Abundance, composition and distribution of phytoplankton in West Central Sulu Sea

Abstract

A total of 28 stations were sampled for abundance, composition and distribution of phytoplankton in the West Central Sulu Sea. The samples were taken from 15-30 April 2007. Samples were collected by filtering 50L of surface water through a 20 pm mesh plankton net. A total of 96 phytoplankton genera were identified and were grouped into four major taxa. The overall mean density was 444.6 cells/L. Diatoms were the most abundant, with the mean density of 213.5 cells/L. The most abundant diatom genus was Chaetoceros. Blue-green algae showed the second-highest mean density of 127.6 cells/L. Trichodesmium was the most abundant genus among the two blue-green algae identified. Trichodesmium was also the most abundant genus, comprising 28.1% of all phytoplankton identified. Dinoflagellates and silicoflagellates were ranked third and fourth among the four major taxa with 77.5 cells/L and 28 cells/L, respectively. Protoperidinium was the most abundant dinoflagellate, while Amphorella was the most abundant silicoflagellate. They made up 6.2% and 1.2 % of all phytoplankton identified, respectively. The stations located along the coast of Palawan and near the Tubattaha Reef Marine National Park showed the highest phytoplankton concentrations.