Unit 5: OceanographyUnit 5: Oceanography

General InformationGeneral Information

• 70% of the world is covered by water

• Types of research– Core Samples– Mini Submarines– Satellites

Properties of WaterProperties of Water

• Density– Cold water is more dense than warm– Ice is less dense than liquid water

• BP= 100 C

• FP = 0 C

• Polarity– Water molecules have a (+ and — ) charge– Water molecules attract substances with ionic

bonds– Water with dissolved ions is called a solution

Properties of Ocean WaterProperties of Ocean Water

• Dissolved Ions– Chlorine and Sodium– Salinity refers to the amount of dissolved salt– Salinity increases the density of water

• Salinity varies slightly from place to place– Evaporation increases salinity– Freshwater decreases salinity

Temperature ProfileTemperature Profile

• Surface– Water is mixed by wind– Temperature is relatively uniform

• Middle Zone– Thermocline: a rapid drop in temperature

• Deep Water– Cold near freezing

Ocean LifeOcean Life

• Phytoplankton : single celled plants

• Zooplankton: single celled animals

Ocean FloorOcean Floor

• Ocean Floor : Methods of Study– Sonar: Bounce sound waves off bottom– Core Sample: study of ocean floor– Satellites: detect changes in the surface of

ocean water

Ocean FloorOcean Floor

• Continental Margin– Continental Shelf: extension of continent– Continental Slope: where shelf drops into ocean

basin– Continental Rise: sediment buildup at the

bottom of the basin– Submarine Canyon: eroded into slope by

turbidity currents

Active and Passive MarginActive and Passive Margin

Submarine CanyonSubmarine Canyon

Ocean FloorOcean Floor

• Ocean Basin– Abyssal Plain ; flattest area of ocean floor– Deep sea trench: formed at subduction

boundary– Seamounts and Guyots: mountains that rise

from the ocean floor– Mid-Ocean Ridge- center of seafloor spreading

Transform faultsTransform faults

Formation of an AtollFormation of an Atoll

Ocean Floor sedimentsOcean Floor sediments

• Terrigenous: (nonliving) sand, mud and clay

• Biogenious: (living) made up of microscopic shells

• Hydrogenous: formed by a chemical reaction causing sediment to precipitate out of water

The Movement of Ocean WaterThe Movement of Ocean Water

• The Movement of Ocean Water• Ocean current: any continuous flow of ocean

water• Winds drive Surface Currents

– Clockwise in the Northern Hemisphere– Counterclockwise in the Southern Hemisphere– Warm Currents originate at the equator– Cold currents originate at the poles– Countercurrents flow in opposite direction from

windblown currents

The Movement of Ocean WaterThe Movement of Ocean Water

• Currents Under The surface– Density Currents

• Move slowly• Caused by: temperature, sediments(turbidity) and

evaporation

– Cold waters from the poles create density currents

– Evaporation in the Mediterranean creates density currents

– Upwelling: caused by winds parallel to shore

TidesTides

• Created by the pull of gravity from the moon and sun

• Spring tide: highest tide

• Neap tide: lowest tide