A high frequency time series at weathership M, Norwegian Sea, during the 1997 spring bloom: feeding of adult female Calanus finmarchicus
Xabier Irigoien1,*, Robert Head1, Ulrike Klenke2, Bettina Meyer-Harms1, Derek Harbour1, Barbara Niehoff2, Hans-Jürgen Hirche2, Roger Harris1
1Plymouth Marine Laboratory, Prospect Place, Plymouth, PL1 3DH, United Kingdom
2Alfred Wegener Institute for Polar and Marine Research, D-27656 Bremerhaven, Germany
ABSTRACT: 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 with the onset of the stratification, and was mainly composed of diatoms 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% 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.
KEY WORDS: Calanus finmarchicus · Norwegian Sea · Feeding · Phytoplankton · Ciliates