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All Journal Marine Research in Indonesia Jurnal ALAMI: Jurnal Air, Lahan, Lingkungan, dan Mitigasi Bencana
Yanagi, Tetsuo
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Earth & Planetary Sciences

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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.
TIDE AND TIDAL CURRENT IN THE BALI STRAIT, INDONESIA Berlianty, Dessy; Yanagi, Tetsuo
Marine Research in Indonesia Vol 36 No 2 (2011)
Publisher : Research Center for Oceanography - Indonesian Institute of Sciences (LIPI)

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (2179.988 KB) | DOI: 10.14203/mri.v36i2.39

Abstract

Tide and tidal current model of the Bali Strait in Indonesia is produced by using a Coupled Hydrodynamical-Ecological Model for Regional and Shelf Seas (COHERENS). With its resolutions in the horizontal (500meters) and the vertical (4layers), the model well reproduces the four major tidal constituents, namely M2, S2, K1, and O1 tides, and their currents. Furthermore the model is used to investigate the tide-induced residual flow and tidal front in the Bali Strait. As a results, the tide-induced residual flow in the Bali Strait during the spring tide on May 16th in 2010 can be attributed to the variation of the strength of two eddies. The first one is the clockwise circulation in the shallow area at the wide part of the strait, while the second one is the small clockwise circulation in the south of the narrow strait. On the other hand, as suggestion from Simpson and Hunter (1974), the tidal front is determined by the value of log(H/U3) (where is the water depth in meters and the amplitude oftidal current amplitude in ms-1). The front detected by the image of sea surface temperature distribution from the satellite corresponds with the contour log(H/U3) of 6.5.
OCEANOGRAPHIC CHARACTERISTICS OF KLABAT BAY, BANGKA ISLAND, INDONESIA Sachoemar, Suhendar I.; Kristijono, Agus; Yanagi, Tetsuo
Marine Research in Indonesia Vol 32 No 2 (2007)
Publisher : Research Center for Oceanography - Indonesian Institute of Sciences (LIPI)

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (7904.544 KB) | DOI: 10.14203/mri.v32i2.437

Abstract

The oceanographic characteristics of Klabat Bay in Bangka Island of Indonesia were investigated by using a series of temperature, salinity, turbidity, TSS (total suspended solid), transparency, DIN (Dissolved Inorganic Nitrogen), DIP (Dissolved Inorganic Phosphorus), DO (Dissolved Oxygen) and chlorophyll-a data in the wet season (Northwest Monsoon) and dry season (Southeast Monsoon) of 2003, respectively. The observation results show that the hydro-oceanographic characteristics of Klabat Bay in the inner part and the outer part of the bay were dominantly influenced by the terrestrial and oceanic environment, respectively. High precipitation during the wet season decreased salinity, DO and transparency and increased total suspended solid (TSS), turbidity, DIN and chlorophyll-a within the bay. The reverse occurred during the dry season, except DIP.
SEASONAL VARIATION OF NITROGEN CYCLING IN MANILA BAY Hayashi, Mitsuru; Yanagi, Tetsuo; San Diego-Mcglone, Maria Lourdes
Marine Research in Indonesia Vol 32 No 2 (2007)
Publisher : Research Center for Oceanography - Indonesian Institute of Sciences (LIPI)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14203/mri.v32i2.440

Abstract

Seasonal variation in nitrogen cycling at the upper layer of the Pasig River estuary in Manila Bay was calculated during January 1996 to December 1998 by using the numerical ecosystem model. Chl.a and DIN concentrations are relatively low, river discharge is small, and solar radiation is strong from March to May in dry season. The main reason of low chl.a concentration is that the solar radiation is too strong. On the other hand, as DIN concentration is relatively high and solar radiation is optimum, chl.a concentration is relatively high from August to December in rainy season. Main source of DIN in rainy season is the vertical transport from the lower layer due to the strong estuarine circulation.
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.
WATER QUALITY IN MADURA STRAIT, INDONESIA Nugrahadi, M. Saleh; Yanagi, Tetsuo
Jurnal ALAMI: Jurnal Air, Lahan, Lingkungan, dan Mitigasi Bencana Vol 8, No 2 (2003)
Publisher : Badan Pengkajian dan Penerapan Teknologi (BPPT)

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Abstract

Observations on water quality based on physical chemical and biological properties of sea surface water were conducted on 13-14 September 2000 and on 14-15 May 2001 in Madura Strait, Indonesia. Particular emphasis has been placed on Surabaya and Porong estuaries and its surrounding coastal water, where rivers carry contaminated load from land and debouch. The observation showed that Madura Strait received a lot of pollutant from the rivers.
Co-Authors Berlianty, Dessy Hayashi, Mitsuru Iwan G. Tejakusuma Kristijono, Agus Nugrahadi, M. Saleh Nugrahadi, Mochamad Saleh Rahmania A. Darmawan Sachoemar, Suhendar I. San Diego-Mcglone, Maria Lourdes Seno Adi Seno Aji Tejakusuma, I. G.