Spatial distribution of phytoplankton in the eastern part of the North ...

was represented by 6 species, with themost common species, being Nitzschialongissima and N. constricta. Alongthe transect, distinct changes inNitzschia abundance was observed.Whereas all species were observed inthe western part, only N. longissimaoccurred on the eastern side of thetransect (Fig. 10).Figure 10. Spatial variation in the relative abundance‣ Dinophyceae – A total of 44 of Nitzschia species.different species of dinoflagellates were found in the transect. The most abundant species wereAlexandrium tamarense in the western part, Protoperidinium achromaticum and Diplopelta bombain the eastern part, and Pentapharsodinium dalei at all stations along the transect with maximumabundance in the central area. At all stations, Minuscula bipes, Protoperidinium pellucidum andZygabikodinium lenticulatum occurred in relatively constant abundance.Most of the dinoflagellate species found belong to the thecate genera Ceratium andProtoperidinium (only 5 athecate species were found). In total, 7 species of Ceratium occurred inthe transect, with a distinct gradient of abundance. All 7 species were found in the central area,while no species of this genus were found at two stations in the western part of the transect (Fig.11). A similar decrease in number of species was noted in the eastern end of transect, where only 2species occurred.With 17 species found, the genusProtoperidinium was the richest genusof algae, and was found throughout thetransect. P. achromaticum, the mostnumerous species, was very abundantat stations 143 and 145, located nearthe coast. After Thalassionemanitzschioides, P. achromaticum was Figure 11. Spatial variation in the relative abundanceof Ceratium species.the second most dominant alga inthese samples. However, there were no cells found at the western end of the transect. Interestingly,only P. pellucidum occurred at all stations along the transect. All other species appeared either in14