DISTRIBUTION CHARACTERISTICS OF WATER QUALITY, SEDIMENTS, AND BENTHOS IN THE ARIAKE SEA AREA

In recent years, the Ariake Sea environment has become severely degraded, resulting in changes in biota, a marked overall decrease in the number of species, frequent outbreaks of red tides, and the deterioration of water quality and the sediment environment. In this study, we examined the relationship between increases in red tide frequency and duration and fluctuations in the aquatic environment. We also investigated the distribution of sediments, and the correlation between benthic species distribution and sediment type. The results show that interannual fluctuations in water quality (water temperature, transparency, and nutrient levels) were responsible for the increases in red tide outbreaks. The Ariake Sea was divided into zones on the basis of the granularity and chemical characteristics of the sediment. The results showed differing number of benthic species in each zone, demonstrating a relationship between the sediment environment and benthos distributions.