3. Ocean basins, currents, and climate change

4.  [CO 2 ] 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 CO 2 can dissolve into sea surface

5.  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

9.  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?

10. Factors influencing the volume of water in a basin relative to shorelines:  Size of basin  Amount of liquid water available  Density of water  Gravity

11.  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”

13. Blue: 180 MYBP

14.  Comets/meteorites: 0.1% water  Hydrologic cycle from continents (rivers)  Melting of ice  glaciers  polar ice  Thermal expansion

15.  Evaporation to atmosphere or to space  Freezing (importance of albedo)  “Snowball earth”  Positive feedback, “runaway” conditions  Compare to negative feedback carbonate-silicate cycle