11-2 Neritic 11-2 Neritic ZonesZones• Where the edges of the continents meet the Where the edges of the continents meet the

oceans.oceans.• The water is relatively shallow here.The water is relatively shallow here.• The The continental shelfcontinental shelf is the shallow border is the shallow border

that surrounds the continent. It extends that surrounds the continent. It extends about 500m below the surface of the water.about 500m below the surface of the water.

• The neritic zone is the ocean region between The neritic zone is the ocean region between the edge of the continental shelf and the low the edge of the continental shelf and the low tidemark. These waters are in the photic tidemark. These waters are in the photic zone so photosynthesis occurs. They account zone so photosynthesis occurs. They account for about 8% of the total ocean waters. for about 8% of the total ocean waters. These waters are the most productive parts These waters are the most productive parts of the oceans.of the oceans.

Continental Continental ShelfShelf

2 Types of Neritic 2 Types of Neritic EcosystemsEcosystems

•ReefsReefs

•EstuariesEstuaries

ReefsReefs•A natural structure built on a A natural structure built on a

continental shelf.continental shelf.

•Coral reefsCoral reefs are found in warm are found in warm tropical waters.tropical waters.

•Kelp reefsKelp reefs (kelp beds) are found (kelp beds) are found in colder waters.in colder waters.

•Barrier reefsBarrier reefs are reefs in areas are reefs in areas of reduced oxygen and nutrients.of reduced oxygen and nutrients.

Coral ReefsCoral Reefs• The rain forests of The rain forests of

the marine biome.the marine biome.• Very productive Very productive

ecosystems.ecosystems.• Home to huge Home to huge

variety of variety of organisms.organisms.

• ( 1 main ( 1 main importance) importance) breeding and breeding and feeding grounds feeding grounds of many types of of many types of fish.fish.

• 1/3 of all fish in the 1/3 of all fish in the ocean live on or ocean live on or depend on the coral depend on the coral reef.reef.

• (Another importance) (Another importance) protects shoreline from protects shoreline from erosion.erosion.

• (Another importance) (Another importance) many coral reef many coral reef organisms have organisms have medicinal value.medicinal value.

• Made up of calcium Made up of calcium carbonate skeletons of carbonate skeletons of millions of coral millions of coral animals.animals.

Coral ReefsCoral Reefs• Only top layer is Only top layer is

alive.alive.

• Depend on symbiotic Depend on symbiotic relation with alga relation with alga called called zooxanthelle.zooxanthelle.

• This alga carries out This alga carries out photosynthesis and photosynthesis and provides food for the provides food for the coral reef.coral reef.

Human Impact on Coral Human Impact on Coral ReefsReefs• Blasted to make Blasted to make

harbors and harbors and shipping channels.shipping channels.

• Coral is harvested Coral is harvested and sold as jewelry.and sold as jewelry.

• When colorful fish When colorful fish are collected for are collected for home aquariums, home aquariums, the coral reef the coral reef (where these fish (where these fish are found) is are found) is damaged.damaged.

• Water pollution is Water pollution is also a damaging also a damaging cause.cause.

• When coral reefs When coral reefs are affected by are affected by chemicals, they chemicals, they show rapid death. show rapid death. This is one reason This is one reason why coral reefs are why coral reefs are a good indicator of a good indicator of pollutions.pollutions.

Estuaries Estuaries • A region where a A region where a

freshwater source, freshwater source, usually the mouth usually the mouth of a river, meets of a river, meets the saltwater of the the saltwater of the ocean.ocean.

• Subject to the rise Subject to the rise and fall of the tides.and fall of the tides.

• Water is brackish.Water is brackish.• Used as spawning Used as spawning

grounds for many grounds for many organisms. organisms.

• Humans use Humans use estuaries for estuaries for boating, hunting and boating, hunting and fishing.fishing.

• Estuaries act as Estuaries act as buffer zones, buffer zones, filtering sediments filtering sediments and pollutants from and pollutants from the water.the water.

• They also ease the They also ease the effects of storms and effects of storms and floods by slowing the floods by slowing the flow of water. flow of water.

EstuariesEstuaries

Neritic Zone Neritic Zone ProductivityProductivity

•Since the water is shallow, Since the water is shallow, the sunlight reaches the the sunlight reaches the benthic community.benthic community.

•Photosynthesis takes place Photosynthesis takes place in all zones.in all zones.

•Water is high in minerals.Water is high in minerals.