Lake Batur’s water quality on Bali Island has significantly declined, leading to massive annual fish mortality rates. The suspected reason is the expansion of aquaculture using floating net cages (FNC) beyond their capacity. The study aims to assess the impact of FNC-based aquaculture on water quality and organic matter distribution, specifically total organic matter, TSS, and chlorophyll a. The result states that Lake Batur has exceeded its carrying capacity of 10,047 plots since 2018 and currently holds 18,768 plots as of 2022. Within the last five years (2018-2022), the FNC discharged 5,947 tons of organic waste into Lake Batur, containing 1,779 quintals of nitrogen and 430 quintals of phosphorus. Consequently, each liter of Lake Batur water accrues 7.29 mg of organic waste annually, including 2.18 mg of nitrogen and 0.53 mg of phosphorus. Organic waste in Lake Batur has led to a reduction in water transparency, an increase in total organic matter (TOM), a decrease in dissolved oxygen (DO), and an increase in chlorophyll-a (Chl-a) concentrations. Its changes serve as indicators of eutrophication and degradation of water quality. The distribution of organic matter across the euphotic zone did not correlate with FNC distribution, suggesting that FNC distribution no longer influences organic matter distribution. Environmental factors surrounding the SL have emerged as the primary driver of differences in organic matter distribution. It demonstrates the dissemination of organic matter in the euphotic zone of Lake Batur due to the constant discharge of effluent by the long-standing FNC, which has surpassed its maximum capacity.

Human activities in lake catchments and waterways have a considerable detrimental impact on lake ecosystems, including processes such as eutrophication and siltation. The study’s objective was to gain a deeper understanding of the impact of anthropogenic activities on water quality, pollutant diffusion in Lake Batur waters, and the level of eutrophication. Water samples from nine sampling locations (SLs) in Lake Batur, Indonesia, were collected and examined for physical, chemical, and biological properties. The study revealed that Lake Batur receives a considerable quantity of anthropogenic waste on an annual basis, including 14,776 tons of organic matter (COD), 1,486 tons of total nitrogen (TN), and 461 tons of total phosphorus. The primary source of these effluents was autochthonous effluents from FNC operations, which constituted 74.4% of the COD, 86.6% of the TN, and 85.6% of the TP. The distribution of effluents from community activities across the ECW, WCW, and MLW resulted in variability in the concentrations of total suspended solids (TSS), nutrients, chlorophyll-a (Chl-a), chemical oxygen demand (COD), total nitrogen (TN), total phosphorus (TP), and fertility levels in the nine LS. The Chl-a/COD ratio indicated that SL 1, situated in the ECW, exhibited the highest fertility, whereas SL 5, located in the MLW, demonstrated the lowest. The fertility level was constrained by phosphorus, as evidenced by a TP/TN ratio exceeding 12 in eight SLs. The Trophic Status Index (TSI) was calculated using Carlton’s formula, and the results indicated that, with the exception of SL 2, which was categorized as mesotrophic, the remaining eight SLs were eutrophic. Given that the Trophic Status Index (TSI) (Chl-a) is greater than the TSI (TP), it can be reasonably concluded that phosphorus is the limiting factor for algal development in seven of the nine SLs. The TSI (Chl-a) values for some SLs (SLs 2-4) were observed to be lower than the TSI (SD) values, indicating that non-algal particles may have exerted a greater influence on lake water clarity.

The research conducted in Sumedang Regency highlights population growth, land use change, and the role of GIS, as well as the need for in-depth research for the development of more precise and effective agricultural policies. The aim of this study is to analyze food carrying capacity in Sumedang Regency in the face of rapid population growth and land use change; and to determine the impact of land use change on the availability of agricultural land and food carrying capacity in Sumedang Regency. Secondary data sources are used in this research. The research method is quantitative descriptive analysis. Limitations of the study include a focus on Sumedang Regency, dependence on available data, analysis of food carrying capacity with an emphasis on land use change, the use of GIS for spatial analysis, and the application of land optimization methods to selected sites. The analysis results indicate a food deficit in Sumedang Regency due to rapid population growth and land use change, requiring strategies to increase agricultural productivity and food availability policies. Land use change, especially conversion to non-agricultural uses, has a significant impact on the availability of agricultural land, resulting in food deficits and dependence on supplies from other areas, emphasizing the need for wise land planning to maintain a balance between agriculture and the environment. Keywords: Food Carrying Capacity, GIS Analysis, Sumedang Regency.