Abstract

Freshwater systems are vital in the control of biogeochemical cycles, biodiversity, and deliver valuable ecosystem services. Some of the most significant processes, which support these ecosystems, include benthic-pelagic nutrient interactions and air-water gaseous exchange. The processes are important in the nutrient availability, primary productivity, and greenhouse gases. The research will measure the effects of anthropogenic processes, such as agricultural runoff and industrial pollution, in a tropical freshwater ecosystem on these coupled processes. Field sampling, laboratory, and statistical methods are used to estimate the seasonal nutrient fluxes, gaseous exchange rates, and the association between anthropogenic stress and ecosystem functioning. The findings indicate that there are considerable seasonal differences in physicochemical characteristics, nutrient levels, and gaseous exchange. In particular, the nutrient fluxes were the most intense during the monsoon season: nitrogen flux 43.9 mg m²/day and phosphorus flux 15.9 mg m²/day. The CO₂ flux was higher in the monsoon of 272.6 mg m²/day compared to the winter of 118.5 mg m²/day, and the methane flux varied between 8.1 and 22.8 mg m ²/day. Statistical results indicated that there were strong relationships among biochemical oxygen demand (BOD), chemical oxygen demand (COD), and nutrient fluxes that supported the effects of nutrient loading by human activities on the microbial activity and greenhouse gas emissions. The study finds that the anthropogenic effects are greatly contributing to the cycling of nutrients, greenhouse gases, and the stress of the ecosystem, especially when there is a high level of nutrient loading. The research should be extended to long-term monitoring and sensor integration in real-time to enhance ecosystem management and sustainability in the future.

Keywords: Benthic-pelagic coupling, Nutrient flux, Air-water gas exchange, Anthropogenic impact, Greenhouse gas emissions, Eutrophication, Freshwater ecosystems