Phytoplankton community structure in Kemanyungan-Linduk estuaries and adjacent water of Banten Bay, West Java, Indonesia

The estuary in Banten Bay has a lot of pressures from the surrounding area due to industries and settlements. This condition could trigger pollution and sedimentation to the estuary and coastal waters. This study aims to reveal ecological status based on phytoplankton community structure in Kemayungan-Linduk waters of Banten Bay. Samples were collected at 6 stations from February to April 2021. The data included environmental factors, phytoplankton composition and abundance, species richness index, diversity index, and evenness index. Water quality parameters showed a high variability during the observation. Higher turbidity was recorded in Kemanyngan estuary. Phytoplankton consisted of Bacillariophyceae, Chlorophyceae, Cyanophyceae, Dictyochophyceae, Dinophyceae, Euglenophyceae, and Zygnematophyceae, with Bacillariophyceae as a dominant group contributing 54.1% out of 100% of total abundance. Higher percentage of Bacillariophyceae in coastal waters was related to salinity, potential of hydrogen (pH), and transparency. Higher percentage of Chlorophyceae and Euglenophyceae in Kemanyungan estuary was related to total suspended solid (TSS), turbidity, and nitrate (N-NO3). Higher percentage of Cyanophyceae and Dinophyceae in Linduk estuary was related to total phosphorus (TP) and dissolved oxygen (DO) respectively. Phytoplankton abundance (1330 to 13831 Individual L-1), number of species (14 to 27), diversity index (0.82 to 3.12), species richness index (1.52 to 4.39), and evenness index (0.30 to 0.91), showed a large heterogeneity across the sampling sites and sampling time. The lowest index diversity, species richness index and evenness were recorded in coastal water around Kemanyungan estuary. Based on the phytoplankton diversity index, it is shown that ecological status in the study area was moderate stress