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Detailed Reference Information |
Cowles, T.J. and Fessenden, L.M. (1995). Copepod grazing and fine-scale distribution patterns during the Marine Light-Mixed Layers experiment. Journal of Geophysical Research 100: doi: 10.1029/94JC02214. issn: 0148-0227. |
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The mesozooplankton in the upper 100 m at 59¿N, 21¿W were dominated by the copepodite stages of Calanus finmarchicus in both May and August 1991. Abundance of C. finmarchicus in the upper 20 m of the water column was 800 m-3 in May and 200 m-3 in August. Although hydrographic conditions changed from well mixed to stratified between May and August, the fine-scale vertical distribution pattern of C. finmarchicus was essentially the same during these two surveys of the Marine Light-Mixed Layers site. Copepodite stage five (CV) comprised a larger fraction of the population in August compared to May, however. Gut evacuation experiments with C. finmarchicus indicated that late copepodite and adult female life stages had evacuation rates of approximately 4% h-1 in both May and August. Although these evacuation rates are consistent with others measured for Calanus, the relatively low biomass in the upper 100 m resulted in an estimated daily grazing impact by Calanus of less than 5% of the phytoplankton standing stock in May, and less than 1% in August. The ingestion rates we measured suggest that the total grazing impact of all mesozooplankton grazers is less than 10% of daily primary production. These relatively low ingestion rates on phytoplankton provide these copepods with less than half of the total daily carbon intake required to balance estimated rates of respiration and growth in the field. In order to balance these metabolic costs, we estimate that the mesozooplankton would need to ingest the equivalent of at least 100% of the estimated microzooplankton/protist daily production. ¿ American Geophysical Union 1995 |
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BACKGROUND DATA FILES |
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Abstract |
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Keywords
Oceanography, Biological and Chemical, Plankton, Oceanography, Biological and Chemical, Ecosystems, structure and dynamics, Oceanography, Biological and Chemical, Trophodynamics, Oceanography, Biological and Chemical, Food chains |
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Publisher
American Geophysical Union 2000 Florida Avenue N.W. Washington, D.C. 20009-1277 USA 1-202-462-6900 1-202-328-0566 service@agu.org |
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