Amin, BintalNirrachmi, Irvina2013-05-302013-05-302013-05-30wahyu sari yenihttp://repository.unri.ac.id:80/handle/123456789/3508survey on the oil content and diatom abundance has been conducted in the coastal water adjacent to oil industry activities. Two locations (Sungai Pakning and Selat Lalang) with three stations each were selected for the sampling. Oil content analysis and identification of diatom were carried out in Marine Chemistry Laboratory and Marine Biology Laboratory, Fisheries Faculty, University of Riau. The result showed that all water quality parameters measured in the present study were still in the range of tolerable levels for the survival of marine organisms. The mean oil content varies from 0.35 to 0.37ppm and diatom abundance ranged from 1433,33 – 1566,67cel/l consisted of 10 species in Sungai Pakning whilst in Selat Lalang ranged from 0.34 to 0.54 ppm and diatom 1813,33 – 2200,00 cel/L with 7 spesies. Oil contents found at the stations closed to oil industry were generally higher than that at the station far from any oil-related activities. In both locations, the oil contens were measured to be higher during high tide compared to low tide. The increase of oil content in the waters was followed by the decrease in diatom abundance. Simple linear regression analyses indicates negative correlation between oil content and diatom abundance (Y = 2620 – 3000X; r = 0,4878and Y = 3546 – 5885X; r = 0,9110 in Sungai Pakning and Y = 3098 – 1947X; r = 0,7113 and Y = 2775 – 2152X; r = 0,3347 in Selat Lalang respectively) during high and low tide.enPollutionhydrocarbondiatomoil industryUR e-Research