Indications of Limnology Trophic State Water Resources Management in the Water Body of Lake Santa Maria Tasi Tolu Dili, Timor-Leste

Eutrophication of freshwater and saltwater is a natural phenomenon that is currently exacerbated by human activities, resulting in increased nutrient concentrations, especially nitrogen and phosphorus. This study reveals that observations indicate a decline in biodiversity in Lake Santa Maria Tasi Tolu Dili, which is in line with the deterioration of ecological conditions and the destruction of its habitat. This study aims to explore indicators of eutrophication in Lake Santa Maria, specifically focusing on human activities and their impacts on environmental pollution, eutrophication, and algal blooms in freshwater lakes, saltwater lakes, and rivers. The main objective of this study is to explain the mechanism of eutrophication and identify factors contributing to algal blooms in Lake Santa Maria waters. In addition, this study will discuss the relationship between eutrophication and algal blooms, as well as the consequences of environmental pollution in lake water. Qualitative methodology, as described by Oranga and Matere (2023), involves an in-depth analysis of specific cases within a broader category of phenomena, which are generally referred to as case studies. While this approach may not yield universally applicable insights, it can be a valuable tool in the early stages of research, facilitating the development of hypotheses that can be rigorously tested with a larger sample size. As highlighted by Hunter et al. (2019), this research adopted an exploratory approach to data collection, which included direct field data collection or primary data generation to gain a deeper understanding of a particular subject, phenomenon, or issue. The findings of this investigation reveal that the eutrophication of Lake Santa Maria is influenced by a variety of factors. Lake Santa Maria is predominantly characterized by the presence of green, red, brown, and golden algae, as well as various macrophytes. These algal species create floating colonies within the lake, while others are situated along the shores, coexisting with macrophytes. They flourish within a temperature range of 25°C to 32°C and have demonstrated adaptability to a pH range of 7.12 to 7.43, along with salinity levels between 14‰ and 15‰. Notably, there is evidence of eutrophication occurring in the lake's waters. The cyanobacterial species identified include Anabaena, Oscillatoria, Nodularia, Nostoc, and Microcystis aeruginosa. The effects of eutrophication and drought on the lake's biotic community are profound, particularly due to elevated evaporation rates resulting from daily high temperatures and dry winds, which further exacerbate fish mortality alongside lake pollution. To avert further degradation of the lake's water quality, it is essential to implement clear regulations and provide comprehensive information to the surrounding community.