Environmental Science
M. N. Hidayat; R. Wafdan; M. Ramli; Z. A. Muchlisin; S. Rizal
Abstract
BACKGROUND AND OBJECTIVES: This study aimed to investigate the long-term relationship between chlorophyll-a, sea surface temperature, and sea surface salinity monthly from January 2015 to December 2021. It was carried out in the Northern Bay of Bengal, which experiences extreme monsoons, in the southwest ...
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BACKGROUND AND OBJECTIVES: This study aimed to investigate the long-term relationship between chlorophyll-a, sea surface temperature, and sea surface salinity monthly from January 2015 to December 2021. It was carried out in the Northern Bay of Bengal, which experiences extreme monsoons, in the southwest monsoon and northeast monsoon from June to September and November to February, respectively. Monsoon is the main cause of changes in chlorophyll-a, sea surface temperature and sea surface salinity.METHODS: The seasonal model was used to examine the relationship between these three parameters, which were obtained using the Copernicus Marine Environment Monitoring Service data. The seasonal model was used to observe periodic patterns and predict parameters based on their regularity. Meanwhile, Pearson’s correlation analysis was conducted to determine the relationship between chlorophyll-a, sea surface temperature and sea surface salinity.FINDINGS: This study found that the three parameters, namely chlorophyll-a, sea surface temperature, and sea surface salinity, follow the monsoon pattern, as shown in the seasonal model. The minimum value of chlorophyll-a occurred in February, March and April, while the maximum value of approximately 2 milligram per cubic meter occured at stations 1, 2, 3, 4, 5 and 7, but at 9 and 10, it increased to 12 - 14 mg/m3. This indicates that station positions are very sensitive to changes in chlorohophyll-a values. When the southwest monsoon occurred, it reached the maximum. Furthermore, the minimum sea surface temperature values occurred in January and at almost every station in the year. It was shown to be associated with the northeast monsoon, which causes winter. On the sea surface temperature graph, several peaks were observed in positive local extremes yearly at almost all stations. The maximum sea surface temperature occurred in May, June, and July, according to the shape of the graph, which peaked in the middle of the year. The sea surface salinity graph formed a peak and valley which occurred yearly in May or April, as well as September and October, respectively.CONCLUSION: Chlorophyll-a had 1 trough and 1 peak, with the sea surface temperature graph possessing only 1 peak, while the sea surface salinity graph had 1 peak and 1 trough, respectively. These graph patterns implied that chlorophyll-a first achieved a minimum value before reaching the máximum. The sea surface temperature graph had a maximum value in the middle of the year, while the minimum occurred at the beginning or end. Moreover, the sea surface salinity graph first reached the maximum value and then declined to the minimum. KEYWORDS: Coefficient of correlation; Copernicus Marine Environment Monitoring Service (CMEMS Data); Northern Bay of Bengal; Northeast monsoon; Seasonal model; Southwest monsoon.
Environmental Engineering
M.R. Maulana; S. Saiful; Z.A. Muchlisin
Abstract
BACKGROUND AND OBJECTIVE: The occurrence of plastic waste pollution in waters has become a major issue globally. One of the waters which tend to be polluted with plastic waste such as bags, food wrappers, and unused fishing nets, is the Krueng Aceh River, which is located in the center of Banda Aceh ...
