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Results
Development of Measurement Instrument of Dissolved Inorganic Nitrogen And Dissolved Inorganic Phosphorus
Arai, Rei (Osaka Prefecture University) | Akita, Kazuhiro (Osaka Prefecture University) | Nishiyama, Taichi (Osaka Prefecture University) | Nakatani, Naoki (Osaka Prefecture University) | Otsuka, Koji (Osaka Prefecture University) | Nishiyama, Takeichi (A Private Limited MULTI)
ABSTRACT Recently, measurement of certain environmental factors such as dissolved oxygen and chlorophyll using electric sensors has been realized. Such measurement is continuous and automatic, and is very important for monitoring the environment in coastal areas. However, it is difficult to continuously measure nutrient because data must be obtained by chemical analysis. This paper introduces a simplified measurement instrument using absorption rate measurement of processed water by visible rays. The effectiveness of the present method is demonstrated in field measurements in Osaka Bay. INTRODUCTION In coastal sea area, fundamental wastewaters contain high concentrations of nutrients and organic matter, which can lead to the so-called eutrophication phenomenon in coastal seas. Eutrophication of coastal waters has caused various environmental problems including red tide, anoxic water and so on. In order to deal with these problems appropriately, it is important to continuously and automatically measure these factors with high resolution in time and space, thereby providing a good understanding of coastal sea ecosystems. However, it is difficult to measure nutrient such as dissolved inorganic nitrogen (DIN) and phosphoric, silic acid (PO4), automatically. Measurement of these factors is most important because it is useful for understanding specific behavior of phytoplankton as the primary production. DIN, which is classified into nitrate (NO3โ), nitrite (NO2โ) and ammonium ions (NH4+), and phosphoric (PO4) are analyzed in a laboratory. Since we have to collect discrete samples or use research vessels with onboard facilities, it is difficult to measure in detail the fluctuation of nutrients in time and space. Degobbis et al. (2005) and Zou et al. (2001)have analyzed many seawater samples and strongly expressed a need for "in situ measurement" of nutrients. Gallegos et al. (1992) indicate that the inputs of nutrient-rich waters to coastal seas due to storms can have a dramatic effect on primary production.
- Water & Waste Management > Water Management (1.00)
- Materials > Chemicals (1.00)
- Energy > Oil & Gas > Upstream (0.86)
- Asia > South Korea > Yellow Sea (0.89)
- Asia > China > Bohai Basin (0.89)
A Consideration On In-situ Measurement Method of Matters At Sea Area
Arai, Rei (Osaka Prefecture University) | Nishiyama, Taichi (Osaka Prefecture University) | Iwasa, Natsumi (Osaka Prefecture University) | Nakatani, Naoki (Osaka Prefecture University) | Otsuka, Koji (Osaka Prefecture University) | Yamazaki, Tetsuo (Osaka Prefecture University)
ABSTRACT Recently, measurement of certain environmental factors such as dissolved oxygen and chlorophyll using electric sensors has been realized. Such measurement is continuous and automatic, and is very important for monitoring the environment in sea areas. However, it is difficult to continuously measure nutrient, hydrosulfide and so on, because data must be obtained by chemical analysis. This paper introduces a simplified measurement method of dissolved matter using absorbance spectrum in UV wavelength range and eigenvector of spectrum. The effectiveness of the present method is demonstrated. INTRODUCTION Recent interest in the absorption of CO2 in ocean may have been generated by relating flux of CO2 to global warming. Additionally, coastal eutrophication has caused many kinds of environmental problems including red tide and anoxic water among others. In order to deal with these problems appropriately and provide a good understanding of ocean and the coastal sea ecosystem, it is important to measure these factors by in-situ measurements with high resolution in time and space. Seafloor massive sulfides sources are found in the Okinawa Trough and the Izu-Ogasawara Arc near Japan (Halbach et al.1989), (Iizasa, K. et al. 1999), (Kato, Y. et al. 1989). Since these sources are relatively abundant in Au and Ag, there is a strong possibility for mining in the near future. It is natural that many studies of quantitative methods for estimating the environmental impact of mining operations have been reported by a number of researchers (Burns, R. E. et al. 1980), (Schriever, G.A. et al. 1997), (Trueblood, D. D. et al. 1997). One of the main reasons for the small number of studies on ecosystems around hydrothermal plumes is the fact that the instruments for in-situ measurements and the data concerning the environmental factors are far from sufficient
- Geology > Mineral (0.68)
- Geology > Geological Subdiscipline > Volcanology (0.47)
- Law > Environmental Law (0.54)
- Materials > Chemicals (0.35)
Fate of Bacterial Mat In Anoxic Environment For Development of Prediction Model For Seafloor Environmental Assessment: First Report
Nakajima, Yasuharu (Ocean Engineering Department, National Maritime Research Institute) | Ikemoto, Masahito (Department of Marine System Engineering, Osaka Prefecture University) | Arai, Rei (Department of Marine System Engineering, Osaka Prefecture University) | Nakatani, Naoki (Department of Marine System Engineering, Osaka Prefecture University) | Yamazaki, Tetsuo (Department of Marine System Engineering, Osaka Prefecture University) | Otsuka, Koji (Department of Marine System Engineering, Osaka Prefecture University) | Ishii, Takasada (Algae Bio-engineering Laboratory, Osaka Prefecture University)
ABSTRACT There are chemosynthetic ecosystems nearby deep-sea mineral and energy resources such as seafloor massive sulfides and methane hydrate. A prediction model that predicts the response of the ecosystems due to changes in environmental condition should be developed to assess the impact of deep-sea resource development on environment including chemosynthetic ecosystems. The relationship between the fate of bacterial mat, a model organism of chemosynthetic ecosystems, and environmental conditions in anoxic environment was studied by field work and culture of bacterial mat. In the field work, the occurrence, blooming and decline of bacterial mat on seafloor in the model field were observed periodically with the measurement of water temperature and the concentrations of dissolved oxygen and other chemical species in water. The occurrence of microbial mat was initiated with the lowering of concentration of dissolved oxygen (DO) in bottom water, and it was declined with the rising of DO concentration. In the culture of bacterial mat, the growth of bacterial mat was observed under anoxic condition. The results of the field work and culture of bacterial mat suggest that the fate of bacterial mat would be affected by not only physical and chemical conditions in environment but also predators of bacterial mat. INTRODUCTION On and under deep seafloor in the Exclusive Economic Zone (EEZ) of Japan, there are mineral and energy resources such as seafloor massive sulfides (Halbach et al., 1993; Marumo et al., 2008) and methane hydrate (Tsuji et al., 2004; Fujii et al., 2008). Seafloor massive sulfides are formed by deposition of metal sulfides precipitated from the fluids from hydrothermal vents on deep seafloor, where there are chemosynthetic ecosystems depending on nutrients that microbes synthesize with hydrogen sulfide or methane vented from seafloor (Karl, 1995).