Distribution of Synechococcus sp. and Synechococcus bacillaris in the waters of the Straits of Magellan (April 1995- early Austral Autumn).

During the last oceanographic cruise carried out in the Straits of Magellan (April 1995), a serological approach was used in order to determine the distribution and composition of the picophytoplankton community with respect to two cyanobacteria species, Synechococcus sp. and bacillaris, characterized respectively by phycoerythrin and phycocyanin as the main accessory photosynthetic pigment. In the period examined, the Straits were characterized by generally low concentrations of total picophytoplankton (10(5)-10(6) cells/l). The qualitative composition of the community showed the prevalence of the species Synechococcus sp. in the Pacific basin, whereas S.bacillaris appears to be predominant in the central area. The immunofluorescence method proved to be effective in the study of the diversity of these microorganisms in aquatic environments.