The Marine Biome Cycle carbon dioxide and oxygen on Earth Modifies temperatures changes Most important: provides stability to the web of life on Earth

The World Ocean World ocean is divided into zones based on depth and distance from the shore Depth zones: photic, aphotic, benthic zones Shore distance zones: oceanic, neritic, intertidal zones

Oceanic Zone This is the open ocean Largest zone in the ocean, 90% of the world ocean Ranges in depth: 500 meters to 11,000 meters deep Not much sunlight penetrates into the oceanic zone Photic zone is only at the surface, about 200 m deep Only phytoplankton are the producers They convert CO2 into billions of tons of carbon each year This provides the basic material for the bottom of the food web Plankton is the food source for both large and small ocean animals: fish and whales

Aphotic zone-takes up most of the world ocean, but does not have much organism diversity Limited by absence of sunlight Organisms have to adapt to cold, dark, deep water Feed on pieces of dead organic material that sinks down from surface Detritus-tiny pieces of dead organic material that are food for organisms at the base of an aquatic food web Clams, worms, sponges all feed on detritus

Neritic Zones Neritic zone- the ocean region b/n the edge of the continental shelf (500 m below Sea level) and the low tidemark It’s usually shallow, so gets sunlight for photosynthesis, therefore most productive Only 10% of the ocean Neritic zones include reefs and estuaries

Coral Reefs Reef- natural structure built on a continental shelf Coral reefs found in warm, tropical waters Kelp reefs found in cold waters Importance of coral reefs: Home to huge variety of organisms Breeding and feeding place for many fish 1/3 of all ocean fish live on or depend on coral reefs Protects shoreline from erosion Many coral reef organisms have medical benefits

Coral reefs are very fragile Made of calcium carbonate skeletons of millions of tiny corals Top layer is alive Zooxanthellae alga lives inside tissue of coral Alga perform photosynthesis and provide food to coral Human Damage of coral reefs Blast reefs to make harbors Coral is harvested for jewelry Fish are popular for home aquariums Collecting the fish damages the coral

Water pollution damage Toxic chemicals kill coral and organisms Silt, sand, and topsoil wash into the water and make it cloudy, less light for photosynthesis So can look at health of coral reef to determine the quality of water When coral reefs start to die, start to investigate the water quality Estuaries Region where a freshwater source, usually mouth of a river, meets the saltwater of the ocean Water is usually brackish here

Nutrients and sediments are mixed here Many marine organisms breed here, commercially important Function as buffer zone, filter sediments and pollutants from the water Slow down floods and storm water Humans use for boating, fishing, hunting Neritic Zone Production Sunlight can reach it, so photosynthesis occurs Many mineral nutrients wash into the zone from the shore Tides wash in fresh nutrients and O2, and takes away waste

Fringe reefs-grows just off shoreline The reef will keep growing farther out The reef closest to the shore will start to die, creating a channel Forms a barrier reef- reefs that are separated from the shore by a channel Great Barrier Reef in Australia is largest coral reef in world

Intertidal Zones This zone located along the shoreline Alternates twice a day b/n periods of exposure at low tide and periods of submersion at high tide 2 high tides and 2 low tides each day Any organisms living there must be able to withstand these constant changes, and pounding of water Attach to rocks, burrow in sand Often surrounded wetlands: salt marshes and mangrove swamps

Salt Marshes Flat, muddy wetlands surround estuaries, bays, and lagoons Mud floor is exposed during low tides, and submerged during high tides Common in US coasts, especially east coast Functions Support migratory bird populations: feeding and resting grounds in b/n journeys Plant life (grasses) support rich community of fish and invertebrates Many shellfish and fish spend part of their life there, so they can be easily captured for sale Plants are their food and protection

Salt Marsh Formation Streams flow into an estuary or shallow, neritic water Sediments are deposited at the mouth of the stream, and build up forming a delta the delta begins to sink. Subsidence-the weight of accumulated sediments cause the delta to sink under the water The amount that sinks has to balance the amount that is deposited for a salt marsh to remain This sinking and depositing of sediments causes the river to change its course many times

Mangrove Swamps Coastal wetland that occurs only in warm climates Named after the mangrove plant that lives there Mangroves cannot grow in areas that freeze more than 2 days a year Mangroves can either be a tree or shrub, 800 species total, 10 live in US Most common in US is red mangrove Adaptations Low O2 in swamps Mangroves have roots that grow up and stick out of the water Some have roots that grow high on the trunk, look like stilts

Mangrove swamps are being destroyed at a high rates Make great commercial fish and shrimp ponds Construction projects Waste dumping