Post on 22-Feb-2016
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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