Seasonal and interannual variability of size-fractionated phytoplankton biomass and community structure at station Kerfix, off the Kerguelen Islands, Antarctica

• Published in: Journal of Plankton Research
• Main Authors: Fiala, Michel, Kopczynska, Elzbieta E., Jeandel, Catherine, Oriol, Louise, Vetion, Giles
• Format: Text
• Language: English
• Published: Oxford University Press 1998
• Subjects: ORIGINAL ARTICLES; Southern Ocean; Kerguelen; Kerguelen Islands; Antarc*; Antarctica
• Online Access: http://plankt.oxfordjournals.org/cgi/content/short/20/7/1341; https://doi.org/10.1093/plankt/20.7.1341

Time series of phytoplankton biomass and taxonomic composition have been obtained for the 3 years 1992, 1993 and 1994 in the northern part of the Southern Ocean (station Kerfix, 50�40'S, 68�25;E) Autotrophic biomass was low throughout the year (<0.2 mg m−3 except during a short period in summer when a maximum of 1.2 mg chlorophyll (Chl) a m− was reached. During winter, the integrated biomass was low (<10 mg m−2) and associated with deeply mixed water, whereas the high summer biomass (>20 mg m−2) was associated with increased water column stability. During summer blooms, the >10 μ;m size fraction contributed 60% to total integrated biomass. Large autotrophic dinoflagellates, mainly Prorocentrum spp., were associated with the summer phyto plankton maxima and accounted for >80% of the total autotroph carbon biomass. In November and December, the presence of the large heterotrophic dinoflagellates Protoperidinium spp . and Gyro dinium spp. contributed a high proportion of total carbon biomass. During winter, the <10 μm size fraction contributed 80% of total Chi a biomass with domination of the picoplankton size fraction. The natural assemblage included mainly naked flagellates such as species of the Prasinophyceae, Cryptophyceae and Prymnesiophyceae. During spring, picocyanobacteria occurred in sub-surface water with a maximum abundance in September of 106 cells 1−1