20.1 Ocean Water Properties (physical….) (…and chemical.)

Composition of Ocean water 96.5% pure water Dissolved solids (salts) - Cl, Na, Mg, S, Ca, K - mostly from river runoff Dissolved gases -N 2, O 2, CO 2 -From river runoff, atmosphere and undersea volcanoes -Polar areas have more dissolved gas than tropical areas

Salinity The amount of dissolved solids in a liquid Measured in parts per thousand; # of grams of the solid in 1 kg of H2OH2O Ocean water is 35 parts per thousand salt or 3.5% salt

Factors Affecting Salinity FreezingIncreasesWater freezes leaving salt behind PrecipitationDecreasesDilutes surface water (Tropics) EvaporationIncreaseWater evaporates leaving salt behind (Equator) River RunoffDecreaseDilutes surface water DepthIncreaseEvaporation at surface makes in salty at top and less as you go deeper

The RED SEA The BALTIC SEA! Hot…High evap rate… SALTY!! Cool…low evap rate, lots of runoff… NOT SALTY!! Verses

OCEAN WATER TEMPERATURE * the IR rays of the SUN heat the ocean waters. * the mixing effect distributes the solar heat down to 300 m. Tropics surface 30 o C Polar surface -2 o C (pack ice forms…) Middle lattitudes, surface temps vary

Thermocline Zone of rapid temp. change Caused by warm/cold barrier Waters can’t mix due to differences in density

Density Affected by salinity and temperature Cold = more dense Warm = less dense Densest water in polar regions

Color Ocean water appears blue because only blue light is reflected. The other colors are absorbed. Appears blue down to 100m. If you go deeper it is black