Relationship between phytoplankton and water qualities at Ao Nok, Chanthaburi Province

Abstract

The purpose of this study was to investigate the relationship between phytoplankton and water qualities at Ao Nok, Chanthaburi Province from December 2012 to August 2013. Phytoplankton and water qualities were collected every three months in 7 stations. The result of this study illustrated that 165 species of phytoplankton in 4 divisions had been found composed of 9 genera of Division Cyanophyta, 37 genera of Division Chlorophyta, 3 genera of Division Pyrrophyta and 116 genera of Division Chromophyta. Phytoplankton in Class Bacillariophyceae was the dominant species. The dominant genera of this study were Bacteriastrum sp., Ceratium sp., Chaetoceros sp., Coscinodiscus sp., Nitzschia sp., Odontella sp., Pleurosigma sp., Rhizosolenia sp., Surirella sp., Thalassionema sp., and Thalassiothrix sp. Phytoplankton division changed by season. Average phytoplankton density was 4.04x10⁴ unit/l. The high density of phytoplankton had been found the station near the river mouth in winter because of the high concentration of total ammonia and orthophosphate.