[A-CG43] 沿岸海洋生態系──２．サンゴ礁・藻場・マングローブ

[ACG43-P03] 海草による底質安定化機能を評価する

*田中 義幸¹、中村 隆志²、吉開 仁哉²、宮島 利宏³、灘岡 和夫²、渡邉 敦²、フェルナンド シリンガンン⁴、仲岡 雅裕⁵、錬平 諏訪⁶、ミゲル フォルテス⁴ (1.八戸工業大学　基礎教育研究センター、2.東京工業大学　環境社会理工学院　、3.東京大学　大気海洋研究所、4.フィリピン大学　海洋科学研究所、5.北海道大学　厚岸臨海実験所、6.森林総合研究所　関西支所)

キーワード：海草、ブルーカーボン

Seagrass rhizome and root systems trap organic matter, thereby stabilizing the sediments. Research on the strength of seagrass body against external forces in the laboratory has been carried out so far. However, the measurement in situ have not been conducted to the best of our knowledge. This study compared the resistance in situ against pulling up forces among four seagrass species, Halophila ovalis, Cymodocea rotundata, Thalassia hemprichii and Enhalus acoroides. Experiments were conducted at Tantangon Island, Busuanga, the Philippines from 13 to 14 September 2017. Dual steel wires (diameter, 1.5mm) were inserted below the rhizome and connected to Digital hanging scale by polyethylene line. After setting the wire the scale was pulled up and force (kg) for the rhizomes to be lifted up or broken were recorded. The largest species, Enhalus acoroides, showed the highest resistance with the values diminishing as plant size decreased. The results have some significant implications to the plants’ ability to stabilize sediments, store blue carbon and resist the impacts of strong waves brought about by climate change. Additional survey to evaluate the relationship between the resistance of each species and sediment grain size are scheduled. The biomass and reached depth of below ground part of each species would be also measured.