VERTICAL PROFILE OF DISSOLVED OXYGEN IN BANDAR KHAYANGAN RESERVOIR LEMBAH SARI SUB DISTRICT RUMBAI PESISIR DISTRICT PEKANBARU

Abstract

The research was conducted from July to August 2012 in Bandar Khayangan Lembah Sari Reservoir. This research aims to understand the vertical profile of dissolved oxygen in this reservoir. Water samples were collected from six station, namely station R.1 and R.2 in riverine zone, T.1 and T.2 in transition zone and L.1 and L.2 in lacustrine zone. In each station, there were three sampling sites namely: in the surface, 2 Secchi depth and in the bottom. Sample was done three time and sampling interval once week. Water quality parameters measured were dissolved oxygen, free carbon dioxide, transparancy, pH, temperature, depth, current, nitrate, phosphate, ammonia and phytoplankton abundance. The result shown dissolved oxygen range 2,40 - 6,83 mg/l, free carbon dioxide 5,33 - 9,32 mg/l, transparancy 47,00 - 55,83 cm, pH 5, temperature 31,0 - 31,7 oC, depth 1,20 - 5,00 m, current 2,61 - 3,06 cm/sec, nitrate 0,01 - 0,09 mg/l, phosphate 0,02 - 0,25 mg/l, ammonia 0,06 - 0,29 mg/l, phytoplankton abundance in the surface range 480 - 936 cells/l, and in the 2 Secchi depth 432 - 904 cells/l. The highest concentration of dissolved oxygen in the surface of riverine zone (6,83 mg/l) and the lowest concentration in lacustrine zone. Based on the vertical profile of dissolved oxygen, it can be concluded dissolved oxygen concentration in lacustrine zone has decreased rapidly due to floating cage activity than the other zones.