Development of Environment-Friendly Base Materials for Seaweed Beds Using Recycled Materials and Its Long-Term Monitoring

The area of seaweed beds along Japanese coasts has decreased by approximately 40% in the last 40 years due to climate change and human activity. In addition, there are similar concerns regarding coastlines worldwide. Thus, it is critical to recover seaweed communities quickly to maintain marine plants and environments. On the other hand, the treatment of disaster waste like decomposed granite and Shirasu in Kyushu region is getting a big problem when a disaster due to heavy rain has occurred. Large amounts of waste material such as scrap ceramics and gypsum are discharged from the ceramics industry in the Saga and Nagasaki Prefectures of Kyushu, Japan. The effective use of disaster and industrial wastes (problematic soils, scrap ceramics and gypsum) represents an important problem that must be solved in the Kyushu region of Japan. The objective of this study is to develop environmentally oriented base materials for seaweed beds with a low environmental load using several recycled materials from disaster and industrial wastes. The developed base materials were placed into the actual sea area in September 2021, and monitoring began. A discussion of the results of long-term monitoring over 1 year is presented.