Indonesian Journal of Limnology

Strategies for Effective Plankton Management in Kijing Taiwanese (Anodonta woodiana, Lea): A Study on Stocking Density and Aquaculture Techniques

Rema Apria Ningrum — 2024-03-31

Understanding the dynamics of plankton in Kijing Taiwanese (Anodonta woodiana, Lea) cultivation is crucial for optimizing growth performance. This study aims to investigate the influence of stocking density and cultivation methods on the daily population dynamics of plankton in Kijing Taiwanese aquaculture. The experimental study tested different stocking densities in cultivation ponds, namely 5, 10, and 15 ind/m². Descriptive analysis was employed to interpret the data obtained. The results indicate that Kijing Taiwanese absorb approximately 40 liters/day of water with particle sizes ranging from 0.1 to 5.0 µm, achieving 100% and 99.5% filtration for particles > 4.0 µm and organic matter, respectively. Various class of plankton were identified in the cultivation ponds, including Bacillariophyceae, Chlorophyceae, Cyanophyceae, Dinophyceae, Euglenophyta, and Pyrophyta, with abundances ranging from 2000-68000 ind/cell. The study observed an increase in plankton abundance by approximately 700-2000 ind/cells daily. Water quality measurements revealed pH 7.4, temperature 29.4°C, TDS 92.3 mg/L, turbidity 9-45 NTU, BOD 1-3, DO 5 mg/L, and phosphate (PO₄) 0.3 mg/L. This research concludes that there is an influence between kijing stocking density and plankton population density. The interactions that occur are significantly different, because there are significant differences. The higher the distribution density of kijing, the lower the plankton population in the cultivation pond. Further research is recommended to explore the correlation between the abundance of specific plankton types and the growth of Kijing Taiwanese, considering nutrient elements.

Analysis of Microplastic Contamination in Teluk Kombal Estuary: Impact and Sources as the Reference for Further and Mitigation Strategies

Maya Aprilia — 2024-08-29

Microplastics (MPs) refer to plastic waste particles that measure less than 5 millimeters in size. Their presence is widespread in the environment, particularly in aquatic ecosystems, posing significant risks to coastal organisms and human health. This study aims to assess microplastic contamination in the Kombal bay estuary by conducting identification, abundance analysis, and characterization of microplastics. The method used was to characterize the area, sample extraction, observation and calculation of microplastic abundance, FTIR analysis, water quality testing, and data analysis. Originating from the Teluk Kombal river, this estuary is subjected to various human activities such as fishing, agriculture, and household waste disposal. Sampling was conducted at three representative locations: the estuary, agricultural areas, and residential areas within Teluk Kombal, North Lombok, West Nusa Tenggara, Indonesia. Samples were collected and filtered for identification using a microscope Olympus Culture Inverted, 4×100 magnification. The results revealed microplastic abundances ranging from 19.5±14.71 to 25±14.54 particles per liter in water, 9.25±8.54 to 10.75 ±9.53 particles per kilogram in sediment, and 10.25±13.28 to 10.5±10.28 particles per individual in Padina sp. across the three locations. Various types of microplastics, including fragments, films, pellets, and fibers, were identified, with dominant colors of yellow, blue, red, black, and green. The presence of microplastics in the Teluk Kombal estuary and river indicates that they have been contaminated with microplastics, which can cause serious problems for organisms inhabiting them. Therefore, further research is needed to investigate the impact of microplastics on organisms and ecosystems in the estuary.

Estimation of Pesticide Concentrations from Agricultural Land in Cangkringan and Pakem Subdistricts on Runoff in the Upper Opak Watershed

Andriana Eikintawarna — 2024-08-29

Agricultural activities in the Opak Watershed, especially in the upper part located in Sleman Regency, require special attention because they have the potential to have a negative impact on river water quality. The use of pesticides on agricultural land contributes to polluting river water through rainwater runoff. Runoff containing residual organophosphate pesticide residues will reduce river water quality. In order to prevent pesticide pollution in the Upper Opak Watershed (UOW) in a sustainable manner, effective management is needed. However, the lack of information regarding estimates of pesticide concentrations in runoff in the UOW could hamper the management process. Therefore, it is crucial to estimate pesticide concentrations from agricultural land in the Cangkringan and Pakem Subdistricts contained in runoff in the UOW. Estimation of pesticide concentrations in runoff can be done by conducting hydrological modeling. The Soil Conservation Service-Curve Number (SCS-CN) model is the simplest compared to other models, but this model needs to be combined with the Predicted Environmental Concentrations (PEC) model to be able to estimate pesticide concentrations contained in runoff in the UOW. The research results show that the Cangkringan Subdistrict is the larger contributor to the concentration of organophosphate pesticides in the runoff of the UOW. The runoff contains three types of active pesticide substances, with the highest concentration in the two subdistricts being the active substance Diazinon. Active pesticide substances from rice fields in Pakem Subdistrict did not contribute too much to the pesticide pollution on the UOW runoff. Most of the pesticide concentrations in the UOW runoff came from agricultural land.