Properties of Ocean Water

Ch. 20.1 Part 2

Temperature of Ocean Water

Like salinity ocean temperature varies depending on depth and location

Surface Water

The ocean absorbs infrared wavelengths of the that heat the surface of the oceanThe surface water mixes with the water below it, keeping the temperature relatively the same to a depth of 100m to 300mThe total amount of solar energy that reaches the surface is much greater at the equator= warmer tropical water

The polar regions are colder and covered with “pack ice”

Pack Ice- floating layer of sea ice usually no more than 5 m thick.

Insulates water below it and keeps it from freezing

Thermoclines

Zone of rapid temperature drop

Basically, the sun cannot directly heat the ocean water below the surface layer --causing a sharp decrease in water temperature

Thermoclines exist because warm water near the surface is less dense

The warm water sits on top and does not mix with the cooler water below

Deep Water Temperatures

Deep zones below 400m is usually near 2CThe colder the water = more dense water holding more dissolved gases

Density of Ocean Water

Density- the ratio of the mass of a substance to the volume of the substance (g/cm3) Density of pure water = 1 g/cm3

Factors Affecting Density

1. Salinity The large amount of dissolved

solids make ocean water denser than pure water

Density range= 1.026 g/cm3 to 1.028 g/cm3

2. Temperature Ocean water becomes denser as

it becomes colder Temperature affects density more

than salinity

Therefore colder regions are the most dense

Color of Ocean Water

Color of ocean water is determined by the way it absorbs or reflects sunlight Most colors are absorbed= only

blue is reflected

Why is Color Important?

Phytoplankton –small marine plants that provide food for many ocean species Only absorb red and blue—

reflect green Scientist study color to find

phytoplankton