石川県の七尾西湾におけるアマモ類の分布域と季節的特徴

It is well known that seagrass beds are important in coastal ecosystems. We investigated the distribution of seagrass beds of Zostera in Nanao Sei-Wan (western Nanao Bay), Ishikawa Prefecture in December 2011. As a result, 1,042 ha of Zostera beds and 6 ha of Sargassum beds were observed. As compared with those in 1990, the sizes of the Zostera beds have decreased to 83%, and the Sargassum beds have been reduced to 14%. Seasonal changes in Z. marina revealed that this species forms dense Zostera beds from spring to early summer, although it disappears from late summer to early autumn. We discussed this specific change from the viewpoints of water temperature and the lapse of time in the environment