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Observations on the development of seaweed communities on concretepanels suspended at three different slope angles – 0° (horizontal),45° (inclined) and 90° (vertical) – were carried out atUranouchi Inlet, Tosa Bay, southern Japan. Each panel had two opposite20 × 20 cm areas, which were affixed with six pieces of 6 × 9 cmacrylic plate on which algal communities were allowed to colonize. The panelswere suspended 1 m below the sea surface from a floating platform fora period of 6 weeks. The experiments were repeated nine times fromAugust 1996 to October 1997. Young thalli could already be recognized on the panels after 3–4 weeks. Thetype of algal community developing on a panel varied with the slope angleas well as the period of suspension. These were classified into the threedominant green algal genera: Ulva, Enteromorpha and Cladophora. The cover and biomass of particular species were clearlyinfluenced by the slope of the substratum.

An estimation method for dissolved oxygen (DO) budget is described and seasonal variations of the DO budgets in Uranouchi Bay, a typical semi-enclosed inlet, are estimated. The formation mechanism of anoxic water mass in the inlet is investigated on the basis of the results.In the upper layer, although phytoplankton produces abundant oxygen from spring to fall, 60% of the oxygen produced escapes to the air above. In the lower layer, biological-chemical DO consumption of water accounts for 70% of the total DO removal. The DO consumption by respiration of cultured fish increases to 20% of the total DO removal in the fall. The DO production by phytoplankton accounts for 80% of the total DO supply in spring and fall, but for only 25% in summer. The DO transport through tidal exchange from the outside of the bay increases to 50% in summer. The DO transport through vertical mixing decreases to 7% of the total in July and accounts for 20 to 45% in spring and fall.The anoxic water mass in the lower layer ...

In Uranouchi Bay, the external water density becomes higher than that of internal water in the summer stratification season, and the external saline water intrudes into the bottom of the bay at the spring tide. Much heat and oxygen is also transported into the bottom layer along with the water intrusion. Although the strong anoxic water is formed from the beginning of June in the bottom of Uranouchi bay, anoxic water masses on the bottom disappeared for a while after the intrusion, and the bottom water temperature suddenly rose about 2 to 3°C in a few days, but anoxic water was formed again at the next neap tide due to the high DO consumption and the upwelling of bottom anoxic water. These conditions killed a large number of cultured yellowtail fish, as occurred at the beginning of September 1988.

Seasonal variations of the tidal exchange ratio, interzonal exchange fluxes, and dissolved oxygen (DO) balance in Uranouchi Bay were estimated using a two-layer box model. The formation mechanism o...

Values of diffusion coefficient and load of dissolved or suspended matter in the same sea areaand period must take same values regardless of models. When over two models were applied tothe same sea area, the adequacy of applied model can be examined by comparing the diffusioncoefficient and load of dissolved matter. Therefore, two models-one layer one box model and one layer four box model-were applied to Komame Bay in Kochi prefecture. The accuracy of box models which were applied to Komame Bay was investigated from diffusion coefficient in the section at the mouth of the bay, load of dis-solved oxygen and inorganic nitrogen into the bay.

When the members of a crawl, the pipes, ropes and nets are fouled with acron barnacles in the sea, the hydrodynamic resistance increases and the crawl is broken under condition where the seas are rough.In this paper, laboratory tests were conducted to determine the hydrodynamic resistance of pipes and plane nets which were fouled with the acron barnacle.The drag coefficient (CD) of barnacle covered pipes placed at a right angle to the stream was 1.1 where the range of the Reynolds numbers were between 2, 000 to 40, 000. This result suggested that the boundary layer flow separated at the same point because the surface of the pipe was very rough.The drag coefficient (CD) of barnacle fouled plane nets placed at a right angle to the stream depended on the ratio of the solid area to the total area of the net ( ?? ) rather than on the Reynolds number. That is where CD=0.85/(1- ?? )2 at ??

Equations for surface waves and interfacial waves and their relations in a basin with depth iscontinuities were given by Lamb, Le mehaute, Takano, and Rattray. If the length of the bay is much larger than the width, and the curvature of the bay aixs is small, it is possible to consider that the surface long waves, i.e. the tidal waves and the interfacial long waves generated in these basins can be treated as a one dimensional problem. The bay can be divided into many rectangular segments as shown in Fig. 1, and each of the divided segments corresponds to any of the model segments as shown in Fig. 2. The basic equations for the surface and the interfacial long waves in the model canals are given on the basis of Lamb and Takano's theory. The numerical computations for the surface long waves and the interfacial waves generated in a two layer basin with variation in depth and width. can be carried out by using the basic equations in the model canals.