The importance of nanoplankton within the pelagic Antarctic ecosystem

• Main Author: von Bröckel, Klaus
• Format: Article in Journal/Newspaper
• Language: English
• Published: Institut für Meereskunde 1981
• Subjects: Antarctic; Antarc*; Euphausia superba
• Online Access: https://oceanrep.geomar.de/id/eprint/56097/; https://oceanrep.geomar.de/id/eprint/56097/1/Broeckel_K_1981.pdf

During the Second German Antarctic Expedition 24 stations were visited from Januarv to February 1978 between Bellinghausen Sea and South Georgia. Samples were taken for the determination of phytoplankton composition and biomass as well as for protozooplankton biomass. Primary productivity was measured as 14C-uptake for different size classes of the phytoplankton population (< 20, 20-100 and 100-300 μm). Remarkable was the distribution of biomass and primary production within the different phytoplankton size classes. At nearly all stations the major part of the, biomass consisted of nanoplankton forms smaller than 20 μm which were responsible for about 90 % of the production. These tiny organisms were either diatoms (centric or pennate forms), μ-flagellates or dinoflagellates, thus representing the main phytoplankton groups. Protozooplankton cells were found at all stations, their biomass averaged about 16% of the phytoplanktion biomass. The obvious importance of nanoplankton forms as a food supplier for the krill (Euphausia superba) as well as the importance of protozooplankton as a food source and a food competitor for the krill during the Australian autumn are discussed.