Nilsen, F. Geophysical Institute, University of Bergen,
Østerhus, S. Geophysical Institute, University of Bergen,
Mork, M. Geophysical Institute, University of Bergen,

Measurements made from the Weather Ship Polarfront and two subsurface moorings using a mini-CTD, Aanderaa weatherstation, Aanderaa RCM-7 and an RDI Acoustic Doppler Current Profiler (ADCP), provide a detailed look at the diurnal cycle of the upper ocean. The measurements where taken from 17 April to 9 July 1997 at the Ocean Weather Station Mike (OWSM). This station is situated in the Norwegian Sea, at 66 N 2 E, 2000 m depth, and has been employed as permanent weather station since 1948. Mike has been the site of important early works on plankton dynamics. However, many questions on the reproductive and feeding biology of zooplankton (Calanus finmarchicus) remain unanswered. Moored Acoustic Doppler Current Profilers are used to analyse the daily vertical zooplankton migration in connections with mixed layer dynamics. The estimated migration is compared to phytoplankton data taken in the same period with emphasise on the spring bloom period in May. Calculated acoustic backscatter and vertical velocity indicates daily vertical migration until the phytoplankton bloom begins. No time signal is observed after the bloom. Integrating the backscatter data and calibrating against Multinet zooplankton samples, will provide an estimate of the total biomass in the top 100 meters during the measuring period.
Day: Thursday, Feb. 4
Time: Poster
Location: Sweeney Center
Code: SS04TH0830S