Seasonal energy requirements of macrozooplankton from Kosterfjorden, Western Sweden

• Main Author: Båmstedt, U.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Institut für Meereskunde 1981
• Subjects: Calanus finmarchicus
• Online Access: https://oceanrep.geomar.de/id/eprint/56089/; https://oceanrep.geomar.de/id/eprint/56089/1/Bamstedt_U_1981.pdf

A study on the macroplankton community in Kosterfjorden, Western Sweden, is used to introduce a term called Index of population energy-flow, lpef. This term is defined as the ratio between the energy flow (consumption) through a specific population and the flow through the whole trophic level to which the species belongs. For simplicity, the study is restricted to 6 herbivorous and omnivorous species and 7 carnivorous species. Values for the production, respiration, and excretion are calculated from published data and are presented as means for each of the four seasons. On an annual basis between 8 and 52 % of the assimilated energy is bound in production, between 30 and 85% is used in respiration, and between 6 and 32% is excreted. the estimated grazing pressure of the 6 herbivorous/omnivorous species is relatively low compared with the estimated primary production, especially during spring and summer, indicating that most of the primary production goes directly to the benthic community. The copepod Calanus finmarchicus has the highest index of population energy-flow among herbivorous/omnivorous species with an annual mean of 87% and seasonal maximum in autumn (lpef = 96%). The copepod Metridia longa is most important in spring (lpef = 16%) and the three euphausiid species in summer (lpef = 4-5%). Among carnivores the copepod Chiridius armatus has the highest annual mean value (lpef = 43%) with seasonal maximum in spring (lpef = 65%). Small chaetognaths are most important in autumn (lpef = 18%) and the polychaete Tomopteris helgolandica and the trachymedusa Aglantha digitale in winter (lpef = 33 % and 17%, respectively).