10T16:00:00+00:00

Two Endangered Aquatic Ecosystems

As we’ve reviewed in earlier chapters, coral reefs are structures found in warm, shallow tropical waters that represent diverse and ecologically crucial ecosystems. Coral reefs are created by small marine animals (called cnidarians), which are involved in mutualistic relationships with photosynthetic algae called zooxanthellae. Reefs provide local populations with a great variety of seafood and are popular recreational areas for humans.

In many areas of the world, exploitation has led to severe and irreversible damages to these reefs. One example of such irreversible coral damage is coral bleaching. In coral bleaching, higher-than-usual water temperatures cause the death of the zooxanthellae, and this in turn causes the death of the coral reef. While some bleaching is normal, high water temperatures can be caused by weather fluctuations such as El Niño, and since this is a periodic event, coral bleaching is an ongoing concern.

Another threatened aquatic ecosystem is the mangrove swamp. Mangrove swamps are coastal wetlands (areas of land covered in fresh water, salt water, or a combination of both) found in tropical and subtropical regions, and they are threatened by activities such as shrimp aquaculture and the degradation of the Western coastlines. Mangroves are characterized by trees, shrubs, and other plants that can grow in brackish tidal waters and are often located in estuaries, which as you learned earlier are areas where freshwater meets salt water. In North America, mangrove swamps are found from the southern tip of Florida along the entire Gulf Coast to Texas; Florida’s southwest coast supports one of the largest mangrove swamps in the world.

A huge diversity of animals is found in mangrove swamps. Because these estuarine swamps are constantly replenished with nutrients transported by freshwater runoff from the land, they support a bursting population of bacteria, other decomposers, and filter feeders. These ecosystems also sustain billions of worms, protozoa, barnacles, oysters, and other invertebrates, which in turn feed fish and shrimp, which support wading birds, pelicans, and, in the United States, the endangered crocodile.

The importance of mangrove swamps has been well established. They function as nurseries for shrimp and recreational fisheries, exporters of organic matter to adjacent coastal food chains, and enormous sources of nutrients valuable to plants, wildlife, and ecosystem function. Their physical stability also helps to prevent shoreline erosion, shielding inland areas from severe damage during hurricanes and tidal waves.

Along with the Whaling Commission, there are many laws and regulations pertaining to preserving ocean resources. A few that the College Board is likely to ask about are the following:

Date

Name of Legislation

What It Did

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