CREATION OF ORGANISMS DUE TO CHANGES IN THE CROSS-SECTIONAL STRUCTURE OF TIDAL FLATS

Abstract

 In coastal areas where the production of short-necked clams is significantly decreasing, a new tidal flat construction method using dredged mud is required to construct a tidal flat that improves the production. The development of new utilization technology is desired. In this study, the effectiveness of dredged mud utilization was evaluated from sediment analysis and benthic organism survey, targeting tidal flats created by sand covering with a time lag after dredged mud was added. At the point where the sand cover was completed, a layer of dredged mud and sand was confirmed on the sand layer, and it became clear that many organisms lived in that environment. In the target tidal flat, a good sand-mud mixed layer is formed as a place for clams to settle, but the nutrient state is phosphorus-restricted, so the growth of clams is not sufficient. The amount of algae is considered to be the cause of the suppression of the growth of clams and the like. For the production of short-necked clams, a source of phosphorus for tidal flats is required, and dredged mud is expected as a source of phosphorus.