Properties of Ocean Water

Dissolved Gases

• Gases can enter the ocean from streams,

volcanoes, organisms, and the atmosphere.

• Gases dissolve better in colder water

The Oceans as a Carbon Sink

• Large amount of CO2

• Oceans contain more than 60 times as much carbon as the atmosphere does.

Dissolved Solids

• Oceans are 96.5% pure water and 3.5% dissolved solids

• Sea salts

• Halite - Sodium and chloride 85% of solids

Sources of Dissolved Solids

• volcanic eruptions

• weathering of rock on land

• chemical reactions between sea water and newly formed sea-floor rocks

Salinity

• a measure of the amount of dissolved salts in a given amount of liquid

• Ocean 3.5% salts, fresh water 0.1% salts

Factors that Change Salinity

• Evaporation rate, inflow of fresh water

– Salinity higher in tropics

Temperature of Ocean Water

• Surface water depends on amount of solar energy; temp. decreases as latitude increases

• Movement of water (currents)

The Thermocline

• a layer in which water temperature drops with increased depth faster than it does in other layers

• boundary

Deep Water Ocean Temp.

• About 2°C

• Colder water is denser

Density

• density - the ratio of the mass to the volume

Density (cont.)

• Affected by salinity – dissolved solids add mass so, more salinity = higher density

• Affected by temperature – the colder it is the denser it is.

• Densest water at the poles

Color

• Determined by how it absorbs and reflects sunlight.

• Blue wavelength is reflected

• Phytoplankton absorb red and blue light, but reflect green light.