Tropical Marine Environmental Sciences

Toxicity of Cadmium (Cd) on Artemia salina

2024-04-07T14:30:01+00:00

Cd is a non-essential metal and a widespread micropollutant that has physiological effects on aquatic organisms. Cd heavy metal poisoning can be acutely caused by contamination at high doses, while chronic poisoning is generally caused by low levels of contamination and long exposure time. This research was conducted in June 2022 at the Marine Chemistry Laboratory Faculty of Fisheries and Marine, Universitas Riau, which aims to determine the value of LC₅₀ (Lethal Concentration) for 24 hours after being given a toxicant in the form of Cd and to determine the level of Cd toxicity in A. salina. The method used in this research is the experimental method with the experimental unit A. salina. The LC₅₀ of Cd on A. salina revealed 11.7109 mg/L. This concentration is capable of causing the death of 50% of the test animals. Furthermore, the water quality in the acute toxicity test, P0 (control), was classified as good to support the life of A. salina, while at P1 (3.13 mg/L) - P5 (50 mg/L), it was classified as polluted.

The Identification of Upwelling in the Occurrence of Tropical Cyclone Charlotte in the Waters of Southern Java (Case Study: March 17-28, 2022)

2024-04-07T14:29:28+00:00

Tropical cyclones are one of the meteorological phenomena that can have negative impacts on humans. These impacts can include heavy rainfall leading to floods and even storm surges. However, tropical cyclones can also have positive effects as they can trigger upwelling. Upwelling affects the fisheries aspect because in areas where upwelling occurs, sea surface temperatures are lower, and nutrients (such as phosphate and nitrate) are lifted from deeper layers of the ocean, which can affect the growth of phytoplankton. The objective of this research is to identify and analyze the upwelling phenomenon in the waters south of Java Island during the occurrence of Tropical Cyclone Charlotte. The data used in this research includes the intensity and movement direction of Tropical Cyclone Charlotte from the zoom.earth website and sea surface temperature, chlorophyll-a, mixed layer depth (MLD), and sea level anomaly data from the E.U. Copernicus Marine Service Information (CMEMS)-Global Monitoring and Forecasting Center during March 17-28, 2022. The results of this research indicate that upwelling was not identified during the period before or after the cyclone, as evidenced by sea surface temperatures between 28.5-29.5°C, chlorophyll-α concentration of <0.15 mg/m³, and a sea level rise of 0.1 m

Analysis of Upwelling Parameters when the El Nino Southern Oscillation (ENSO) Occurred in the Halmahera Sea

2024-04-07T14:28:14+00:00

Upwelling events that occur in the Halmahera Sea are influenced by the El Nino Southern Oscillation (ENSO). Upwelling can cause sea surface temperatures to be lower than normal, affecting the potential of fishery resources in the region. The purpose of this study was to determine the conditions of sea surface temperature, chlorophyll-a content, salinity, and upwelling conditions when viewed from the parameters of chlorophyll-α content and sea surface temperature when El Nino was strong, El Nino was weak, La Nina was strong, and La Nina weak and in normal conditions in the Halmahera Sea region. The data used in this study include the Oceanic Nino Index, sea surface temperature, salinity, and chlorophyll-α content during the 2010–2019 period. A quantitative descriptive research type is used by filtering ENSO data to determine when ENSO occurred, then visualizing the data in each parameter and analyzing it. The results of this study show that upwelling is known to occur in the northern to western parts of the Halmahera Sea. When the El Nino phase is vital, the upwelling parameter changes, the sea surface temperature decreases to 27.1⁰C, the chlorophyll-α content increases to 0.70 mg/m³ compared to the normal phase, and the upwelling intensity changes

Macrozoobenthos Community Structure at Teluk Marunggai Beach, Nagari Sungai Nyalo, Pesisir Selatan District, West Sumatera Province

2024-04-08T04:22:33+00:00

Teluk Marunggai Beach, Nagari Sungai Nyalo, is one of the new tourist areas in Pesisir Selatan Regency which, over time, will begin to be in demand by tourists, which will have an impact on the life of the biota on the beach, one of which is macrozoobenthos. This research was conducted in March 2023 in the Intertidal Zone of Teluk Marunggai Beach, Sungai Nyalo Village, Koto Ampek Tarusan District, Pesisir Selatan Regency, West Sumatra Province. The purpose of this study was to determine the type and abundance of macrozoobenthos species in the coastal waters of Marunggai Bay and to determine the diversity, uniformity, dominance and distribution patterns of macrozoobenthos in the coastal waters of Marunggai Bay. The research method used is the survey method, where the sampling using the quadrant transect method is carried out at three stations. The research results found 40 species of macrozoobenthos. The most common species found at all stations were Turbo cinereus from the Turbinidae family and the Gastropod class. The macrozoobenthos abundance values obtained ranged from 6.44–6.67 ind/m². Species diversity index values ranged from 3.06–3.52, namely high. Uniformity index values ranged from 3.02 to 3.14, high uniformity, dominance index values ranged from 0.10 to 0.15; no species dominated, and the value of the distribution pattern ranged from 2.959 to 2.962 with a group distribution pattern

Catch Composition and Selectivity Drift Gillnet in Pambang Pesisir Village Bantan Subdistrict Bengkalis Regency

2023-06-09T06:53:29+00:00

Gill nets are placed perpendicular to the water to block the swimming direction of the fish. Fish are caught by being entangled in the meshes or entangled (spun) in the body of the net. This research was conducted in Pambang Pesisir Village, Bantan District, Bengkalis Regency, to know the composition of the catch and the selectivity of drift gill nets, comparing the composition of the number, type, weight, and size of the catch from different mesh sizes, and knowing how to catch fish (entangled, gilled, snagged, wedged) on the same mesh used. This research was carried out in December 2020 using the experimental fishing method, which is a research method that uses samples of research objects caught on fishing gear for observation. The research results of drift gill nets are species-selective fishing gear. Moreover, drift gill nets with a mesh size of 7.62 cm are more selective than nets of 5.72 cm because they have a catch ratio value closer to 1 and catch more large fish (worth catching). How to catch fish with a mesh size of 5.72 cm, many fish were caught by snagged; namely, 65 fish (30%), wedged 61 fish (28%), gilled 59 fish (27%), and 33 fish entangled (15%). Meanwhile, for the mesh size of 7.62 cm, 30 fish (31%) were caught wedged, 27 fish (29%) snagged, 27 fish (29%) gilled, and ten fish entangled (11%).