In order to investigate the temporal variations of the current and temperature at 300 m in Suruga Bay, the current and temperature data obtained from a moored ADCP observation in the sea at the eastern part of the bay mouth were analyzed. Observed maximum current speed of the inflow and outflow were 57 cm/sec and 40 cm/sec, respectively. The mean current throughout the whole observing period was less than 1 cm/sec. The maximum and minimum observed temperature were 12.7°C and 7.0°C, respectively. The range of the temperature variation was as large as 5.7°C. Comparing with those values to those off Cape Muroto-misaki, those at Suruga Bay were 2.9°C higher for maximum, 1.1°C lower for minimum and 4°C larger for the range. Therefore, the deep sea water at 300 m in the bay can not be low temperature and constant.

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Sterile Ulva, a green alga has the potential to grow stably, and is expected to be an efficient resource of functional food containing various nutrients such as proteins and sulfur amino acids. Ulva lactuca was isolated from the“Marine Park” in Yokohama, and its growth rate (g-dry/m²·d) was evaluated using a model reactor at the surface of the sea. In these experiments, the growth rate of Ulva lactuca was recorded to be approximately 20 g-dry/m²·d which is estimated to be 10 times greater than rice yield in paddy field. Based on these data, we newly designed a float production system. D-cysteinolic acid, which was contained in Ulva lactuca as major sulfur amino acid, showed both activities of active oxygen scavenging and triglyceride reduction. Hence, the facility using enriched deep seawater has a potential for the production of valuable resource to prevent diseases.

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We previously reported that several functions of macrophage were enhanced by pretreatment with deep sea water (DSW) in depth dependent manner. However, the augmentative substances in DSW and the suppressive matters in surface sea water (SSW) have never investigated. In this study, we fractionated the macrophage activation factors (MAFs) from deep sea water by hydrophobic column chromatography and compared the content of the MAFs between SSW and DSW. In addition, we demonstrate that the one of MAFs in DSW is an endotoxin, a major component of outer membrane in Gram-negative bacteria.

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Recently, deep sea water is used for fishery, air-conditioning, products such as fresh water, face lotion and so on. It is very important to concern with cascade system of deep sea water, because deep sea water utilization system is very expensive and the amount of water drawn has limit. In this paper we estimate utilizable thermal energy and nutrient such as nitrogen, phosphorus and silicon on deep sea water intake facilities in Kochi, Toyama and Okinawa.

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A time-domain numerical method to predict in-line dynamics of flexible risers for upwelling deep ocean water has been developed. The analysis method is based on a swingby-swing technique with symmetrical vortices model. The symmetrical vortices model may accurately estimate instantaneous hydrodynamic forces for the Kc number lower than eight.
The effects of internal flow are considered by adding the momentum change of the internal flow, the frictional force on the inner wall of the pipe, the reduction of the internal pressure, and the reaction force of the intake flow.
To validate the present dynamic analysis method, motion measurements in steady current conditions and forced oscillation conditions in still water are performed. The results in steady current conditions show that the horizontal displacement of the pipe with internal flow is larger than that without internal flow due to the reaction force of the intake flow. The results in forced oscillation conditions demonstrate that the amplitude of the motion increases when the internal flow exists. The results in conditions with two different oscillation components showed that the present method have great potential for analyzing dynamic responses of CWP in irregularly load conditions.

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Shizuoka Profecture has been promoted the project for effective usage of deep seawater in Suruga Bay. The intake pipes of the deep seawater at depths 397m and 687m were laid in Senoumi Basin off Yaizu in August 2000. In order to contribute the promoting of the project, JAMSTEC carried out the mooring observation to grasp the characteristcs of current variations in the deep seawater intake sea area off Yaizu for about 3 months from November 1999 to February 2000, when the construction laying of deep seawater had not started yet.
We analyzed the time series data obtained on the flow direction and velocity, and water temperature and salinity in the wide range of depths. The results indicated that strong tide variations occurred in the periods of half a day and one day and other variations occurred in the periods of order several or ten days in even the depths down to several hundred meters. Being averaged each velocity components over the whole period of the mooring observation, strong southwestward current was predominant in the surface layer of the depths up to about 250m, while weak northward counter current existed in the middle and deep layers. Being used mean and standard deviation of absolute velocity, it was suggested that periodic current variations in the deep layer were bigger than we had expected.

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In case of one forces the sea surface layer water and jets it into the deeper layer, the forced plume entrains the ambient water and forms a newly mixed water body, whose density is greater than the surface water and less than the ambient water. It ascends to the position where the density is coincident with the continuously stratified layer's. Thus, a part of the deep seawater can be drawn up as a mixed water body. A mechanism is considered that compels the lesser density water into greater density one by the equilibrium of the water pressures. The lesser density column pressure is enforced by upraised water due to wave energy.

