The Marine Biome

•Cycle carbon dioxide and oxygen on Earth•Modifies temperatures changes•Home to many organisms•Most important: provides stability to the web of life on Earth

The World Ocean• Even though we name individual oceans,

they are all connected so they make up one large body of water-the world ocean

• it is one large biome with many ecosystems and habitats

• 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

Ocean Water• Even though all ocean water is connected, it is

not all the same• Differ in temperature, salinity, and density• Water near the equator gets more direct

sunlight so it is warmer and more saline and (water evaporates b/c of the sunlight)

• Water near the poles is colder, and less saline, and more dense

• It is constantly getting more water from melting glaciers and ice caps

Ocean Currents• Ocean water flows in similar patterns all year, called currents• Currents are driven mostly by winds• They are pretty stable and remain the same even though

there are small changes• Currents can cause water located very close together to be

very different• Currents allow fish and organisms to travel quickly over long

distances• Currents have kept pollutants dumped by people

concentrated in areas• Fish become polluted and humans eat the fish• Ocean Dumping Act(1988) banned dumping industrial waste

in the ocean

Neritic Zones•Continental shelf- the shallow border that surrounds the continents •Runs b/n the shore and 500 m below the surface of the water•Neritic zone- the ocean region b/n the edge of the continental shelf and the low tidemark•It’s usually shallow, so gets sunlight for photosynthesis•Only 10% of the ocean•But are the most productive b/c they get sunlight and are warm•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

LOW TIDE

HIGH TIDE

• 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

Review Questions1. What is the most important thing that the marine biome

provides for the Earth?2. What is the name given to all of the oceans connected

together?3. What are the names of the 3 zones based on shore distance?4. What is the largest zone, and how much space does it take up?5. What is detritus? Why is it important?6. Where is ocean water the warmest? Coldest?7. What are ocean currents?8. How do ocean currents contribute to polluting the ocean?9. What is the neritic zone and how much space does it take up?10. Why are coral reefs important?