Phytoplankton abundance and diversity in the Northern Banda Sea

Abstract

Although phytoplankton of the Banda Sea has been studied since 1970s, its information is still limited. In order to provide a better understanding of phytoplankton diversity, during the Expedition of Jala Citra 2 Banda 2022, phytoplankton sampling was done in the surface waters at five stations in the northern Banda Sea. The purpose of this study was to analyze the abundance and species composition of phytoplankton during the southeast monsoon season. Phytoplankton samples were taken at different mixing layers, kept them into sample bottle and were identify in the laboratory of Deep Sea Research Centre BRIN Ambon. Chemical and physical parameters were measured simultaneously. A total of 64 species of phytoplankton were found and they composed of diatom which the most diversified group with 48 species, followed by dinoflagellate with 16 species. Among diatoms, most dominant species were contributed by Thalassionema nitzschiodes (3640-1,266,573 cell/m3) and Thalassionema fraunfeldii (2800-288,570 cell/m3) followed by Chaetoceros sp and Skeletonema costatum. These dominant species composition were different from previous reports. Most of these species were found in a chain. For the dinoflagellates Ceratium longipes (280-5,231 cell/m3) dan Ceratium vulvur (280-1.960 cell/m3) were identified as the dominant species. The cell count of total phytoplankton varied from 280-1,266,573 cell/m3. Spesies diversity index was calculated using Shannon’s formula (H’) and dominance index (D) range from 1.089-2.552 and 0.117-0.418, respectively. Water temperature, salinity, pH and dissolved oxygen ranged from 26.7-29.5°C, 33-34 ppt, 7.85-8.14, and 5.57-7.03 mg/l, respectively.