BIOL 111 Chapter Notes - Chapter 7: Hadal Zone, Littoral Zone, Benthic Zone
5 Feb 2016
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Document Summary
Aquatic life zones: most aquatic life zones can be divided into three layers: surface, middle, and bottom, levels of dissolved o2 are highest near the surface. Levels of co2 are lowest near the surface: photosynthesis is confined to the surface, or the euphotic zone, where sunlight can penetrate, saltwater and freshwater life zones contain four major types of organisms: Benthos (eg, barnacles, oysters, lobsters, crabs), which dwell on the ocean floors. Strongly swimming nekton (consumers), such as fish, turtles, and whales. Weakly swimming, free-floating plankton, carried by currents. Phytoplankton (producers), such as many types of algae. Ultra-plankton, photosynthetic bacteria responsible for 70% of aquatic photosynthesis: saltwater life zones contain about 250,000 known species. The coastal zone is the warm, nutrient-rich, shallow water. Although it makes up 10% of the oceans, it contains 90% of all marine species. Estuaries are partially enclosed areas where seawater mixes with freshwater. Coral reefs form in clear, warm, coastal waters of the tropics and subtropics.
