Phytoplankton is one of the parameters used to determine trophic state. The purpose of this study was to determine the trophic status of water based on phytoplankton in Rantau Panjang lake. This research was conducted in July-August 2024. Sampling was carried out at three stations, namely station 1 in the floating board cage area, station 2 inlet, and station 3 area affected by oil palm plantat…