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

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Presentation on theme: "Dynamics of the Subarctic Gyre and physical/biological interactions Svein Sundby EUR-OCEANS BASIN Workshop, Reykjavík, 12 – 14 March 2005."— Presentation transcript:

1 Dynamics of the Subarctic Gyre and physical/biological interactions Svein 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 Linear responseNon-linear respons 1Non-linear respons 2 Ottersen et al. (2004) Ecosystem responses to climate change

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

5 Gjevik et al. (1995)

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

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

8 Sundby (2000)

9 Rothschild (1998)

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

11

12

13 TemperatureCod recruitment Calanus finmarchicusCod recruitment ADVECTION ATLANTIC 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 Sundby (2000) Change in advection along a negative temperature gradient Change in advection along the isolines of temperature Change in advection along a positive temperature gradient

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

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)

20

21 Dooley et al. (1984) 1970s GSA

22 Low Salinity Anomalies 70s80s90s High Salinity Anomalies 60s80s

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

24 Kola Rockall Fylla Newfoundland Salinity in the Subpolar Gyre

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

26

27

28 High and Low Salinity Anomalies of the Subarctic Gyre

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

30 NAO and the Atlantic water temperature in the Barents Sea

31 Climate Anomalies during the beginning of the 20 th century

32 R 2 = 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 Sundby (2000) Calanus finmarchicus in relation to the circulation of the Subartic Gyre

35 1973-99

36 Atlantic inflow Norwegian Sea intermediate water Norwegian Coastal Current

37 Norwegian Sea Intermediate Water Atlantic Water

38 R 2 = 0,27 Mean abundance of C. finmarchicus at B1 vs the deep water temperature in the Norwegian Trench


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