A risk assessment of Tributyltin (TBT) in Tokyo Bay was conducted using the Margin of Exposure (MOE) method. Risk to marine life of Tokyo Bay exists when no-observed effect levels are less than estimated environmental concentrations (i.e. when MOE values are less than one). Sources of TBT in this study were assumed to be commercial vessels in harbors and navigation routes. Concentrations of TBT in Tokyo Bay were estimated using a three-dimensional hydrodynamic model, ecosystem model, and chemical fate prediction model. These models calculate temporal and spatial distributions of TBT concentrations at a fine scale: 1 km x 1 km grids and at a time step of one day. The risk assessment was conducted at the species level using a common marine species of the Bay: the Japanese short-neck clam, Ruditapes philippinarum. The assessment endpoint was detined as TBT induced growth reduction on the Japanese short-neck. NOEC for the Japanese short-neck clam with respect to the endpoint was estimated from experimental results published in the scientific literature. MOEs for Japanese short-neck clams were estimated for the years 1990, 2000, and 2007. There was no risk for these cases, and the risk from TBT decreased temporally in Tokyo Bay.

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To detect slight changes of oceanic carbon cycle in response to atmospheric C02 increase, high precise measurements of oceanic C02-system properties are necessary. For the purpose, we examined to improve a coulometer (model 5012,UIC), which is generally used to detect a temporal increase of total dissolved inorganic carbon (TC02) in the ocean. In addition, we produced in-house reference materials (RM), which are traceable to certified reference materials (CRM), to monitor performance of a TC02 measuring system. For the coulometer improvement, we improved the photometric detection part of a coulometer to minimize variations of light source intensity. The repeatability was improved to be 0.03%(relative standard deviation), which was previously 0.08%. Measurements of RMs showed no statistically significant changes over approx. 2 years. The RM was judged to be useful as a standard for monitoring TC02, It is also useful for reducing systematic erros of TC02 values, which are

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Habitat information on aquatic animals can be acquired easily using under water acoustic biotelemetry. The biotelemetry has been developed recently along with developments of micro-electronics. In this paper, an attempt to track red tilefish using ultrasonic coded transmitter and receiver system both in the Wakasa Bay and the Maizuru Bay was introduced. The Wakasa Bay is open to the Japan Sea and the Maizuru Bay is the typical semi-closed waters. Tracking in the Maizuru Bay was easier than in the Wakasa Bay, and some fish were passively tracked more than 100 days. The result indicated that the biotelemetry study in semi-closed water has a big advantage in order to study fish ecology. Some fish stayed relatively longer periods in the Maizuru Bay showed circadian rhythm. Successive tracking records can reveal the ecology of fish as well as their position. Behavior of hatchery-reared fish was different from that of wild fish. The under water acoustic biotelemetry may be a tool to evaluate the fish quality for release.

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Wavelet spectrum analysis was applied to sea surface temperature images derived from NOAA/AVHRR for the area around Japan. A two-dimensional wavelet spectrum for each scale (wave number) was computed at each position using the Haar wavelet basis, and then a specially-averaged wavelet spectrum was calculated for each scale. The wavelet spectral slope derived from the averaged wavelet spectra was approximately -2.0 in the wavelength range between 4 and 280 km in the Kuroshio area and the East China Sea, while in the Japan Sea and the Perturbed area (between the Kuroshio and the Oyashio), the slope was approximate ly -5/3. However, the calculation of the slope at every position showed the values of the slope were randomly distributed, and even in the Japan Sea and the Perturbed area, the number of positions where the slope was -5/3 was very small (about 10%). The results gave insight into the structure of horizontal turbulence, which would be impossible using a traditional Fourier transform approach.

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TRITON buoy system consists of unmanned mooring system in the ocean. In some areas where the buoy are moored, observational instruments are detached and stolen. Such destructive acts are called Vandalism. Japan Marine Science and Technology Center (JAMSTEC) tries to prevent Vandalism, of course. Since the cycle of deployment and recovery of each buoy is about one year, only once a year prevention can be tested. So far, the following prevention was proved to be remarkably effective; (1) Change of towers in material from alminium to stainless, (2) Change of antennas in shape from a whip to a disk.

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