Nihon University Funabashi, Chiba, JAPAN

hotta@ocean.cst.nihon-u.ac.jp

　

Mekong delta is having big potentiality agriculture and important place in social-economic development of Vietnam. So every year 2.000.000 ha land in north of delta is has frequently over flow by flood of Mekong River. The research safety flood area planning for peoples now is very necessary problem.

　

This problem has related with many another problems like water resource planning, traffic planning, urban planning, cultivated land planning and society problem. Base on the research to have a connection with that problem, we can solve and to bring out the standards point for define the place, size, form and architectural solution for safety flood area in Mekong delta.

　

　

Centre of Marine Study, Nanjing University Nanjing, CHINA

wangying@nju.edu.cn

　

Located in the South Coast of Hainan Island, Yalong Bay ranks first national holiday resort of China in the South China Sea. The bay is surrounded by 20-30 m high of granite hills landside, on the south faces to the open sea. A total water area of the bay is 86 km², and there are five islands with fringe coral reefs distributed in the bay. Annual average temperature is 25°, water temperature of the sea during January is still higher than 24°, colorful coral reefs can be observed through transparent sea water and reached to 8 m water depth. All of these conditions form an ideal wide range of swimming resort all year around especially accompanied with fine grain sandy beaches 17 km long surrounding the bay water.

　

Seasonal coastal marine survey and monitory have been carried out by Nanjing University since 1994, the observation items are including regional geomorphology, sedimentology, physical, chemical and biological oceanography etc. Through the multidisciplinary, it has been carried out a planning as national marine tourism resort in the Yalong Bay. The development of Yalong Bay is not limited on land, such as Hotels, Swimming ground, museum, mangrove forest park, but also develops submarine sightseeing veranda, submarine theatre, marine fishing reefs, water sport and scuba activity area, Yacht club and docks in the Yalong Bay. At the same step of development there, It has set up a master plan for eco-environment protection and renovation of the Yalong Bay, the program includes swage treatment and purification, mangrove forest renovation, Beach protection and nourishment, coral reef protection, sand barrier and sand dune ecological maintain etc. The integrated developing planning and management of the area has increased economic income as well as the beautiful landscape environmental qualities.

　

　

¹Technical Center, Okumura Engineering Corporation Minato-ku, Osaka, JAPAN

munehisayoshida@okumuradbk.co.jp

　

²Department of Civil Engineering, Kinki University Higashi Osaka, Osaka, JAPAN

　

Porous concrete has many continued voids, and it is effective as adherent basis of marine organism. This paper presents the results of an investigation undertaken to develop additional data on the properties of the porous concrete mixed with granulated fertilizer. Granulated fertilizer dissolves nutrient composition which is useful for the growth of algae in long term. Test plates were installed in SETO Island Sea, Japan in order to evaluate the effectiveness of porous concrete with fertilizer. Size of the test plates for experiment was 2 m in height and 1 m in width. Test plates were fixed undersea on the upright seawall. Properties of three types of specimen were evaluated experimentally, such as porous concrete, porous concrete with fertilizer and normal concrete. Experimental term was two years from September 1999 to March 2002, and adherent of algae on test plates has been observed.

　

As a result, compressive strength has been stabilized over 16 MPa. The algae succession has been observed on all test plates, and biota of circumference was formed on test plates. The number of large algae on porous concrete was more abundant than normal concrete. Then, the number of large algae on porous concrete with fertilizer was the most abundant. And, continual elution of the fertilizer component was also detected. Seaweed rapidly adheres to porous concrete. Seaweed adhesion to porous concrete was found to be more predominant than that to normal concrete. Due to mixture of granulated fertilizer and iron ore, there tended to be a high degree of seaweed cover and wet weight. It is concluded that porous concrete with fertilizer is effective as adherent basis of algae.

　

　

¹Graduate School of Engineering, The University of Tokushima, Tokushima, JAPAN

n-yoshi@sogokagaku.co.jp

　

²Graduate School of Engineering Osaka Prefecture University, JAPAN

　

Artificial lagoons have been constructed in the enclosed sea area in order to conduct the restoration of water quality and marine organic habitation. An artificial lagoon with 120 m long, 50 m wide and 2 m deep was constructed in 1996 in Osaka bay, Japan. Water exchange of the water body in the lagoon was performed periodically through a permeable rubble-mound breakwater of 50 m wide by the tide. The purpose of this study is to evaluate the environment of the lagoon by using the sessile organisms community structure and examine the management of the lagoon environment. The survey of the ecosystem was carried out in the permeable rubble-mound breakwater of the seaward (area A) and the overside (area B), and riprap walls inside the lagoon (area C) in summer and winter of 1998.

　

The sessile organisms community depended largely on the area. The organism community in area A was composed of diverse organisms in trophic levels, primary producer, primary consumer and predator. Though there were also seaweeds, bivalves, snails, Amphipoda and other animals in area B came in and out from sea water, the biodiversity and the biomass in area B were lower than in area A. Riprap walls (area C) were thickly overgrown with green algae (Chlorophyceae: Family Ulvaceae) and the biodiversity in a lagoon was very low. It was revealed that green algae became a dominant species in such a calm environment as a lagoon. Generally speaking, the presence of green algae in an ecosystem is taken as a positive sign and as better improvement of the water quality due to the assimilation of nutrients by a green algae. However when herbivorous animal were few and a lot of green algae decomposed on a seabed, the eutrophication had occurred. As a result for better control of an artificial lagoon environment, green algae must be regularly harvested.

　

　

¹Institut of Ecology and Evolution Problems, Russian Academy of Science Moscow, RUSSIA

　

²Department of ichthyology, State University of Moscow Moscow, RUSSIA

borislov@gol.ru

　

A study of a biodiversity and structural connections in coastal and estuary ecosystems of Nhatrang Bay of the South-China Sea was general direction of our works. The researches on standard sections and horizons with decades intervals were carry out with hydrobiological and biophysical methods. The data analyzed during of a line years allowed to conclude that phytoplankton communities of the coastal ecosystems were composed of 48% - species of a tropical type, 28% - species cosmopolite, 14% - species are boreal-arctic, 3% - species are tropic-boreal-arctic type, 2% - species tropic-antarctic type. Zooplankton of coastal zone was adduce by herbivorous crawfishes, in a smaller degree of polychaete larvas, setigerous (chaetognatha), appendicularia and salpae.

　

The presence a batch dropper spawning and a longing of a spawning period for majority local species of fishes, probably, is a connected with absence of sharp fluctuations in plankton production and relative stability (regular periodicity) hydrological and weather conditions in this region. White bait of the majority of species (72%) appertain to plankton eating, from them to single - 22% and to shoal-group 50 percent. White bait of fishes 13% to next-bento-eating. As an example of researches of migration behavior of fishes the circuit of daily migrations mullet white bait in coastal zone, in time having flown having cast the phenomena was developed.

　

On the basis of express biophysical methods of study of fluorescence of water environment, the technique of definition local, climax and succession of a way of development biocenosis is developed, are described and the features and character of formation of primary production in a gulf and of neighbor water area are appreciated. The seasonal nature of its formation and connection with the weather and natural phenomena, characteristic of the given region is shown.

　

A research an increasing of anthropogeneous pressing with estimate of a physiological states of phytoplankton, phylobentos, gastropoda and others inhabitant of coastal coral reeves have been carrying out by us during several last years. We have shown that these most productive biotopes were in a constant oppressed condition. Some of them were a gradual changing and degradation.