Oceanography
Earth’s Oceans Earth is a special planet because of liquid water 71% of Earth’s surface is water Ocean divided by continents
4 Major Ocean Divisions Pacific Ocean Atlantic Ocean Indian Arctic Volume 724 million cubic kilometers Atlantic Ocean 322 million cubic kilometers Indian 292 million cubic kilometers Arctic 12 million cubic kilometers
Ocean Formation Two theories Out-gassing Big Splat Volcanic vents released gases that cooled to form our oceans Extraterrestrial comets delivered our water
Plate Tectonics Effect on Oceans Plate tectonics causes lithosphere to move As crust changes, oceans change shape 245 mya continents formed Pangaea Oceans formed Panthalassa
Characteristics of Ocean Water Chemical composition is similar to NaCl, Sodium Chloride, table salt Chlorine is the most abundant element Salinity Measured amount of salt and solids in a given amount of liquid
Factors affecting Salinity Evaporation Hot dry climate increases evaporation Less water more salt = high salinity River outlets/precipitation Increase of fresh water dilutes ocean water = lower salinity Currents Currents mix water causing water to become diluted = lower salinity
Temperature Zones Water Column: vertical aspect of ocean As depth Increases Pressure increases, Temperature decreases 3 Zones Surface Transition/Thermocline Deep zone
Surface Zone Warm top layer Extends down 300 meters Sunlight warms only top 100 meters How does zone maintain temperature? Average temp is 24°C Varies with latitude and time of year Rather swim near Alaska or Florida? Swim during summer or winter?
Transition/Thermocline Range is 300 to 700 meters Water temp decreases the greatest in this zone Begins at 24°C Ends at 5°C
Deep Zone Range 700 to ocean floor 1,200 Meters Average temp is 2°C 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: Condensation Gas to a liquid Precipitation Solid or liquid water falls to earth Evaporation Liquid to a gas