CPR Results: the Changing Northeast Atlantic
(^) Early reports from the CPR study were vague, mostly couched in statistical constructs
difficult to interpret as specific changes in biology. More-recent work initiated by
Frédéric Ibanez and colleagues has clarified things. The situation varies by region
(Fig. 16.17). North and east of Britain, the stock of the dominant, large herbivorous
copepod, Calanus finmarchicus, has varied inversely with the NAO, a measure of
wind strength across the North Atlantic (Fig. 16.18a). The NAO is the difference in
barometric pressure between the Icelandic low and Azores high. When NAO is high,
winds pushing the Gulf Stream east are strong. When it is low, the winds are weaker.
The whole distribution of wind over the region changes between high NAO and low
NAO (Fig. 16.18b & c). In the “low” pattern, flow into northern European waters is
from farther north, the locus of the C. finmarchicus stock, and is colder and weaker. In
the “high” pattern, flow is from farther south and carries more and warmer waters
toward Scotland and Norway. The NAO moved from the 1960s to 1990s toward
stronger NAO, toward a warmer Europe. The zooplankton along the recorder routes in
the northern North Sea and northwest of Scotland became more and more constituted
of species with southern affinities. Particularly, in the North Sea, abundance changes