GEOL 150Lg Lecture Notes - Lecture 21: Volcanism, Water Mass, Ocean Current
Document Summary
Co2 follows glacial cycle: warm interstadials co2 released from oceans. Posiive feedback for warming: cold stadials co2 absorbed and stored in oceans: Posiive feedback for cooling: orbital cycles direct the climate change, co2 changes amplify climate change. Co2 lowers slowly during glaciaion; rises abruptly ater. High laitudes and deep oceans started to warm irst, then the tropics followed. Current hypotheses for co2 variability: deep ocean, isolated water mass stored dissolved co2. Deep ocean circulaion change may have triggered release of co2 from deep ocean water mass: geologic sources of co2. Biological pump there may have been more phosphate (plant nutrients) in the ocean during glaciaions. In southern ocean around antarcica, phosphate concentraions are high: perhaps southern ocean producivity was higher during glaciaions, iron from wind blown dust may have helped increase biological producivity in the southern ocean during glaciaions. When the southern ocean warms the northern ocean cools.
