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Anadara granosa is a species of the class bivalve commonly found on the east coast of South Sumatra as a fishery commodity. This species has not been widely studied as a source of new bioactive compounds that have antioxidant abilities. This study aims to analyze the antioxidant ability of A. granosa against DPPH radicals and its phytochemical profile qualitatively. Samples were taken at the fishing port of Sungsang Village, South Sumatra, Indonesia. Furthermore, the samples were extracted using ethanol as a solvent and tested for antioxidants against DPPH radicals, total phenol analysis, and preliminary phytochemical test. Based on the antioxidant test results, the IC50 value of the ethanolic extract of A. granosa was 85 g/ml with ascorbic acid 2 g/ml as a comparison. Then, the ethanol extract contained a total of 10.7057 mgGAE/g phenol and the results of the phytochemical test contained bioactive compounds of alkaloids, steroids, flavonoids, saponins, and tannins. The ethanolic extract of A. granosa contained bioactive compounds, which were reported to have potent antioxidant activity. The results of this study were expected to be important information in the latest report of the antioxidant activity of A. granosa species and contributed to the development of marine natural products.

Estuari Sungai Musi merupakan perairan semi tertutup yang dipengaruhi oleh dinamika pasang surut sehingga hanya beberapa biota khas yang mampu bertahan hidup di kawasan ini. Penelitian ini bertujuan untuk memahami tingkat biodiversitas kelompok gastropoda dan krustasea yang hidup pada zona intertidal estuari Sungai Musi. Pengambilan sampel dilakukan pada Bulan November 2021 di 5 titik stasiun pengamatan dengan metode transek kuadrat. Pengukuran kualitas perairan dilakukan meliputi suhu, pH, oksigen terlarut, dan salinitas. Hasil penelitian menunjukkan bahwa komposisi individu total krustasea (52%) dan gastropoda (48%). Kelimpahan total tertinggi hingga terendah secara berurutan ditemukan pada stasiun 4, 5, 2, 1, dan 3. Nilai indeks keanekaragaman berkategori sedang dengan nilai 1.30 – 1.76 nilai indeks keseragaman berkisar 0.48 – 0.65, nilai indeks dominansi 0.19 – 0.30. Berdasarkan hasil PCA menunjukkan bahwa F1 terdiri dari stasiun S1, S2, S4, dan S5 dengan variabel utama suhu, salinitas, DO, pH, keanekaragaman, keseragaman, dan dominansi sedangkan F2 terdiri dari stasiun S3 dengan kelimpahan. Berdasarkan hasil penelitian ini, zona intertidal menjadi habitat yang baik untuk kedua kelompok namun lokasi habitatnya cukup berpengaruh terhadap sebarannya secara spasial.

This study reveals the distribution of Bacillariophyceae in estuarine-mangrove which is mainly influenced by the quality of the waters. The main component analysis approach between variables is critical in this study because it determines the environmental characteristics in each estuarine zone. Estuarine-mangrove environments have different physical-chemical dynamics compared to other types of waters, one of which is Musi Estuary, located on the coast of South Sumatra. The aquatic environment of the Musi Estuary is influenced by tidal fluctuations that bring nutrients from inland waters and mangrove litter. This condition is perfect for the phytoplankton habitat, which plays an essential role in the ecological processes of waters as primary producers. This study aims to examine the diversity of Bacillariophyceae phytoplankton in the mangrove estuary environment and its possible role in estuarine ecology. Data were collected at ten observation stations in July, including samples of phytoplankton and water physical-chemical data such as pH, dissolved oxygen, temperature, salinity, water brightness, current speed, nitrates, and phosphates. Quantitative measurement of phytoplankton was performed using an Olympus CX23 light microscope at 100X magnification, while data were analyzed using PCA and Bray-Curtis similarity analysis. Water environment conditions were measured in a stable range in each zone except for salinity and brightness. Furthermore, only Bacillariophyceae were observed in all observation zones dominated by the Skeletonema genus. It is a dominant presence, and its abundance determined its role as a significant primary producer in the estuary outer zone near the sea. This study implicitly revealed the existence of Skeletonema in influencing ecological processes in estuary mangrove waters.