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BACKGROUND AND OBJECTIVE: The occurrence of plastic waste pollution in waters has become a major issue globally. One of the waters which tend to be polluted with plastic waste such as bags, food wrappers, and unused fishing nets, is the Krueng Aceh River, which is located in the center of Banda Aceh city, Indonesia. Microplastics in the rivers potentially contaminate the fish through the food chains, and are then transferred to humans once consumed. The two species of fish that are frequently caught by fishermen in the Krueng Aceh River and consumed by the local people are mullet Mugil cephalus and bagok catfish Hexanematichthys sagor. Both have the potential of being contaminated with microplastics that enter the river. Therefore, this study aims to analyze the status of microplastic pollution in mullet M. cephalus and bagok catfish H. sagor harvested downstream of the Krueng Aceh River, Banda Aceh, Indonesia.METHODS: The fish samples were caught in three locations, namely in the river estuary, residential, and agricultural areas. A total of 50 mullets and 46 bagok catfish were employed for analysis. Microplastics were analyzed in the digestive tract using a microscope, while waste in the carcass was detected using the fourier transform infrared analysis.FINDINGS: In mullet, the highest number of microplastic particles were found in fish samples caught in river estuary (16 particles/fish on average), followed by the sample from residential areas (10 particles/fish on average). Meanwhile, the lowest abundance of microplastic was recorded in sample near agriculture areas (5 particles/gram body weight). In bagok catfish, microplastic abundance in samples from the river estuary and residential areas was almost the same, and it ranged from 7-8 particles/fish. The lowest particle number was in bagok catfish caught in the region near agricultural areas. This study indicated fiber as the most dominant microplastic in the two fish species at all sampling locations. It also had three colors in the alimentary tract of mullet and bagok catfish, namely red, blue, and black, which was predominant. The fourier transform infrared spectrum showed several wavenumber peaks signifying alkane compounds’ presence, which are microplastic characteristics. Based on the peak values, the presence of two polymer types was suspected, namely polyethylene, and polypropylene.CONCLUSION: Fiber and film microplastics were found in the digestive tract of mullet and bagok catfish, where the number of particles was most abundant in the mullet. The fourier transform infrared test was also detected the presence of microplastic pollutants in both species. This indicates that mullet and bagok catfish in Krueng Aceh River have been contaminated by microplastics and are not safe for consumption.
Environmental Science
M. Ikhwan; R. Wafdan; Y. Haditiar; M. Ramli; Z. A. Muchlisin; S. Rizal
Abstract
BACKGROUND AND OBJECTIVES: El Niño - Southern Oscillation is known to affect the marine and terrestrial environment in Southeast Asia, Australia, northern South America, and southern Africa. There has been much research showing that the effects of El Niño - Southern Oscillation are extensive. ...
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BACKGROUND AND OBJECTIVES: El Niño - Southern Oscillation is known to affect the marine and terrestrial environment in Southeast Asia, Australia, northern South America, and southern Africa. There has been much research showing that the effects of El Niño - Southern Oscillation are extensive. In this study, a simulation of an El Niño event is carried out, which is ideal in the vertical layer of the Pacific Ocean (0-250 meters). The fast Fourier transform is used to process the vertical modeling data so that the results can accurately represent El Niño.METHODS: A non-hydrostatic 3-dimensional numerical model is used in this research. To separate the signal produced and obtain the quantitative difference of each sea layer, the simulation results are analyzed using the fast Fourier transform. Winds blow from the west to the east of the area in perfect El Niño weather, with a reasonably high wind zone near the equator (forming a cosine). Open fields can be found on the north and south sides, while closed fields can be found on the west and east sides. Density is uniform up to a depth of 100 meters, then uniformly increases by 1 kilogram per cubic meter from 100 to 250 meters. FINDINGS: The results of the model simulation show that one month later (on the 37th day), the current from the west has approached the domain's east side, forming a complete coastal Kelvin wave. The shape of coastal Kelvin waves in the eastern area follows a trend that is similar to the OSCAR Sea Surface Velocity plot data obtained from ERDDAP in the Pacific Ocean in October 2015. In this period, the density at a depth of 0-100 meters is the same, while the density at the depth layer underneath is different. CONCLUSION: Strong winds could mix water masses up to a depth of 100 meters, implying that during an ideal El Niño, the stratification of the water column is influenced by strong winds. The eastern domain has the highest sea level amplitude, resulting in perfect mixing up to a depth of 100 m, while wind effect is negligible in the lower layers. The first layer (0-50 m) and the second layer (50-100 m) have the same density and occur along the equator, according to FFT. The density is different and much greater in the third layer (100-150 m).