Diniya, Atika2013-06-262013-06-262013-06-26sumarnihttp://repository.unri.ac.id:80/handle/123456789/3907The research was conducted in November 2012 in Bagan Siapiapi dan Bengkalis waters area, Riau Province. The research was aimed to find out the comparison of diversity and abundance diatom and shown the waters fecundity. Each location was divided into four stations, included Malacca Strait, fishing ground, estuary and settlement area. The study found 16 species of Centrales diatoms and 4 species of Pennales diatoms. The highest species total abundance among two location was at station 3, i.e. 50.522,752 sel/L, and the lowest was at station 7, i.e. 11.006,7424 sel/L. The highest individual abundance was shown by R. alata forma gracillma and Thallasiosira gravida. Bagan Siapiapi waters area was at the normal condition, it was indicated by no species was dominating the waters, so do Bengkalis. However, based on the results the Bagan Siapiapi’s was at middle level of contamination and Bengkalis’s was at low level of contamination.otherComparisonAbundanceThallasiosirastudent Paper Post Degree