Winter distribution of microzooplankton in the Nordic Seas

No abstracts are to be cited without prior reference to the author.

Winter investigations of both phytoplankton and microzooplankton in open oceans are few, hence we know very little about the processes taking place outside the traditional growth seasons. However, winter survival is crucial to all organisms, and to get a better understanding of the winter processes, cruises to the Nordic Seas were organized during two winter seasons (1999 and 2000). The purpose was primarily to study the connection between winter convection and phytoplankton, based on knowledge from a winter study of shelf areas in Northern Norway (Backhaus et al. 1999). From this study we knew that the deep convection was a vital process for initiation of the spring bloom in shallow areas. Now we wanted to investigate the effects on plankton in open oceans where the convective mixing was supposed to transport phytoplankton cells up and down in the water column and keeping them from sinking to the bottom in these deep areas. Additional to the phytoplankton we also collected microzooplankton in our samples, and that gave us an opportunity to include a study of the smallest zooplankton forms in relation to both convective mixing and phytoplankton distribution during winter