Phytoplankton change in the North Atlantic

A marked increase in global temperature over the last century was confirmed by the second Assessment Report of the Intergovernmental Panel on Climate Change. Here we report significant positive and negative linear trends from 1948 to 1995 in phytoplankton measured by the Continuous Plankton Recorder survey in the northeast Atlantic and North Sea that might reflect a response to changing climate on a timescale of decades. Spreading of unusually cold waters from the Arctic might have contributed to the decline in phytoplankton north of 59o N. Further south, phytoplankton season length and abundance seem to have increased.

A change in the zooplankton of the central North Sea (55 degree to 58 degree N): A possible consequence of changes in the benthos

The mesozooplankton taken in continuous plankton recorder samples from the Central North Sea has changed from being numerically dominated by holoplanktonic calanoid copepod species from 1958 to the late 1970s to a situation where pluteus larvae of echinoid and ophiuroid echinoderms have been more abundant than any single holoplanktonic species in the 1980s and early 1990s. The abundance of the echinoderm larvae as a proportion of the zooplankton taken in the samples has followed a continuous increasing trend over the Dogger Bank, but off the eastern coast of northern England and southern Scotland the increase did not become obvious until the 1980s. This trend is consistent with reported increases in abundance of the macrobenthos. It is proposed that changes in the benthos have influenced the composition of the plankton.