Oceanography

Earth’s Oceans Earth is a special planet because of liquid water Earth is a special planet because of liquid water 71% of earth’s surface is water 71% of earth’s surface is water Ocean divided by continents Ocean divided by continents

4 Major Ocean Divisions Pacific Ocean Pacific Ocean Volume 724 million cubic kilometers Volume 724 million cubic kilometers Atlantic Ocean Atlantic Ocean 322 million cubic kilometers 322 million cubic kilometers Indian Indian 292 million cubic kilometers 292 million cubic kilometers Arctic Arctic 12 million cubic kilometers 12 million cubic kilometers

Ocean Formation Two theories Two theories Out-gassing Out-gassing Big Splat Big Splat Out-gassing Out-gassing Volcanic vents released gases that cooled to form our oceans Volcanic vents released gases that cooled to form our oceans Big Splat Big Splat Extraterrestrial comets delivered our water Extraterrestrial comets delivered our water

Plate Tectonics Effect on Oceans Plate tectonics causes lithosphere to move Plate tectonics causes lithosphere to move As crust changes, oceans change shape As crust changes, oceans change shape 245 mya continents formed Pangaea 245 mya continents formed Pangaea Oceans formed Panthalassa Oceans formed Panthalassa

Characteristics of Ocean Water Chemical composition is similar to Chemical composition is similar to NaCl, Sodium Chloride, table salt NaCl, Sodium Chloride, table salt Chlorine is the most abundant element Chlorine is the most abundant element Salinity Salinity Measured amount of salt and solids in a given amount of liquid Measured amount of salt and solids in a given amount of liquid

Factors affecting Salinity Evaporation Evaporation Hot dry climate increases evaporation Hot dry climate increases evaporation Less water more salt = high salinity Less water more salt = high salinity River outlets/precipitation River outlets/precipitation Increase of fresh water dilutes ocean water = lower salinity Increase of fresh water dilutes ocean water = lower salinity Currents Currents Currents mix water causing water to become diluted = lower salinity Currents mix water causing water to become diluted = lower salinity

Temperature Zones Water Column: vertical aspect of ocean Water Column: vertical aspect of ocean As depth Increases As depth Increases Pressure increases, Temperature decreases Pressure increases, Temperature decreases 3 Zones 3 Zones Surface Surface Transition/Thermocline Transition/Thermocline Deep zone Deep zone

Surface Zone Warm top layer Warm top layer Extends down 300 meters Extends down 300 meters Sunlight warms only top 100 meters Sunlight warms only top 100 meters How does zone maintain temperature? How does zone maintain temperature? Average temp is 24°C Average temp is 24°C Varies with latitude and time of year Varies with latitude and time of year Rather swim near Alaska or Florida? Rather swim near Alaska or Florida? Swim during summer or winter? Swim during summer or winter?

Transition/Thermocline Range is 300 to 700 meters Range is 300 to 700 meters Water temp decreases the greatest in this zone Water temp decreases the greatest in this zone Begins at 24°C Begins at 24°C Ends at 5°C Ends at 5°C

Deep Zone Range 700 to ocean floor 1,200 Meters Range 700 to ocean floor 1,200 Meters Average temp is 2°C Average temp is 2°C Deepest part of the ocean is below zero, yet water doesn’t freeze, why? Deepest part of the ocean is below zero, yet water doesn’t freeze, why?

Water Cycle Cycle that links all Earth’s solid, liquid and gaseous water. 3 parts are: Cycle that links all Earth’s solid, liquid and gaseous water. 3 parts are: Condensation Condensation Gas to a liquid Gas to a liquid Precipitation Precipitation Solid or liquid water falls to earth Solid or liquid water falls to earth Evaporation Evaporation Liquid to a gas Liquid to a gas