Abstract:
This research was conducted from September to October 2012 and aims to understand the relationship between nitrate and phosphate content with phytoplankton abundance. There were three stations. Sample were taken 3 times, once/week and they were analyzed in the aquatic ecology and environmental management Laboratory of the Fisheries and Marine Science Faculty, Riau University.
Result shown that the phytoplankton obtained were consisted of 27 genus, they were Cyanophyceae (5 genus), Chlorophyceae (13 genus), Bacillariophyceae (8 genus) and Euglenophyceae (1 genus). The average of phytoplankton abundance was around 20520 - 10920 cells/l, diversity index (H’) around 2,23 – 2,39, dominancy index (C) around 0,22 – 0,28 and diversity index (E) around 0,59 – 0,63. The result of water guality parameters respectively were: temperature : 29.30 – 29.500C, dissolved Oxygen: 2.61 – 2.93 mg/l, pH : 6, turbidity : 2 – 3.3 NTU, CO2 : 7.20 – 11.20 mg/l, Nitrate : 0,08 – 0,17 mg/l and phosphate : 0.10 – 0.13 mg/l. The results of water guality parameters is still supported. The trophic status of Singkarak Lake based on phytoplankton abundance was mesotrophic. The relationship of the abundance of phytoplankton with nutrient showed that nitrate and phosphate influenced phytoplankton abundance but not all station locations is influenced by nitrate and phosphate.
