The water quality assessment and biodiversity of phytoplankton in Phayao Lake, Phayao Province, Thailand

Abstract

The goals of this evaluation of Phayao Lake were to evaluate the physical, chemical, and biological water quality, to determine the phytoplankton biodiversity, and to examine the relationship between biodiversity and water quality. Seven stations gathered samples for six months, from September 2020 to February 2021. Twice a month, samples were collected from each location. The results identified eight divisions, fifty-nine genera, and eighty-nine species. The most prevalent division of phytoplankton was Chlorophyta (45%), composed of 40 species. Coelomoron sp. was the most dominant species, with 732 ± 252 individuals L-1. The ranges for the Shannon – Wiener index, the evenness index, the richness index, and the index of similarity were 0.210 to 3.101, 0.151 to 0.985, 0.481 to 6.487, and 40.00 to 76.11, respectively. Based on the relationship between water quality variables and phytoplankton and utilizing statistical data analyzed using canonical correspondence analysis, phytoplankton was categorized into seven types, each of which was linked to an increase in dissolved oxygen levels. Although community-use water was classed as having medium to low nutrient levels, the average water quality in terms of dissolved oxygen (DO), biological oxygen demand (BOD), conductivity, nitrate concentrations, and phosphorus was classified as having medium to high nutrient levels. Because aquatic organisms use the area surrounding Phayao Lake as a nursery and breeding site, it has been. It will continue to be an important source of food for the community. Aquatic animals use the area surrounding Phayao Lake as a nursery and breeding ground; hence, this area is and will continue to be an important food source for the local community. Long-term monitoring determines the annual phytoplankton succession and identifies the progression of anomalous events, as recommended by the policy recommendations.