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All Journal ASEAN Journal on Science and Technology for Development
A'an Johan Wahyudi
Research Center for Oceanography, Indonesian Institute of Sciences, Pasir Putih 1, Ancol Timur, Jakarta 14430, Indonesia
Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Computer Science & IT Mathematics

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Stable Carbon Isotope Signature of Particulate Organic Matter in the Southwestern Sumatran Waters of the Eastern Indian Ocean A'an Johan Wahyudi; Afdal Afdal; Hanny Meirinawati
ASEAN Journal on Science and Technology for Development Vol. 36 No. 2 (2019): Across the Archipelago
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1418.946 KB) | DOI: 10.29037/ajstd.555

Abstract

The Southwestern Sumatran Waters of the Eastern Indian Ocean are known to be affected by the South Java Current and the South Equatorial Counter Current. Many studies have been carried out in relation to upwelling and the Indonesian Through Flow. However, there has been no systematic study into the properties of the particulate organic matter in the Southwestern Sumatran Waters. Therefore, the organic matter in these waters in terms of its origin is unknown. As part of the Widya Nusantara Expedition 2015 research cruise, this study aimed to examine the stable isotope ?13C signature of particulate organic matter (POM), especially with regards to the origins of the organic matter. The stable isotope ?13C is complemented by other variables such as chlorophyll-a, particulate organic carbon (POC), and nutrients (phosphate, silicate, ammonium and nitrate). The POC tends to be depth-dependent. The values of ?13C are ?23.56, ?24.30 and ?24.06‰ for 5, 100 and 300 m depths, respectively. We found that POM tended to be isotopically lighter with increasing POC and chl-a, especially in the surface water, potentially due to the preferential lighter carbon isotope for metabolism by the primary producer. The origin of POM in the Southwestern Sumatran waters is marine end-member in the surface (up to 100 m depth) and mixed compositions at the surface of twilight zone (100–300 m depth). The next layer, i.e. twilight zone (more than 300 m depth), is terrigenous end-member. The surface POM of SSW, as shown in 5 m depth, is not freshly produced and tends to be either autochthonous or allochthonous.
Water Quality Assessment and Monitoring of Closed Rearing System of the Sea Cucumber Holothuria scabra Hanny Meirinawati; Hanif Budi Prayitno; Lisa Fajar Indriana; Muhammad Firdaus; A'an Johan Wahyudi
ASEAN Journal on Science and Technology for Development Vol. 37 No. 2 (2020): The Perennial Quest
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29037/ajstd.624

Abstract

Sea cucumbers are an essential fishery resource. Therefore, effective aquaculture methods should be developed to achieve their optimal production. Sea cucumbers are susceptible to various environmental factors, one of which is water quality. Monitoring water quality based on physical and chemical parameters should be useful to the rearing system in aquaculture. In practical use, farmers usually monitor only temperature, salinity, and pH, neglecting the essential role of chemical parameters. This review focuses on and urges the monitoring of physical and chemical parameters. We explored the water quality parameters that may be crucial to the sea cucumber rearing system, including temperature, salinity, pH, dissolved oxygen, ammonia, turbidity, particulate organic matter, total nitrogen, nitrate, nitrite, ammonium, silicate, and phosphate. Furthermore, this paper presents a practical way to monitor the aquaculture or rearing system of sea cucumbers. It is suggested that temperature and salinity are the crucial physical parameters, while the essential chemical parameters are phosphate, nitrate, and ammonia.
Co-Authors Afdal Afdal Hanif Budi Prayitno Hanny Meirinawati Lisa Fajar Indriana Muhammad Firdaus