The Composition and Structure of Phytoplankton in the Busse Lagoon, Southeastern Sakhalin Island

AbstractThe species composition, quantitative characteristics, and seasonal dynamics of phytoplankton in the Busse Lagoon, Sakhalin Island, have been studied based on data of the phytoplankton surveys in 2014–2015. A total of 306 species and intraspecific taxa of microalgae have been identified. The average monthly abundance of phytoplankton in this period varied from 14 790 to 105 190 cells/L; the biomass varied from 42.25 to 553.11 mg/m3. The average annual abundance of phytoplankton was 46 080 cells/L; the biomass was 176.13 mg/m3. Diatoms and dinophytes dominated in biomass throughout the annual cycle. Their seasonal dynamics was characterized by two peaks of abundance that coincided in time with the biomass peaks: in the spring (May) and summer (September). The spring peak was formed by the abundant proliferation of Rhizosolenia setigera; the summer peak was composed of Prorocentrum micans. A comparison of our observation results with the published data revealed some changes in the seasonal dynamics of species composition, quantitative parameters, and the assemblage of dominant species.