Analysis of water condition based on suspended sediment distribution and phytoplankton abundance in Lasolo Bay, Southeast Sulawesi Province

Abstract

Abstract Lasolo Bay is a part of water in North Konawe Regency that connects the Lasolo River and sea waters. Several activities from Nickel mining activities that have been carried out around the bay have caused the physical condition of Lasolo Bay to change, namely an increase in turbidity and Total Suspended Solids (TSS) in marine waters. TSS and phytoplankton are among the indicators for determining the level of productivity of water. The purpose of this study was to determine the effect of TSS, nitrate and phosphate on phytoplankton abundance as an indicator of the level of aquatic productivity. The study was conducted in August 2021. Determination of sampling location based on purposive sampling method at 9 stations based on three layers of light penetration depth of 100%, 50% and 25% of surface light intensity. TSS analysis using gravimetric methods and phytoplankton abundance analysis using the Sedgwick Rafter Counting Chamber tool at the Biological Laboratory of FMIPA University of Halu Oleo. The results showed that TSS concentrations ranged from 160–390 mg/l and phytoplankton abundances at each station ranged from 1208–3040 cells/l. Increased TSS concentrations affect phytoplankton abundance. In general, high TSS values were at stations close to the mouth of the Lasolo river and high phytoplankton abundances were in the central part of Lasolo Bay. The abundance of phytoplankton in the waters of Lasolo Bay falls into the moderate category.