world’s oceans cover 71% of the earth’s surface oceans

World’s oceans cover 71% of the Earth’s surface

OCEANS

Salt content and water temperature affect water density

WATER DENSITY

More dense (heavier) – colder and saltier

Less dense (lighter) – warmer and less salty

WATER DENSITY

Currents driven by heating and cooling, gravity, and water density

CURRENTS

Great Ocean Conveyor

Upwelling – vertical flow of cold, nutrient-rich water toward the surface

UPWELLING & DOWNWELLING

Horizontal currents diverge

Downwelling – surface waters sink

UPWELLING & DOWNWELLING

Surface currents converge

Warm water pushed down

3 zones photic, aphotic, and benthic

3 zones of the photic zoneIntertidal NeriticOpen ocean

OCEAN STRUCTURE

Intertidal zone High tide line to the lowest low tide line

Intertidal organisms have to be able to withstand being submerged in water, beat by waves, being exposed to the air and sun

3 PHOTIC ZONES

INTERTIDAL ORGANISMS

Intertidal zone (cont’d)Nutrient richLarge number of organisms some burrow into the sand until high tide returns

3 PHOTIC ZONES

Neritic ecosystemExtends from low tide mark to the edge of the continental shelf

SunlitMost productive ecosystems

Kelp forests Coral reefs

3 PHOTIC ZONES

NERITIC ECOSYTEMS

Kelp forestSupplies shelter and food for invertebrates

Invertebrates provide food for predators

Absorbs wave energy and protects shores from erosion

NERITIC ZONE

Coral ReefsShallow tropical & subtropicalTiny invertebrates Get nourishment from symbiotic algae

Corals die and leave behind their calcium carbonate skeleton

Protect shorelines

NERITIC ZONES

Begins at the edge of the continental shelf

Least productive ecosystem!

OPEN OCEAN

Limited photosynthesis occursPhytoplankton are typically the base of food chains in the open ocean

Eaten by zooplanktonEaten by fish, jellyfish, whales, etcThese can be become food for predators

OPEN OCEAN

Animals have many adaptations that allow them to live in the dark and cold parts of the ocean

OPEN OCEAN

Rely on hydrothermal ventsBacteria use the energy from the heated water that flows from the vents

Many species feed on the bacteria and the food chain can continue

BENTHIC ECOSYSTEMS

HYDRO-THERMALVENTS

ventstubeworms