Abstract
The European shelf seas can be divided into regions which have tidally mixed waters and thermally stratified waters. The tidally mixed near shore environments support zooplankton communities dominated by smaller copepods and having large meroplankton contributions. These small copepods (Centropages spp., Temora spp., Acartia spp., Paral Pseudo/Microcalanus spp.) together with the microzooplankton component form a different and more complex food web than the larger copepod/diatom link associated with thermally stratified waters. The copepods Calanus finmarchicus and C. helgolandicus account for over 90% of the copepod dry weight biomass in stratified waters. Although occurring in lower numbers in mixed waters they can still make significant contributions to the biomass. A 31 year time series from the European shelf shows the inter- and intea-annual variability of these species. The basic biology and food web that these two systems support, and the transfer of energy, can result in marked differences in quantity and quality of particulates available as food for fish larvae. Calanus dominated systems allow the primary production to be directed straight through the trophic food chain (diatoms/Calanus/fish larvae) while the near shore communities of smaller copepods limit the amount of energy being transferred to the higher trophic levels. Eighty-two Longhurst Hardy Plankton Recorder hauls were used as the data base for this study. In all cases the zooplankton was dominated by copepods both in numbers and biomass accounting for > 80% of total zooplankton dry weight in the Irish Sea, Celtic Sea, shelf edge of the Celtic Sea and the northern and southern North Sea in Spring.
Similar content being viewed by others
References
Cushing, D. H., 1989. A difference in structure between ecosystems in strongly stratified and in those weakly stratified. J. Plankton Res. 11: 1–13.
GLOBEC, 1991. Initial Science Plan. (Report No. 1.) Joint Oceanographic Institutions Inc., Washington DC, 93 pp.
GLOBEC, 1991. Northwest Atlantic Program. (Report No. 2.) Joint Oceanographic Institutions Inc., Washington DC, 93 pp.
GLOBEC, 1991. Workshop on Biotechnology Applications to Field Studies of Zooplankton. (Report No. 3.) Oceanographic Institutions Inc., Washington DC, 29 pp.
GLOBEC, 1993. Optics Technology Workshop Report. (Report No. 8.) Oceanographic Institutions Inc., Washington DC, 18 pp.
Joint, I. R. & R. Williams, 1985. Demands of the herbivore community on phytoplankton production in the Celtic Sea in August. Mar. Biol. 87: 297–306.
Lindley, J. A., 1986. Dormant eggs of calanoid copepods in seabed sediments of the English Channel and southern North Sea. J. Plankton Res. 8: 399–100.
Lindley, J. A., 1990. Distribution of overwintering calanoid copepod eggs in sea-bed sediments around southern Britain. Mar. Biol. 104: 209–217.
Lindley, J. A. & R. Williams, 1980. Plankton of the Fladen Ground during FLEX 76. II. Population dynamics and production of Thysanoessa inermis (Crustacea:Euphausiacea). Mar. Biol. 57: 79–86.
Longhurst. A. R. & R. Williams, 1976. Improved filtration systems for multiple-series plankton samples and their deployment. Deep-Sea Res. 23: 1067–1073.
Pingree, R. D. & D. K. Griffiths, 1978. Tidal fronts on the shelf seas around the British Isles. J. geophys. Res. 83: 4615–4622.
Poulet, S. A., 1976. Feeding of Pseudocalanus minutus on living and non-living particles. Mar. Biol. 34: 117–125.
Roman, M. R., 1984. Utilization of detritus by the copepod Acartia tonsa. Limnol. & Oceanogr. 25: 949–959.
Runge, J. A., 1988. Should we expect a relationship between primary production and fisheries? The role of copepod dynamics as a filter for trophic variability. Hydrobiologia, 167/168: 61–71.
Sherman, K., 1993. Large Marine Ecosystems as Global Units for Marine Resource Management: An Ecological Perspective. In K. Sherman, L. M. Alexander, B. D. Gold (eds), Large Marine Ecosystems, Stress, Mitigation and Sustainabilty. AAAS Press Washington DC, USA: 3–14.
Tester, P. A. & J. T. Turner, 1989. Zooplankton feeding ecology: Feeding rates of the copepods Acartia tonsa, Centropages velificatus and Eucalanus pileatus in relation to the suspended sediments in the plume of the Mississippi River (Northern Gulf of Mexico continental shelf. Scientia marina, 54: 321–237.
Williams, R., 1985. Vertical distribution of Calanus finmarchicus and C. helgolandicus in relation to the development of the seasonal thermocline in the Celtic Sea. Mar. Biol. 86: 145–149.
Williams, R. & N. R. Collins, 1986. Seasonal composition of meroplankton and holoplankton in the Bristol Channel. Mar. Biol. 92: 93–101.
Williams. R., D. V. P., Conway, N. R. Collins, 1983. The double LHPR system, a high speed micro- and macraplankton sampler. Deep-Sea Res. 30: 331–342.
Williams, R. & D. V. P. Conway (submitted). The ecosystem, Copepods and influence on fish recruitment in the Irish and North Seas.
Williams, R. & N. Fragopoulu, 1985. Vertical distribution and nocturnal migration of Nyctiphanes couchi (Crustacea: Euphausiacea) in relation to the summer thermocline in the Celtic Sea. Mar. Biol. 89: 257–262.
Williams, R. & J. A. Lindley, 1980a. Plankton of the Fladen Ground during FLEX 76 I. Spring Development of the Plankton Community. Mar. Biol. 57: 73–78.
Williams, R. & J. A. Lindley, 1980b. Plankton of the Fladen Ground during FLEX 76. 111. Vertical distribution, population dynamics and production of Calanus finmarchicus (Crustacea:Copepoda). Mar. Biol. 60: 47–56.
Williams, R., J. A., Lindley, H. G., Hunt & N. R. Collins, 1993. Plankton community structure and geographical distribution in the North Sea. J. exp. mar. Biol. Ecol. 172 (1/2): 143–156.
Williams, R. & D. B. Robins, 1982. Effects of preservation on wet weight, dry weight, nitrogen and carbon content of Calanus helgolandicus (Crustacea:Copepoda). Mar. Biol. 71: 271–281.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Williams, R., Conway, D.V.P. & Hunt, H.G. The role of copepods in the planktonic ecosystems of mixed and stratified waters of the European shelf seas. Hydrobiologia 292, 521–530 (1994). https://doi.org/10.1007/BF00229980
Issue Date:
DOI: https://doi.org/10.1007/BF00229980