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Algal recovery on coralline-covered cobbles collected from an urchin-dominated barren ground of Southwestern Hokkaido was observed in two outdoor aquariums (35 litters in volume) using running deep-sea water of Toyama Bay (known as macro-nutrient rich sea water pumped from a depth of 321 m and warmed up to 11°C) from June to December in 2000. Top surfaces of cobbles were largely covered with encrusting or protuberant nongeniculate coralline algae (NCA); besides NCA, only tiny spots of an encrusting brown alga Ralfsia verrucosa and a few prostrates of red algae including Gelidium elegans were visible. In one aquarium, ten grazers of a snail Omphalius rusticus were added, while, in the other, the cobbles were kept without animals as a control. In the aquarium containing snails, 16 species of macroalgae appeared on refuges (e.g. underside of cobbles, crevices between NCA crusts or protuberances and surfaces of shells) and diatoms rarely covered the cobbles. The most conspicuous event was the rapid growth and maturation of ‘dulse’ Palmaria palmata and kelp Laminaria religiosa, which reached 30cm and 160cm long, respectively. G. elegans also grew up to 5cm long. In addition, R. verrucosa recovered and recorded ca. 10% coverage of top surface in one cobble. On the other hand, in the control, cobbles were rapidly covered with diatoms and macroalgae never recovered but most of NCA survived after a half year. However, introduce of snails after seven months facilitated the recovery of macroalgae including G. elegans and R. verrucosa by removing diatoms. These results, combined with the results of previous experiments using surface sea water of natural temperature, suggested the importance of nutrients as well as intermediate disturbance (i.e., grazing by snails, moderate than that of sea urchin) for the macroalgal recovery in the barren ground.

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To investigate the possibility of using deep seawater for rearing Japanese sandfish (Arctoscopus japonicus) for brood stock and to obtain basic knowledge for promoting the brood stock management, spawning, effect of diets on growth and maturity and changes in gonad conditions of the fish were examined from June to December in 1999. The mean To investigate the possibility of using deep seawater for rearing Japanese sandfish (Arctoscopus japonicus) for brood stock and to obtain basic knowledge for promoting the brood stock management, spawning, effect of diets on growth and maturity and changes in gonad conditions of the fish were examined from June to December in 1999. The mean temperature of the deep seawater used was around 5°C.
In the spawning test, 84% of the fish survived, and 43% of the females spawned from October to November. Their first spawning was 2 months earlier than that of the wild ones.
The growth of the fish of experimental Group A, which were fed on a dry diet, was almost the same as that of Group B, which were fed on a fresh diet, but the maturity rate of Group A was superior to that of Group B. The maturity rate of the females of Group A was 77% versus 33% of Group B.
G.S.I.(gonad weight/body weight excluding the internal organs×100)did not change in most of the fish from June to July, but afterwards it increased in more than half of the fish. The mean total length of mature females and males were 15.5cm and 13.8cm, respectively. These lengths nearly coincided with the size of the smallest mature wild fish.
Thus, these investigations proved that the brood stock management of this species using deep seawater is possible and suggested that some rearing conditions in deep seawater would hasten the spawning time. This will be very effective to reduce the mortality of the released fish, because the size of young fishes produced from the brood stock will be larger than that of the wild ones when they migrate to the sea after release. This study also suggests that in order to raise the spawning rate, a suitable diet must be chosen, and the growth of the fish should be promoted so that they can get mature by August.

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Responses of phytoplankton community in subtropical surface waters by the addition of deep ocean water (DOW) were examined under natural sunlight. Two culture experiments were carried out in September and October, 1999; DOW collected from ca 800 m was mixed into the surface water at high concentrations (13 and 27% (v/v)) in 9 l polycarbonate bottles and incubated in an outdoor incubator (EXP 1), and DOW from ca 400 m was daily added to ca 800 l of surface water at low concentrations (0.6 and 1.2%) in polyethylene bags moored in a harbor (EXP 2). Both experiments showed that the DOW enrichment, equivalent to more than 0.15 μmol nitrate l^-1 day^-1, increased concentrations of chlorophyll a (Chl a) after a lag period of 5 to 7 days and reached maximum concentrations at 10 to 12 days after the start of the experiments. The maximum levels of Chl a were proportional to the total addition of nitrate; 1 mol nitrate = around 1.4 g Chl a. The specific rates of increase of Chl a concentration were also in proportion to the amount of added DOW. Low Chl a share percentage of>2 μm fraction, such as 15% of total Chl a, in the initial surface water was changed to more than 70%. These results indicated that the DOW enrichment effectively enhanced the growth of nano- and microphytoplankton. Within those phytoplankton, some diatom species, being extremely less abundant in the subtropical surface water, increased rapidly. Results indicate primary production even in subtropical ocean can be raised effectively to enhance effective phytoplankton community for fish production by the DOW enrichment. Since the enhancement of the phytoplankton growth by the DOW enrichment was observed after 5 to 7 days, DOW should be added to keep at least 0.1 μmol nitrate l^-1 day^-1 during the lag period for initialing the fertilization effects in the subtropical waters.

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In Suruga Bay, there exists deep sea water more than a depth of 2, 500 m, and a water mass having different multi-1ayer intake water (five levels of 4 types) is observed. The total design of the deep seawater intake pipe and its laying procedure are described. There are two intake pipes; one for the Kuroshio origin deep seawater from a depth of 380 m, and the other for the subarctic origin from 680 m. The depth of 687 m and the extension length of 7, 273 m for the subarctic origin water, are the deepest and the longest records in our country.

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