BASIC OCEANOGRAPHY

Ocean basins, currents, and climate change

Sea water and carbon cycles

[CO2] equilibrium at sea surface Reactions with H+ and OH- ions

Step 1: carbonic acid Step 2: carbonic acid to H+ and bicarbonate Step 3: bicarbonate to H+ and carbonate

ion Carbonate + Calcium incorporated into

shells of organisms (aragonite, calcite) Insoluble shells sink More CO2 can dissolve into sea surface

Biological Sequestration of CO2

Very small scale chemical reactions

Small scale biological processes Aggregation to large scale

movements of carbon Influences very large scale

ocean patterns and climate on a global scale

IPCC predictions for oceans

Ocean Habitats

Physiography of Ocean Basins

Oceans and Climate Change

What factors influence sea level? What factors influence sea

temperatures? How do atmospheric conditions alter

currents? How do currents influence

atmospheric conditions? How can reliable predictions be

made?

Sea Level ~ Ocean VolumeFactors influencing the volume of water

in a basin relative to shorelines: Size of basin Amount of liquid water available Density of water Gravity

Size of Ocean Basins Plate tectonics: components

solid plates of rock over semi-fluid (hot) magma plates can be lighter granitics or heavier basalts

Plate tectonics: processes Spreading where magma emerges between

plates Subduction where spreading plates are pushed

under neighboring plates Uplift where plates collide and rise

Dynamic Equilibrium – but changing ocean sizes over “geologic time scales”

Blue: 180 MYBP

Volume of liquid water – Additions

Comets/meteorites: 0.1% water Hydrologic cycle from continents

(rivers) Melting of ice

glacierspolar ice

Thermal expansion

Amount of liquid water – Losses

Evaporation to atmosphere or to space

Freezing (importance of albedo)“Snowball earth”Positive feedback, “runaway”

conditionsCompare to negative feedback

carbonate-silicate cycle