摘要：This study aims to determine (physico-chemical) parameters of water and also community structure of plankton surface in natural tourism Labuan Cermin Biduk-Biduk, Berau, Kalimanta n Timur. This study used Purposive Sampling method. Data obtained shows in plankton abundance, diversity index, evenness index and dominance index. The result of study showed that range of temperature between 24,04 o C -26,88 o C, range of salinity between 0.25 -0.87 o / oo which classified in freshwater-brackish water, range of power flow between 1.121-2.930 m/s which classified in moderate level, the average pH between 6,76-7,48 which classified in neutral level, range of TDS between 514-788 mg/L which classified in normal level, respectively. Plankton sample showed 27 classes including of 22 classes of phytoplankton with 57 genera and 5 classes of zooplankton with 10 genera. The highest total plankton abundances of 35917 ind/L is in Station A and the lowest total plankton abundances of 8330 ind/L is in Station F.
