1. 200 m 1000 m Fig. 31.1 (EFB)

2. Ocean Productivity and Circulation: • Winds • countercurrents • Ekman spirals • Langmuir cells

3. Fig. 2.10 (EFB)

4. Ekman Spiral form in hours to days Fig. 31.5 (EFB)

5. Langmuir Cells form in minutes to hours Fig. 31.4 (EFB)

6. Ocean Productivity and Circulation: • Winds • countercurrents • Ekman spirals • Langmuir cells 2. Thermohaline circulation lower temperature + greater salinity = greatest density

8. Ocean Productivity and Circulation: • Winds • countercurrents • Ekman spirals • Langmuir cells 2. Thermohaline circulation 3. Upwelling

9. Upwelling Upwelling

10. Normal Conditions H H March – July position of high pressure zones Cold-water upwelling intensifies

11. Normal Conditions H H August - December position of high pressure zones Warm waters dominate inshore

12. Davidson Current El Niño Current

13. Davidson Current El Niño Current Aug-Dec shift

14. H H March shift in El Niño Southern Oscillation (ENSO) Cold-water upwelling absent

16. ENSO Early Warning Signs • Higher SSTs, track Kelvin wave W to E • Absence of cold-water upwelling on • California coast • Unusual marine organisms • barracudas, mako sharks, tropical fish to north • Failure of nesting seabirds

17. ENSO Global Impacts • Droughts in interior continents: • Southwest U.S., SE Asia, Australia, S. Africa • Floods in coastal CA, Peru • More tropical storms, hurricanes • in Pacific • Decline in fisheries

18. H H March shift in La Niña year following ENSO event Cold-water upwelling intensified

19. La Niña Global Impacts • Intensified cold-water upwelling • More tropical storms, hurricanes • in Atlantic • Increase in fisheries

21. ENSO in Antarctica = more sea ice = more productivity