Seaweed is sometimes described as the enemy of corals.Chemical substances from seaweed are said to have a negative effect on the coral.In addition to supporting the life of many aquatic organisms and providing a place of growth for egg laying and juvenile larvae, the algal floor decomposes organic matter in the water, absorbs nutrients and carbon dioxide, supplies oxygen, and so on. It plays a major role in purification.If you go down the sea floor, you will be able to see how beautiful seaweeds are bathed in the sunshine. Location:Hayama(Kanagawa,Japan),Rausu(Hokkaido,Japan)、Notojima(Ishikawa-Prefecture,Japan)