The Vertical and Seasonal Distribution of Dinoflagellates in the North Sea. II. Blyth 1973-1974 and Whitby 1975

Abstract

In a follow up of our earlier study, dinoflagellates from the site 8 km off Blyth were examined quantitatively for a further 22 mo. in 1973-1974. A very clear seasonal pattern emerged with an Aug. peak of 1.8 .times. 106 cells/m3 in 1973 and a lower peak of 5.2 .times. 105 cells/m3 in 1974. In both years Ceratium furca was the dominant species in the autumn and winter. In 1973 the spring and summer produced striking peaks of Dinophysis norvegica and Ceratium lineatum but in 1974 no species achieved very high numbers. At Whitby a more restricted sampling program revealed very striking differences in vertical distribution of the main dinoflagellate species. A total of 61 spp. were identified including the first records from British waters of Helgolandinum subglobosum, Spatulodinium pseudonoctiluca, Dissodium exdentricum and Protoperidinium sympholis.