[B-PT03] 生物鉱化作用（バイオミネラリゼーション）と古環境プロキシー

[BPT03-P01] Environmental DNA metabarcoding of foraminifera for biological monitoring of seawater and sediments

*前田 歩¹、西島 美由紀¹、井口 亮¹、鈴木 淳¹、湊谷 純平² (1.産業技術総合研究所　地質調査総合センター、2.独立行政法人　石油天然ガス・金属鉱物資源機構)

キーワード：環境DNAメタバーコーディング、浮遊性有孔虫、底生有孔虫

Foraminifera are adapted to a wide range of environments from the surface ocean to the sea floor and are even found in freshwater. Although foraminiferal assemblages and the chemical compositions of foraminiferal tests have been used previously to monitor regional environments, environmental DNA (eDNA) metabarcoding could enable the development of new environmental indicators. Here, we used eDNA metabarcoding to evaluate seasonal changes in benthic and planktic foraminiferal communities identified in seawater and sediments collected in June and August around the Takuyo-Daigo Seamount. In seawater, planktic foraminifers belonging to the family Candeinidae were dominant. Other families such as Globigerinidae and Globorotaliidae were detected more in August than in June. Our seawater samples contained a moderate amount of eDNA from benthic foraminifers, which may be attributed to the presence of suspended particles transported by deep-sea flow. Seasonal shifts of dominant species in the foraminiferal assemblages may be detected from seawater samples. Among benthic foraminifers, Monothalamids were the most common, as has been found in the other deep-sea regions. Our results suggest that the depth and the location of sediment collection can affect the composition of benthic foraminifers, but the timing of collection did not have a strong influence on benthic assmblages.