Objectives • Explainwhy an estuary is a very productive ecosystem. • Comparesalt marshes and mangrove swamps. • Describetwo threats to coral reefs. • Describetwo threats to ocean organisms.
Marine Ecosystems • mainly in coastal , open ocean • organisms in coastal areas adapt to changes in water level and salinity. • organisms that live in the open ocean adapt to changes in temperature, amount of sunlight , nutrients available. • http://vimeo.com/14038219
Coastal Wetlands • coastal land areas covered by salt water for all or part of the time • provide habitat, nesting areas for many fish and wildlife • absorb excess rain, filter out pollutants and sediments • provide recreational areas for boating, fishing, hunting
Estuaries • an area where fresh water from rivers mixes with salt water from the ocean • currents form - cause mineral rich mud to fall to the bottom making it available to producers • very productive • constantly receive nutrients from the river and ocean • surrounding land protects from harsh ocean waves
Plants and Animals of Estuaries • support many marine organisms because they receive plenty of light and nutrients • large populations of rooted plants and plankton provide food for fish, which are then eaten by larger animals • oysters and clams live anchored to rocks, feed by filtering plankton
Plants and Animals of Estuaries • organisms able to tolerate variations in salinity because salt content varies as waters mix • provide protected harbors, access to the ocean, and connection to rivers • many ports built on estuaries • six of the ten largest urban areas built on estuaries (New York)
Threats to Estuaries • used as places to dump waste. sewage, pesticides, fertilizers, and toxic chemicals • cannot cope with the amounts produced by dense human populations. • filled-in to be used as building sites.
Salt Marshes • characterized by grasses, sedges, and other plants that have adapted to continual, periodic flooding • primarily found in temperate and subarctic regions • supports a community of clams, fish, aquatic birds, crabs, and shrimp. • absorb pollutants to help protect inland areas
Mangrove Swamps • tropical or subtropical marine swamps with many low to tall mangrove trees. • protect the coastline from erosion, reduce the damage from storms • provide a home for about 2,000 animal species • filled with waste, destroyed in many parts of the world
Rocky and Sandy Shores • Rocky shores - many more plants and animals than sandy shores • rocks provide anchorage for seaweed that animals live on • Sandy shores - dry out when the tide goes out • many organisms live between sand grains, eat plankton left stranded • Barrier island- long ridge of sand or narrow island that lies parallel to the shore, helps protect mainland
Coral Reefs • limestone ridges found in tropical climates • composed of coral fragments that are deposited around organic remains. • thousands of species of plants and animals live in the cracks and crevices of coral reefs • among the most diverse ecosystems on Earth • corals – predators, use stinging tentacles to capture small animals, zooplankton nearby
Coral Reefs • Corals live only in clear, warm salt water where there is enough light for photosynthesis.
Disappearing Coral Reefs • productive ecosystems, but very fragile • water too hot or too cold, or if fresh water enters area - the coral may die • water too muddy, polluted, high in nutrients - the algae within the corals either die or grow out control. • too much algal growth may kill corals
Disappearing Coral Reefs • oil spills, sewage, pesticides, and silt runoff linked to coral-reef destruction. • overfishing can devastate fish populations, upsetting ecosystem. • reefs grow very slowly • may not be able to repair itself after chunks of coral are destroyed by careless divers, ship anchors, people breaking off pieces
Oceans • water absorbs light, usable sunlight penetrates only about 100 m into the ocean • ocean’s life concentrated in shallow coastal waters where sunlight penetrates, rivers wash nutrients from the land. • seaweed and algae grow anchored to rocks, phytoplankton drift on the surface • invertebrates and fish feed on these plants
Plants and Animals of Oceans • In the open ocean, phytoplankton grow only in areas where there is enough light and nutrients • least productive ecosystem • smallest herbivores are zooplankton, • Include jellyfish , tiny shrimp • fish, marine mammals (whales) feed on the plankton
Plants and Animals of Oceans • depths very dark, so most food at the ocean floor consists of dead organisms that fall from the surface • decomposers, filter feeders, and the organisms that eat them live in the deep areas of the ocean.
Threats to the Oceans • runoff from fertilized fields, industrial waste, sewage major sources of pollution • overfishing and certain fishing methods destroy some fish populations. • marine mammals can get caught, drown in fishnets • discarded fishing lines (now illegal) can strangle, kill fish and seals
Arctic and Antarctic Ecosystems • arctic ecosystems at both Poles depend on marine ecosystems because nearly all the food comes from the ocean. • Arctic Ocean - rich in nutrients from the surrounding landmasses • supports large populations of plankton, diversity of fish in the open water and under the ice, ocean birds, whales and seals, polar bears and people on land
Arctic and Antarctic Ecosystems • Antarctic - only continent never colonized by humans. • governed by an international commission, used mainly for research. • even during the summer, only a few plants grow at the edges of the continent. • as in the Arctic, plankton form the basis of the Antarctic food web • birds (Penguins), not mammals on land