A high frequency time series at weathership M, Norwegian Sea, during the 1997 spring bloom: feeding of adult female Calanus finmarchicus

The feeding ecology of Calanus finmarchicus was investigated during spring 1997 at a permanent station in the Norwegian Sea (Stn M, 66"N, 2"E) as part of the TASC (Trans Atlantic Study of Calanus finmarchicus) project time-series investigations. The phytoplankton bloom began in mid May, coinciding m t h the onset of the stratification, and was mainly composed of d~atoms and prymnesiophytes. Daily Ingestion of phytoplankton by C. finmarchicus was about 2% of body carbon for the long period before the bloom, 30% during the bloom and 14 % after the bloom. Due to their low abundance, ingestion of ciliates represented only 2 to 6 O/o of the phytoplankton ingestion. Body carbon and carbon/nitrogen ratio decreased significantly before the bloom indicating a deficit in carbon ingestion and the use of storage lipid during this period.