Publication Abstract

Is observed variability in thelong-term results of the CPR survey a response to climate change?

P.C. Reid, B. Planque and M. Edwards

Inthe more than 50 years that the Continuous Plankton Recorder (CPR) survey has operated ona regular monthly basis in the north-east Atlantic and North Sea, large changes have beenwitnessed in the planktonic ecosystem. These changes have taken the form of long-termtrends in abundance for certain species or stepwise changes for others, and in many casesare correlated with a mode of climatic variability in the North .Atlantic, either: (1) theNorth Atlantic Oscillation (NAO), a basin-scale atmospheric alteration of the pressurefield between the Azores high pressure cell and the Icelandic Low; or (2) the Gulf StreamIndex (GSI), which measures the latitudinal position of the north wall of the Gulf Stream.Recent work has shown that the changes in the GSI are coupled with tile NAO and PacificSouthern Oscillation with a ? year lag. The plankton variability is also possibly linkedto changes observed in the distribution and flux of water masses in the surface,intermediate and deep waters of the North Atlantic. For example, in the last two decades,the extent and location of the formation of North Atlantic Deep Water, Labrador SeaIntermediate Water and Norwegian Sea intermediate and upper-layer water has alteredconsiderably. This paper discusses the extent to which observed changes in planktonabundance and distribution may be linked to this basin-scale variability in hydrodynamics.The results are also placed within the context of global climate warming and the possibleeffects of the observed melting of Arctic permafrost and sea ice on the subpolar NorthAtlantic.

Reference:

P.C. Reid, B. Planque and M. Edwards, 1998. Is observed variability in the long-termresults of the CPR survey a response to climate change? Fisheries Oceanography, 7:282-288.