Chapter 6 Review Questions
1. Coral reefs are elaborate networks of crevices, ledges, and holes made up of calcium carbonate; coral polyps are tiny animals that build coral reefs by secreting a crust of limestone around their bodies that accumulate once multiple polyps die. Coral reefs help moderate atmospheric temperatures by removing CO2 from the atmosphere, act as natural barriers that help protect 15% of the world’s coastlines from erosion by battering waves and storms, provide habitats for a variety of marine organisms, produce about one-tenth of the global fish catch, one-fourth of the catch in developing countries, provide jobs and building materials for some of the world’s poorest countries, and support fishing and tourism industries worth billions of dollars each year. Coral bleaching is when a coral becomes stressed and the algae on which it depends for food and color die out, leaving an underlying white or bleached skeleton of calcium carbonate; this occurs because of increased water temperatures and runoff of silt from the land.
2. The two major aquatic life zones are saltwater (marine) and freshwater life zones.
3. Phytoplankton (plank plankton) are multiple types of algae; Zooplankton (animal plankton) are primary and secondary consumers which feed off phytoplankton (primary consumers) or other zooplankton (secondary consumers); these range from protozoa to large invertebrates such as jellyfish. Ultraplankton are much smaller plankton that may be responsible for 70% of the primary productivity near the ocean surface. Nektons are strongly swimming consumers such as fish, turtles, and whales. Benthoses are bottom dwellers that attach themselves to one spot (e.g. barnacles, oysters, worms, lobsters, crabs). Decomposers are organisms (mainly bacteria) which break down the organic compounds in the dead bodies and wastes of aquatic organisms into simple nutrient compounds for use by aquatic producers.
4. A major advantage of living in an...
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