Spatial distribution of phytoplankton in Lasolo Bay of Southeast Sulawesi province, Indonesia

This study aimed to analyze the distribution of phytoplankton abundance and its relationship with water quality in Lasolo Bay waters. The study was conducted during the West season 2020. The sample consisted of 9 stations located near the mouth of the Lasolo River (station A), coastal waters (station B) and the center part of Lasolo Bay (station C). Phytoplankton sampling was using plankton nets with 25 µm mesh size. Identification of phytoplankton used microscope and the abundance calculation by using Sedgwick Rafter Counting Cell. The results showed that there are 23 phytoplankton genera from 5 classes found, namely 12 genera of Bacillariophycea class, 5 genera of Dinophyceae class, 3 genera of Chlorophyceae class, 2 genera of Cyanophyceae class and 1 genera of Coscinodiscophyceae class. By abundance, phytoplankton compositions of the class Bacillariophyceae predominate with a percentage of 57%. The type of phytoplankton that has the highest abundance is Nitzschia sp. of 2,407 cells/l and the lowest abundance of Amphidium sp. of 1,368 cells/l. Phytoplankton abundance at station A is 41,093 cells/l, station B is 14,234 cells/l and station C is 14,735 cells/l. The distribution of phytoplankton abundance is also influenced by physical and chemical factors such as turbidity, TSS, Nitrate, and Phosphate.