Wyniki wyszukiwania - Biblioteka Nauki

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Catch Comparison and Rate of Floating Liftnet at Different Time of Hauling in Pangandaran, West Java, Indonesia

100%

Apriliani I. M. , Dwipayana M. F. , Sunarto S. , Rostini I.

World News of Natural Sciences

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2019

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tom 22

168-173

EN

Pangandaran fishermen use various types of fishing gear to catch fish, one of which is a liftnet. Floating liftnet fishing in Pangandaran is usually carried out at night, especially during dark months so that fish and cructaceans can gather in the area, as such animals are attracted to light (positive phototactic properties). These animals are deemed pelagic as they live on the surface of the waters. The weight and number of catch by fishermen are different depending on the time of hauling. Based on this, it is necessary to conduct research on the effect of the time of hauling on the floating liftnet catch. Accordingly, the optimal hauling time for floating liftnet fishing in Pangandaran was after midnight into early morning (00.00-04.00) and the average total catch is 386.12 kg. The main catch is mostly jawla paste shrimp and squid shrimp with a catch rate of 92.9 kg / hour.

2

Diseases prevalence of Acropora corals: Study on Semak Daun Island, Seribu Islands, Jakarta

100%

Harahap S. A. , Fadhil F. , Sunarto S.

World News of Natural Sciences

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2021

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tom 34

113-126

EN

Coral reefs have undergone significant degradation as a result of the impact of human disturbance and natural factors on biodiversity and ecosystem function. The impacts ranged from an increase in the appearance of coral bleaching, coral disease, to coral death. Especially for coral disease, it is confirmed that it has contributed to the reduction of live coral cover and the productivity of coral reef ecosystems. The coral disease can be epidemic due to environmental pressures, both anthropogenic and natural, as well as infection from pathogenic microbes. Recently in several places, including Semak Daun Island, Seribu Islands-Jakarta, it was reported that the condition of coral reef cover had increased. However, a high percent of coral cover can increase disease prevalence and abundance. Acropora coral is a type of coral that is commonly found on Semak Daun Island. However, these corals are very susceptible to stress so that the threat of disease is high. So it is necessary to conduct a study that aims to determine the type and prevalence of diseases that disturb Acropora coral in Semak Daun Island, Seribu Islands, Jakarta. The field survey was carried out for coral observation using the line transect method at four stations. Coral disease identification refers to the Coral Disease Handbook and Underwater Cards for Assessing Coral Health. Observation objects, both coral species, and signs of disease were documented using underwater cameras. The study results indicate that 15 types of Acropora corals were dominated by A. humilis. Meanwhile, two groups of diseases were found, namely Tissue loss - Predation caused by the COTS and Drupella, while those from the Compromised Health group included RFA, SD, and Sponges.

3

Analysis of the Quality and Pollution Load Carrying Capacity of Point Source Pollutants due to Tofu Industry Waste in Garuda River, Sragen Using QUAL2Kw Modeling

100%

Rizky F. A. , Sunarto S. , Suryawan I. W. K. , Suhardono S.

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2024

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tom Vol. 25, iss. 9

311--327

EN

The Garuda River is one of the tributaries of Bengawan Solo in Sragen Regency which is suspected of experiencing a decline in water quality. This study aims to determine the quality and pollution load carrying capacity (PLCC) of the Garuda River to the source of pollutants, especially those caused by tofu industrial liquid waste. The research method used in this study is a quantitative method to analyze the status of river water quality using the pollution index (PI) method and the calculation of river PLCC using the QUAL2Kw model with 3 modeling scenarios. The analysis showed that the Garuda River was proven not to meet the class III quality standards because several parameters such as temperature, TSS, nitrite (NO2 -N), and total Coliform were above the set quality standards. Based on the calculation of the pollution index, it was found that the Garuda River was proven to be polluted with a lightly polluted quality status with a pollution score ranging from 1.49 to 2.91. Based on QUAL2Kw modeling, it was found that the PLCC of Garuda River for TSS parameters was 233.28–259.20 kg/day, BOD was 12.96–15.55 kg/day, and COD was 51.84–103.68 kg/day. One of the control efforts that can be carried out is reducing the pollutant burden on each source of pollution, especially point source pollutants from tofu industrial liquid waste.

4

The optimisation model for groundwater management in the unconfined aquifer using the Shuffled Complex Evolution algorithm

88%

Sulianto , Sunarto S. , Samin S. , Orfa L. E. , Darmawan A. A.

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tom no. 59

83--92

EN

Groundwater exploitation that exceeds its recharge capacity can have a negative impact on the hydrogeological environment. Optimal exploitation means maximising pumping discharge with the least reduction in the hydraulic head. In groundwater exploitation, the position of wells, number of wells, and the discharge of groundwater pumping greatly determine changes in hydraulic head and groundwater flow patterns in a given hydrological area. This article proposes an optimisation model which is expected to be useful for finding the optimal pumping discharge value from production wells in a hydrological area. This model is a combination of solving the Laplace equation for two-dimensional groundwater flow in unconfined aquifers and the optimum variable search method based on the Shuffled Complex Evolution (SCE-UA) algorithm. Laplace equation uses the finite difference method for the central difference rule of the Crank Nicolson scheme. The system of equations has been solved using the M-FILE code from MATLAB. This article is a preliminary study which aims to examine the stability level of the optimisation equation system. Testing using a hypothetical data set shows that the model can work effectively, accurately, and consistently in solving the case of maximising pumping discharge from production wells in a hydrological area with a certain hydraulic head limitation. Consequently, the system of equations can also be applied to the case of confined aquifers.