Outline

1. Dynamics of the Subarctic Gyre and physical/biological interactionsSvein Sundby EUR-OCEANS BASIN Workshop, Reykjavík, 12 – 14 March 2005

2. Outline • Regime shifts and hypothesis of advection of Calanus as the link between temperature and cod recruitment (Sundby 2000) • New interpretations on the GSAs (Sundby and Drinkwater 2005) - implications for advection • Some very preliminary results on abundance of Calanus finmarchicus in the North Sea and water masses in the Norwegian Trench.

3. Ecosystem responses to climate change Linear response Non-linear respons 1 Non-linear respons 2 Ottersen et al. (2004)

4. Calanus finmarchicus in relation to the circulation of the Subartic Gyre Sundby (2000)

5. Gjevik et al. (1995)

6. Mean ambient temperature for Calanus finmarchicus population in the North Atlantic (hibernation excluded). Sundby (2000)

7. Recruitment in Atlantic cod Temperature for optimal growth rate Planque and Frédou (1999)

8. Sundby (2000)

9. Rothschild (1998)

10. Calanus finmarchicus in relation to the circulation of the Subartic Gyre Sundby (2000)

13. ATLANTIC COD RECRUITMENT Temperature Cod recruitment ADVECTION Calanus finmarchicus Cod recruitment

14. Principal spatial features of Calanus finmarchicus, cod and temperature in the North Atlantic Sundby (2000)

15. Conceptual model for the combined advection of heat and Calanus finmarchicus from the deep-sea core production region onto the surrounding shelves with cod populations Change in advection along a positive temperature gradient Change in advection along the isolines of temperature Change in advection along a negative temperature gradient Sundby (2000)

16. Ecosystem responses to climate change Linear response Non-linear respons 1 Non-linear respons 2 Ottersen et al. (2004)

17. Regime shifts and hypothesis of advection of Calanus as the link between temperature and cod recruitment (Sundby 2000) • New interpretations on the GSAs (Sundby and Drinkwater 2005) - implications for advection • Some very preliminary results on abundance of Calanus finmarchicus in the North Sea and water masses in the Norwegian Trench.

18. Dickson et al. (1988)

19. Belkin et al. (1998)

21. 1970s GSA Dooley et al. (1984)

22. Low Salinity Anomalies 70s 80s 90s High Salinity Anomalies 60s 80s

23. Temperature in Kola Section and Inverted Ice Index in Davis Strait Annual Mean 3-yrs Run. Mean

24. Salinity in the Subpolar Gyre Kola Fylla Rockall Newfoundland

25. u .S = K 2S S/t = u .S - K 2S > 0

28. High and Low Salinity Anomalies of the Subarctic Gyre

29. 1960/70s GSA in the Northwest Atlantic A high salinity anomaly in the Northwest Atlantic A high salinity anomaly of the Northeast Atlantic Mid 70s GSA in the Northeast Atlantic

30. NAO and the Atlantic water temperature in the Barents Sea

31. Climate Anomalies during the beginning of the 20th century

32. R2 = 0,13

33. Regime shifts and hypothesis of advection of Calanus as the link between temperature and cod recruitment (Sundby 2000) • New interpretations on the GSAs (Sundby and Drinkwater 2005) - implications for advection • Some very preliminary results on abundance of Calanus finmarchicus in the North Sea and water masses in the Norwegian Trench.

34. Calanus finmarchicus in relation to the circulation of the Subartic Gyre Sundby (2000)

35. 1973-99

36. Norwegian Coastal Current Atlantic inflow Norwegian Sea intermediate water

37. Atlantic Water Norwegian Sea Intermediate Water

38. Mean abundance of C. finmarchicus at B1 vs the deep water temperature in the Norwegian Trench R2 = 0,27