Ocean surface temperatures vary with amount of solar radiation

Amount of solar radiation depends greatly on latitude and depth.

Ocean temperature variation

Thermoclines are not present at high latitudes

The water column is isothermal (iso=same, thermo=heat)

Thermocline: the layer of the ocean where there is a rapid decline of temperature (thermo= heat, cline=slope)

Density is the mass per unit volume of a substance

Ocean density variation

Density= mass/volume

D=m/v

Salt water is more dense than freshwater.

Factors that affect seawater density:

• Salinity

• Temperature

Pycnocline: the layer of ocean water where there is a rapid change of density with depth. pycno= densitycline= slope

Pycnoclines are not present at high latitudes

Density is inversely proportional to temperature.

As temperature increases, density decreases

As temperature decreases, density increases

Oceanographers recognize a three-layered structure in most parts of the ocean

• Mixed zone (2%)

• Transitional zone (18%))

• Deep zone (80%)

The Ocean Zones