Life at the Ocean’s Edge

Essential Questions What factors affect where ocean organisms live? What factors affect where ocean organisms live? What conditions must organisms in the rocky intertidal zone overcome? What conditions must organisms in the rocky intertidal zone overcome? What are the major types of coastal wetlands? What are the major types of coastal wetlands?

Living Conditions Some physical factors that determine where marine organisms can live include salinity, water temperature, light, dissolved gases, nutrients, and wave action. Some physical factors that determine where marine organisms can live include salinity, water temperature, light, dissolved gases, nutrients, and wave action. The ocean is inhabited by organisms at every depth. The ocean is inhabited by organisms at every depth.

Scientist classify marine organisms according to where they live and how they move. Scientist classify marine organisms according to where they live and how they move. Plankton- tiny algae and animals that float in the water and are carried by waves and currents. Ex: diatoms Plankton- tiny algae and animals that float in the water and are carried by waves and currents. Ex: diatoms Nekton- free swimming animals that can move throughout the water column. Nekton- free swimming animals that can move throughout the water column. Benthos- organisms that inhabit the ocean floor. Ex: crabs, sea stars, lobsters that move from place to place and sponges and sea anemones that remain in one place. Benthos- organisms that inhabit the ocean floor. Ex: crabs, sea stars, lobsters that move from place to place and sponges and sea anemones that remain in one place.

Many plankton are considered producers, while other plankton, benthos, as well as all nekton are consumers. Some of the benthos organisms are decomposers. Many plankton are considered producers, while other plankton, benthos, as well as all nekton are consumers. Some of the benthos organisms are decomposers. These feeding relationships in a habitat make up a food web. These feeding relationships in a habitat make up a food web.

Rocky shores Intertidal zone- stretches from the highest high- tide line on land out to the point on the continental shelf exposed by the lowest low tide line. Intertidal zone- stretches from the highest high- tide line on land out to the point on the continental shelf exposed by the lowest low tide line. Organisms that live in the rocky intertidal zone must be able to tolerate the pounding of the waves and changes in salinity and temperature. They must also withstand periods of being underwater and periods of being exposed to the air. Organisms that live in the rocky intertidal zone must be able to tolerate the pounding of the waves and changes in salinity and temperature. They must also withstand periods of being underwater and periods of being exposed to the air.

Along the Rocks The constantly changing water level in the intertidal zone creates different habitats along a rocky coast. The constantly changing water level in the intertidal zone creates different habitats along a rocky coast. In Tide Pools: When the tide goes out, some water remains in depressions among the rocks called tide pools. When the tide goes out, some water remains in depressions among the rocks called tide pools.

Where River Meets Ocean Estuaries-coastal inlets or bays where fresh water from rivers mixes with the salty ocean water. Estuaries-coastal inlets or bays where fresh water from rivers mixes with the salty ocean water. Water that is partly salty and partly fresh is said to be brackish. Water that is partly salty and partly fresh is said to be brackish. Along the U.S. coasts, most coastal wetlands are either salt marshes or mangrove forest. Along the U.S. coasts, most coastal wetlands are either salt marshes or mangrove forest.

Salt Marshes: Salt water flows through tidal channels in a salt marsh. Salt water flows through tidal channels in a salt marsh. Cordgrass dominates the marsh. It can survive in salt water. Cordgrass dominates the marsh. It can survive in salt water. Organisms in the marsh are protected from the surf. Organisms in the marsh are protected from the surf. Mangrove Forest: Short gnarled trees that grow well in brackish water. They are found along the coastline of Florida. Short gnarled trees that grow well in brackish water. They are found along the coastline of Florida.

Mangroves can withstand all but the strongest hurricane winds and protect the coastline. Mangroves can withstand all but the strongest hurricane winds and protect the coastline. They create a protected nursery rich in nutrients for many young animals. They create a protected nursery rich in nutrients for many young animals. Protecting Estuaries: Rivers that flow into estuaries can carry harmful substances as well as nutrients. Rivers that flow into estuaries can carry harmful substances as well as nutrients. Ocean tides flush the pollutants out of the estuaries, but it can take many years. Ocean tides flush the pollutants out of the estuaries, but it can take many years.

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