Chapter 3 Communities and Biomes Section 2, Part 1 Aquatic Biomes

Biomes A large group of ecosystems that share the same type of climax community.

Aquatic Biomes Approx. 75% of Earth is covered by water. 3 Main Aquatic Biomes Marine Biomes Estuaries – Mixed Waters Freshwater Biomes

Marine Biomes – Open Oceans Differ in abiotic factors, such as: Salinity, depth, light, and temperature Large amounts of biomass. Mostly extremely small to microscopic organisms, which larger organisms depend on. Plankton Small organisms that drift and float. Include autotrophs, diatoms, eggs, and juvenile stages of marine animals. Serve as the base of all aquatic food chains.

Zones Photic Zone Shallow enough for sunlight to penetrate. Exist along coastlines. Include bays, rocky shores, sandy beaches, mud flats, estuaries, and coral reefs.

Zones Aphotic Zone Deeper water that never receives sunlight.

Estuaries Coastal body of water, partially surrounded by land, in which freshwater and saltwater mix. Salinity changes with the tides and the amount of freshwater brought in by rivers. Because of salinity changes, a wide range of organisms can live in estuaries.

Salt Marsh Ecosystems Dominated by salt-tolerant smooth cordgrass, salt marsh hay, or eelgrasses. Grasses grow so thick that their stems and roots form a tangled mat that traps food and provides a “nursery” habitat for small developing snails, crabs, and shrimp. These organisms feed on suspended decaying material. Attract predators, such as birds.

Intertidal Zones The portion of the shoreline that lies between the high and low tide lines. Size of the zone depends upon the slope of the land and the difference between high and low tides. Intertidal ecosystems have high levels of sunlight, nutrients, and oxygen.

Intertidal Zones Differs in rockiness and wave action. Rocky Sandy Waves constantly threaten to wash organisms into deeper waters. Organisms such as snails and sea stars have adaptations that act by suction to hold onto rocks. Barnacles secrete a strong glue which helps them stay anchored. Sandy Clams, worms, snails, and crabs survive by burrowing in the sand.

Tide Pools Pools of water left when the water is a t low tide. Can isolate organisms that live in the intertidal zone until the next high tide. Can vary in nutrient and oxygen levels from one time of day to another.

Marine Biomes As you move into deeper water, the ocean bottom is less affected by waves and tides. Nutrients washed from land by rainfall and runoff contribute to the abundant life and high productivity.

Coral Reefs One of the most diverse ecosystems. Formed over long periods of time from the calcium carbonate shells secreted by corals. Very fragile ecosystem.

Freshwater Biomes Rivers and Streams Quicker flowing streams and rivers have higher oxygen content. Higher nutrients and plant life exist in slower moving parts.

Lakes and Ponds Organisms Temperature Sunlight Cattails, tadpoles, aquatic insects, turtles, worms, crayfish, insect larvae, whirligig beetles, dragonflies, and fish. Temperature Decreases with depth. Sunlight

Wetlands Marshes and Swamps Bogs Found inland and in coastal regions. Highly productive and are the source of food for many migratory birds. Have flowing water. Swamps have trees. Marshes do not. Bogs Get their water supply form rain. No flowing water.