Underwater Video Profiler
Sergestes from UVP
Appendicularian from UVP
Date:June 12 2004
Author: Astthor Gislason, Marine Research Institute, Iceland and Marc Picheral, CNRS, Laboratoire d’Oceanologie de Villefranche, France
Through the night and until noon we steamed from the northern box towards the third station. Station operations began about noon with the deployment of the Åkra trawl. Another tow with the Macrozooplankton trawl, was started in the evening, and after that the Underwater Video Profiler (UVP) was deployed (photo).
At noon, incubations for egg production rates of the copepod Calanus finmarchcius, that were set up yeasterday, were completed. The results showed that egg production rates were slow (about 5 eggs per female per day), which agrees with results from the Icelandic Mar-Eco cruise last year in the same area and during the same time of year.
The UVP has been deployed to 1000m depth at each station. It quantifyes the vertical distribution of particles and gives us nice images of zooplankton. The top black and white image shows the deep-water shrimp Sergestes often caught by the trawls, and the bottom one is a rare in-situ image of a deep appendicularian (800m) leaving its dirty house (the left arrow shows the animal composed of the gonads, stomach and its moving tail while the right arrow indicates the filters). The appendicularians are extraordinary animals that build complex houses of mucous in which they filter small particles from the water. With time the filters become clogged and they move out from their house in order to build a new one.