Chapter 15 Wetlands 365 Copyright Goodheart-Willcox Co., Inc. Coastal Wetlands Coastal wetlands include any coastal area that retains water and drains into a larger body of water, traditionally a sea or an ocean, Figure 15-8. In the United States, coastal wet- lands are wetlands that drain directly into the Atlantic Ocean, Pacifi c Ocean, Gulf of Mexico, and the Great Lakes. Some coastal wetlands extend just a few feet onto the shore, whereas others extend inland for miles. Coastal wetlands are extremely important for migratory bird populations, providing excel- lent food and habitat for a wide variety of species. Coastal wetlands also provide calm locations for fi sh to breed and refuges for amphibian, mam- mal, and reptile species. Coral Reef Wetlands Coral reef wetlands are complex, under- water ecosystems built by generations of stony coral secretions of calcium carbonate. The coral larvae attach to rocks or soil near a coast and become polyps. The polyps excrete the calcium carbonate, which forms their exoskel- eton. The solid coral reef is formed as more and more polyps attach to the substrate. Coral reef wetlands cover only 0.2% of the ocean floor but support more than 25% of all marine species, including sponges, fish, and inver- tebrates, such as slugs, anemones, and sea urchins, Figure 15-9. Coral reef wetlands are found in shallow waters along coastal regions of the ocean or sea. The coral only attach to substrates in areas that are constantly wet. The environment in which a coral reef exists must include the following: • Shallow, clear water which allows sunlight for photosynthesis of various forms of plant life • Warm water temperatures averaging between 73°F and 84°F (23°C and 29°C) coral reefs cannot tolerate water temperatures below 64°F (18°C) or above 104°F (40°C) for any period of time • Specifi c water salinity of 32 psu to 40 psu (practical salinity units) (a psu is a measure of the saltwater’s electrical conductivity) • Water pH of approximately 8.3 Coral reefs are second only to rain forests in biodiversity of species. Did You Know? EcoPrint/Shutterstock.com Figure 15-8. Coastal wetlands in Mozambique provide essential habitat for many species of wildlife. These include fish, crustaceans, amphibians, and birds. Brian Kinney/Shutterstock.com Figure 15-9. The variety of marine life living on a coastal reef is often very colorful and diverse. People often travel to areas where they can snorkel or dive to observe these wetlands.