Chapter 8 aquatic life zones The aquatic equivalents of biomes are called aquatic life zones. benthos The third type, benthos, consists of bottom dwellers such as oysters, which anchor themselves to one spot; clams and worms, which burrow into the sand or mud; and lobsters and crabs, which walk about on the sea floor. coastal wetlands coastal land areas covered with water all or part of the year coastal zone the warm, nutrient-rich, shallow water that extends from the high-tide mark on land to the gently sloping, shallow edge of the?continental shelf. coral reefs form in clear, warm coastal waters of the tropics and subtropics. cultural eutrophication