Trans-Atlantic responses of Calanus finmarchicus populations to basin-scale forcing associated with the North Atlantic Oscillation☆

Populations of the copepod species Calanus finmarchicus often dominate the springtime biomass and secondary production of shelf ecosystems throughout the North Atlantic Ocean. Recently, it has been hypothesised that interannual to interdecadal fluctuations observed in such populations are driven primarily by climate-associated changes in ocean circulation. Here, we compare evidence from the North Sea and Gulf of Maine/Western Scotian Shelf (GoM/WSS) linking fluctuations in C. finmarchicus abundance to changes in ocean circulation associated with the North Atlantic Oscillation (NAO). A particularly striking contrast emerges from this Trans-Atlantic comparison: whereas the North Sea C. finmarchicus population exhibits a negative correlation with the NAO index, the GoM/WSS population exhibits a more complex, positive association with the index. The physical processes underlying these contrasting population responses are discussed in the context of regional- to basin-scale circulation changes associated with the NAO.

[1]  R. Pickart,et al.  Mean Structure and Interannual Variability of the Slopewater System South of Newfoundland , 1999 .

[2]  Bob Dickson,et al.  From the Labrador Sea to global change , 1997, Nature.

[3]  T. Stocker,et al.  North atlantic oscillation dynamics recorded in greenland ice cores , 1998, Science.

[4]  Uwe Ulbrich,et al.  A shift of the NAO and increasing storm track activity over Europe due to anthropogenic greenhouse gas forcing , 1999 .

[5]  B. Planque,et al.  Is observed variability in the long-term results of the Continuous Plankton Recorder survey a response to climate change? , 1998 .

[6]  D. Sameoto.  Decadal changes in phytoplankton color index and selected calanoid copepods in continuous plankton recorder data from the Scotian Shelf , 2001 .

[7]  Meteorology: Oscillating opinion , 2000, Nature.

[8]  R. Curry,et al.  Oceanic transport of subpolar climate signals to mid-depth subtropical waters , 1998, Nature.

[9]  P. Jones,et al.  The Evolution of Climate Over the Last Millennium , 2001, Science.

[10]  Zong-ci Zhao,et al.  Climate change 2001, the scientific basis, chap. 8: model evaluation. Contribution of Working Group I to the Third Assessment Report of the Intergovernmental Panel on Climate Change IPCC , 2001 .

[11]  P. C. Reid,et al.  Pulses in the eastern margin current and warmer water off the north west European shelf linked to North Sea ecosystem changes , 2001 .

[12]  J. Stephens,et al.  The effects of fluctuations in North Sea flows on zooplankton abundance , 1998 .

[13]  J. Mauchline.  The biology of calanoid copepods , 1998 .

[14]  R. Seed.  Ecological Geography of the Sea. Alan Longhurst , 2000 .

[15]  Keith W. Dixon,et al.  Anthropogenic Warming of Earth's Climate System , 2001, Science.

[16]  E. Svendsen,et al.  A regime shift in the North Sea circa 1988 linked to changes in the North Sea horse mackerel fishery , 2001 .

[17]  Tom Rossby,et al.  Slow variations in mean path of the Gulf Stream east of Cape Hatteras , 2000 .

[18]  T. Barnett,et al.  Detection of Anthropogenic Climate Change in the World's Oceans , 2001, Science.

[19]  A. J. Southward,et al.  Plankton and Productivity in the Oceans , 1964 .

[20]  J. Hurrell.  Decadal Trends in the North Atlantic Oscillation: Regional Temperatures and Precipitation , 1995, Science.

[21]  B. Planque,et al.  Predicting Calanus Finmarchicus Abundance from a Climatic Signal , 1998, Journal of the Marine Biological Association of the United Kingdom.

[22]  R. Fairbanks,et al.  Interannual variability of boundary fluxes and water mass properties in the Gulf of Maine and on Georges Bank: 1993–1997☆☆☆ , 2001 .

[23]  M. Heath,et al.  Climate fluctuations and the spring invasion of the North Sea by Calanus finmarchicus , 1999 .

[24]  Robert R. Dickson,et al.  Long-term coordinated changes in the convective activity of the North Atlantic , 1996 .

[25]  J. Houghton,et al.  Climate change 2001 : the scientific basis , 2001 .

[26]  M. Noguer,et al.  Climate change 2001: The scientific basis. Contribution of Working Group I to the Third Assessment Report of the Intergovernmental Panel on Climate Change , 2002 .

[27]  C. Greene,et al.  The response of Calanus finmarchicus populations to climate variability in the Northwest Atlantic: basin-scale forcing associated with the North Atlantic Oscillation , 2000 .

[28]  S. Østerhus,et al.  Decreasing overflow from the Nordic seas into the Atlantic Ocean through the Faroe Bank channel since 1950 , 2001, Nature.

[29]  P. C. Reid,et al.  Oceanographic Responses to Climate in the Northwest Atlantic , 2001 .

[30]  S. Piontkovski,et al.  Seasonal and interannual dynamics of Calanus finmarchicus in the Gulf of Maine (Northeastern US shelf) with reference to the North Atlantic Oscillation , 2001 .

[31]  C. Hannah,et al.  Decadal-scale hydrographic and circulation variability in the Scotia–Maine regionSUM ☆ ☆☆ , 2001 .

[32]  J. Jossi,et al.  Zooplankton trends: US north-east shelf ecosystem and adjacent regions differ from north-east Atlantic and North Sea , 1993 .

[33]  Jonathan M. Gregory,et al.  Changing spatial structure of the thermohaline circulation in response to atmospheric CO2 forcing in a climate model , 1999, Nature.

[34]  B. Planque,et al.  Calanus and environment in the eastern North Atlantic. 2. Role of the North Atlantic Oscillation on Calanus finmarchicus and C. helgolandicus , 1996 .

[35]  B. Planque,et al.  Long-term changes in zooplankton and the climate of the North Atlantic , 1998 .

[36]  R. Heyman,et al.  A Comparative Atlas of Zooplankton: Biological Patterns in the Oceans , 1983 .

[37]  A. Weaver,et al.  Absence of deep-water formation in the Labrador Sea during the last interglacial period , 2001, Nature.

[38]  J. Hurrell,et al.  The North Atlantic Oscillation , 2001, Science.

[39]  E. Head,et al.  Distribution of Calanus spp. on and around the Nova Scotia Shelf in April : evidence for an offshore source of Calanus finmarchicus to the central and western regions , 1999 .

[40]  H. Hirche.  Diapause in the marine copepod, Calanus finmarchicus — A review , 1996 .

[41]  M. Hoerling,et al.  Tropical Origins for Recent North Atlantic Climate Change , 2001, Science.