Species Diversity of Phytoplankton and Relationship with Water Quality at Coastal area of Laem Phak Bia: The King's Royally Initiated Laem Phak Bia Environmental Research and Development Project, Phetchaburi Province

A study on species diversity of phytoplankton and its relationship with the water qualities at the coastal area of Laem Phak Bia: The King's Royally Initiated Laem Phak Bia Environmental Research and Development Project, Phetchaburi Province was conducted during a rainy period (September, 2012) and summer period (March, 2013). The results showed that phytoplankton was found in 52 genera of 2 Divisions, 5 genera in Cyanophyta and 47 genera in Chromophyta. The dominant species belong to genus Coscinodiscus and Chaetoceros. Average water quality of seawater in the coastal area of Laem Phak Bia was still in good condition. The index of species diversity and evenness index of phytoplankton were 3.61 and 0.80, respectively. The observed indices related to phytoplankton exhibited significant positive correlations with the water temperature, dissolved oxygen, TKN, nitrate, orthophosphate and chlorophyll a content (P<0.01), whilst they showed significant negative correlations with the pH, salinity, ammonia, hydrogen sulfide and BOD of the water (P<0.01).