Nugrahadi, Mochamad Saleh
Research Center for Oceanography - Indonesian Institute of Sciences (LIPI)

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SEASONAL VARIATIONS OF NUTRIENT BUDGETS IN JAKARTA BAY, INDONESIA Nugrahadi, Mochamad Saleh; Yanagi, Tetsuo; Tejakusuma, Iwan G.; Aji, Seno; Darmawan, Rahmania A.
Marine Research in Indonesia Vol 35, No 1 (2010)
Publisher : Research Center for Oceanography - Indonesian Institute of Sciences (LIPI)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14203/mri.v35i1.7

Abstract

This study aims to quantify the fluxes of carbon, nitrogen, phosphorus, and silicate in Jakarta Bay and use these flux data to gain an initial understanding of the biogeochemical processes occurring in the system. We investigated water, suspended matter and sediments fluxes from estuarine, coastal water and outside of the bay. Water samples were analyzed for dissolved nutrients, chlorophyll-phytoplankton abundance, and their composition. Suspended matter and sediment were analyzed for carbon and nitrogen. Nutrient concentrations were high in the rivers or estuaries and then decreased rapidly seaward. Calculation budget results showed that Jakarta Bay is a sink for DIP, DIN and DSi during dry season and rainy season. In the dry season, the system is in the slightly fixation condition ([nfix-denit] = 0.03 mmol N m-2 d-1). In contrast, denitrification exceed nitrogen fixation ([nfix-denit] = -9.74 mmol N m-2 d-1) in the rainy season. Moreover, the bay produced net carbon about 2.6-32 mmol C m-2 d-1.
DISSOLVED AND PARTICULATE CARBON IN JAKARTA BAY, INDONESIA Nugrahadi, Mochamad Saleh; Yanagi, Tetsuo; Tejakusuma, I. G.; Adi, Seno; Darmawan, Rahmania A.
Marine Research in Indonesia Vol 34, No 1 (2009)
Publisher : Research Center for Oceanography - Indonesian Institute of Sciences (LIPI)

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (8166.962 KB) | DOI: 10.14203/mri.v34i1.517

Abstract

In order to investigate spatial and temporal variability of dissolved organic carbon (DOC) and particulate organic carbon (POC), several samples were collected from five estuaries, inner part and outer part of Jakarta Bay. The samples were collected on 15 and 16 February 2007, a week after heavy flood in Jakarta Area, and on 16 May 2007. DOC concentration in February and May in Jakarta Bay ranged between 100-950 µg-C/l and between 0-850 µg-C/l respectively. POC concentrations ranged between 50-650 µg-C /l and 50-900 µg-C /1 in February and May 2007, respectively. Even though the concentrations between both periods were similar, the load of organic carbon from the land to Jakarta Bay showed a large contrast due to the different amount of freshwater input. The Total organic carbon fluxes from the rivers to the bay in February and May 2007 were 107.6 t d- C-(ton per day Carbon) and 42.7 t d-1 C, respectively.