Journal of the Marine Biological Association of the United Kingdom



Research Article

Molecular analysis of Continuous Plankton Recorder samples, an examination of echinoderm larvae in the North Sea


Richard R  Kirby a1c1 and John A.  Lindley a2
a1 School of Biological Sciences, University of Plymouth, Drake Circus, Plymouth, PL4 8AA, UK
a2 Sir Alister Hardy Foundation for Ocean Sciench, Citadel Hill, The Hoe, Plymouth, PL1 2PB, UK

Article author query
kirby rr   [PubMed][Google Scholar] 
lindley ja   [PubMed][Google Scholar] 

Abstract

Analysis of the biological time series of plankton samples collected by the Continuous Plankton Recorder (CPR) in the North Atlantic and North Sea has shown a regime shift in the plankton in this region. Both the distributions of planktonic organisms and their timing of occurrence in the seasonal cycle have changed and these changes appear to reflect global warming. In the North Sea the planktonic larvae of echinoderms have shown a recent dramatic increase in both relative and absolute abundance and their seasonal peak of occurrence has advanced by 47 days. The identity of the echinoderm larvae involved in this change has, however, remained equivocal. The small size of many organisms like echinoderm larvae combined with incomplete taxonomic keys hinders their visual identification and their fragility often means that useful morphological features are damaged during sampling by the CPR. Here, using new molecular methods applied to CPR samples, we show that planktonic larvae of the benthic Echinocardium cordatum dominate the North Sea plankton. We argue that since this species benefits from mild winters and warmer waters their numerical increase in the plankton is consistent with recent climatic changes that appear to be affecting the wider ecology of this region.

(Received October 14 2004)
(Accepted February 23 2005)


Correspondence:
c1 e-mail: r.kirby@mba.ac.uk