Towards a Beautiful, Safe, and Lively Seashore
MASAHIKO ISOBEThe University of TokyoGraduate School of Frontier ScienceDepartment of Environmental Studies
The seashore is the connecting point, and boundary, of the sea, the land, and the air. It is also a point where freshwater changes to saltwater. Waves, flows, and winds are generated at seashores. Thus they have special features, different from the land or sea.
Japan is an island country surrounded by long shorelines. The total length of the shorelines is about 35,000 km (ca. 22,000 miles). One-third of them are natural seashores, and the rest are artificial. The total length of the shorelines of sand, cobble beaches, and muddy beaches are less than 10,000 km (ca. 6,000 miles).
Only 32% of the cities, towns, and villages in Japan are on seashores. But 60 million people live at seashores, industrial sales at seashores is 47% of the gross national sales of industry, and commercial sales at seashores generate 77 % of the amount of money earned by all commercial industries in Japan. Seashores are therefore important places. They support large populations, and many economic activities.
The Nature Interface interviewed Prof. Masahiko Isobe, head of the Department of Environmental Studies at the Graduate School of Frontier Science at the University of Tokyo, about the importance of seashore environments.
Three Components of Seashore Environments
Seashores have three components related to the natural and social environment: 'Nature and ecology,' 'Safety and disaster prevention,' and 'development and utilization.' Professor Isobe talked with Nature Interface about the roles of these three components.
Seashores and the shallow parts of the sea around them are good environments for marine organisms, since oxygen dissolves through the ebb and flow of the tide and the movement of the waves. These areas also receive a lot of sunlight. The surface area of seashores is slight compared to the entire area of the globe, but they are important for life; more than one-half of marine organisms live or breed there. Seashores are abundant with plants and animals such as fish, microbes, benthos, plankton, birds, seaweed, shore plants and forests.
Shore areas have reef areas, sandy and muddy areas, tidal flats, macrophytic beds, etc. Macrophytic beds are created on reefs, and are important places where fry grow. Tidal flats are important wetlands in Japan, which is surrounded by the sea. Tidal flats play important roles in biological production through their regulation of the weather and purification of the air and water, and are key areas for environmental conservation. Tidal flats are also good recreational places for such activities as shell gathering, fishing, and bird watching.
Macrophytic beds are described as sea forests, with various species of seaweed and sea grasses. They are also where fish live and spawn. Nitrogen and phosphate are absorbed, and oxygen is photosynthesically supplied by seaweeds and sea grasses.
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