Interannual Time Scales: ENSO Decadal Time Scales:

1. Marine Ecosystems and Climate Variability Interannual Time Scales: ENSO Decadal Time Scales: Basin Wide Variability (e.g. Pacific Decadal Oscillation, North Atlantic Oscillation) Longer Time Scales: Warming trend

2. ENSO A SST Anomalies – Jan 1998 Less upwelling Less primary production Less CO2 flux out of the ocean Warm Phase B SST Anomalies – Dec 1999 More upwelling More primary production More CO2 flux out of the ocean Pt. 1 Cold Phase Pt. 2 y Pt. 3 x ºC

3. Marine Ecosystems and Climate Variability Interannual Time Scales: ENSO Decadal Time Scales: Basin Wide Variability (e.g. Pacific Decadal Oscillation, North Atlantic Oscillation) Longer Time Scales: Warming trend

4. Marine Ecosystems and Climate Variability PACIFIC OCEAN Decadal scale variations

5. Sardine Eggs (source: Checkley et al., 2000) Point Conception Changes in Fish abundance is driven by the variability of hydrographic conditions

6. Regional indices of Climate variability PACIFIC OCEAN

7. Most of the regional indices reflectlarge-scale climate variations in the North Pacific they can be summarized Pacific Decadal Oscillation Index

8. Currents SST

9. January Mean Sea Level Pressure

10. Mean Sea Level Pressure Negative Phase Positive Phase

11. Mean Sea Level Pressure Anomaly PDO Negative Phase Anomaly PDO Positive Phase

12. SST Anomalies Anomaly PDO Negative Phase SST Anomalies Anomaly PDO Positive Phase

13. Pacific Decadal Oscillation

14. + - +

15. Large-scale indices of Climate variability PACIFIC OCEAN ..and biology 1976 Regime Shift ?

16. WARM PHASE of PDO

17. COLD PHASE of PDO

18. Transitions in the Ecosystem may by nonlinear and sudden. There could be predictive skill (in terms of climate change) in monitoring closely the ecosystem

19. Observations along the California Coast

22. Population Dynamics Phytoplankton Zoo- plankton Abundance

23. A simple Ecosystem model Physical Environment NO3 NH4 Phyto Zoo Detritus

24. The seasonal cycle of the simple model

25. Increasing nutrient supply Seasonal cycles

26. A simple Ecosystem model Physical Environment NO3 NH4 Phyto Zoo Fish and Higher Trophic Levels Detritus HUMANS

27. Historical Overfishing and the Recent Collapse of Coastal Ecosystems Jackson et al., Science, Vol 293, Issue 5530, 629-637 , 27 July 2001 KELP FOREST

28. Historical Overfishing and the Recent Collapse of Coastal Ecosystems and more comlpex… Jackson et al., Science, Vol 293, Issue 5530, 629-637 , 27 July 2001 Coral Reefs

29. A simple Ecosystem model Physical Environment NO3 NH4 Phyto Zoo Fish and Higher Trophic Levels Detritus GLOBAL WARMING and Carbon Cycle HUMANS

30. End of lecture

31. Short Climate Variability occurs in all oceans Aleutian Low

32. What is the North Atlantic Oscillation ? • A sea saw of atmospheric mass which alternates between the polar and subtropical regions. • Changes in the mass and pressure fields lead to variability in the strength and pathway of storm systems crossing the Atlantic from the US East coast to Europe. • The NAO is most noticeable during the winter season (November - April) with maximum amplitude and persistence in the Atlantic sector. Martin Visbeck 4 November, 2014

33. The North Atlantic Oscillation Index • An Index can be constructed that represents the phase of the NAO. Most commonly the NAO index is based on the surface pressure (SLP) difference between the Subtropical (Azores) high and the Subpolar (Island) low. • Very often the pressure readings from two stations one on Iceland and the other either the Azores, Lisbon or Gibraltar are used to construct the NAO index. The twice daily reading are averaged from November through March and the difference in then the winter NAO index. Martin Visbeck 4 November, 2014

34. The North Atlantic Oscillation Index • The NAO index shows large variations from year to year. This interannual signal was especially strong during the end of the 19th century. • Sometimes the NAO index stays in one phase phase for several years in a row. This decadal variability was quite strong at the beginning and end of the 20th century. • One might also interpret the recent 30 years as a trend in the NAO index possibly linked to "global warming". Martin Visbeck 4 November, 2014

35. The positive NAO index phase • The positive NAO index phase shows a stronger than usual subtropical high pressure center and a deep than normal Icelandic low. • The increased pressure difference results in more and stronger winter storms crossing the Atlantic Ocean on a more northerly track. • This results in warm and wet winters in Europe and in cold and dry winters in northern Canada and Greenland. • The eastern US experiences mild and wet winter conditions. Martin Visbeck 4 November, 2014

36. The negative NAO index phase • The negative NAO index phase shows a weak subtropical high and weak Icelandic low. • The reduced pressure gradient results in fewer and weaker winter storms crossing on a more west-east pathway. • They bring moist air into the Mediterranean and cold weather to northern Europe. • The US east cost experiences more cold air outbreaks and hence snowy winter conditions. • Greenland, however, will have milder winter temperatures. Martin Visbeck 4 November, 2014

38. North Altantic Oscillation

39. Reading/Homework assignment:

42. What is interesting about the relationship between Climate and Ocean Biology? • Examples: • Fisheries and food • Global Warming problem • Preservation of species

43. An example 1) The Pacific Decadal Oscillation and ecosystem responses 2) Understanding the ecosystem response with models 3) The North Atlantic Oscillation and ecosystem responses

46. Abundance Reached at equilibrium Nitrate Concentration

47. Oscillation begin Oscillation stop hysteresis Abundance Days

48. Limit cycles The ecosystem may become Very unpredictable