Ocean Zones and Currents

Mixed Layer Zone

Depth: 0-250 meters below sea level; Temperature: Average of 22°C; Notes: Most amount of sunlight and contains phytoplankton.

Thermocline Zone

Depth: 250 to 1000 meters below sea level; Temperature: Drops significantly 22°C-6°C; Notes: Sunlight starts to disappear and temperatures drop.

Deep Water Zone

Depth: 1000 meters and deeper; Temperature: Consistently cold 6°C-2°C; Notes: No sunlight.

Continental Slope

Edge of the continent. Upwelling happens here.

Seamounts

Volcanic mountains that haven't reached the water's surface.

Abyssal Plain

Flat deep ocean floor.

Mid Ocean Ridge

Volcanic mountain system formed at divergent boundaries.

Volcanic Islands

Volcanic mountains above the surface, surrounded by water formed at Convergent Subduction boundaries and at Hot Spots.

Continental Shelf

The part of the continent submerged underwater.

Trench

A deep sea depression formed from a convergent subduction boundary.

Seafloor Spreading

Tectonic plates pull apart at Divergent plate boundaries. Magma rises to create a new ocean floor.

Salinity

The salt concentration in the ocean ranges from 33-37 ppt (parts per thousand).

Surface currents

Driven mainly by wind. Warm currents travel from the equator to the poles. Cold currents travel from the poles to the equator.

Deep Ocean Currents

Driven by density differences. Cold, salty water has a higher density - sink in the ocean.

Thermohaline Circulation

The connection between surface and deep ocean currents.

Upwelling

Deep ocean currents move up to the surface bringing very cold, nutrient-rich water to the surface.

El Nino

A cyclical current occurring every two to seven years in the Pacific Ocean that disturbs global weather patterns.

La Nina

The opposite of El Nino; allows upwelling to occur off the coast of South America.

Specific heat capacity

An object's ability to absorb and retain heat.

Sea Breeze

The land is warmer than the water; winds blow from high pressure to low pressure so air moves from the ocean to land.

Land Breeze

The land is cooler than the water; winds blow from high to low, so the air moves from the land to the ocean.