Abstract The research of chlorophyll-a concentration conducted in June-July 2020 at Lake Teluk Petai Buluh Nipis village. A study aims to understand the concentration and throphic state Teluk Petai lake based on chlorophyll-a. There were 3 stations namely station 1 (inlet area), station 2 (in the middle of the lake) and station 3 (in the end of the lake). In each stations vertically there …