THE STRUCTURE COMMUNITY OF PLANKTONIC DIATOM WITH NITRATE AND PHOSPHATE CONCENTRATIONS IN SEI UNDAN ESTUARINE SUB DISTRICT OF RETEH DISTRICT OF INDRAGIRI HILIR

Abstract

Research on the structure community of planktonic diatom with nitrate andphosphate concentrations in sei undan estuarine sub district of Reteh district ofIndragiri Hilir was conducted on May 2013. The aims of this study was todetermine the community structure of planktonic diatom which includes index ofdiversity, index of dominan and index of uniformity and was to determine therelationship between the nitrate and phosphate consentration with the abundanceof diatom. Sample were taken at 4 station each station was divided into 3sampling points. The identification result of sampel obtained 7 species of centricdiatoms anda 1 species of pennate diatom. The highest abundance of diatom wasfound in station 2 (7.846,95 ind/L) and the lowest was found in station 4 (2.615,65ind/L). The highest individual abundance was shown by Nitzschia pungens andLeptocylindrus minimus. It was indicated that dominan species in the waters.Based on index of diversity, index of dominan and index of unifornity the areawas categorized as mesotrofic area.Keyword: Sei Undan Estuarine, Diatom, Structure Community, Nitrate & Phosphate