Quantity and Distribution of Plant Nutrients on Eutrophication in Bang Pra Reservoir, Chonburi Province

Abstract

                The main objectives of this study were to study the quantity and variation of plant nutrients in water bodies supplied to Bang Pra reservoir including the characteristics of distribution and variation of plant nutrients and phytoplankton in Bang Pra reservoir. This study was conducted during March 2001–February 2002.

                In the inflowing brooks, the quantity of nitrite and total ammonia were significantly different (p<0.01) both in each brook and in each month. It was demonstrated that the quantity of nitrate and orthophosphate were significantly different (p<0.01) in each month but not different in each brook (p>0.05).

                 In Bang Pra reservoir, the quantity of nitrite in each water sample was different (p<0.05) and the quantity of total ammonia was significantly different (p<0.01). When considering both quantity of nitrite and total ammonia in each month, it was shown that they were significantly different (p<0.01). Statistical analysis indicated the significant difference of othophosphate quantity (p<0.01) in each month but not in
each water sample station (p>0.05). Given these conditions, Bang Pra reservoir can be classified as a eutrophic lake.

                 High quantity of plant nutrients in Bang Pra reservoir was mainly found at water sample stations of water receiving areas located at the mouth of brooks. The biological analysis revealed that phytoplankton, which was mostly found in Bang Pra reservoir was Aulacoseira, in Division Chromophyta. Moreover, in June, November 2001, and January 2002, Aulacoseira was found in such large quantity compared to other months that these periods could be regarded as periods of phytoplankton bloom.