[B-PT03] Biomineralization and Geochemistry of Proxies

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

*Ayumi Maeda¹, Miyuki Nishijima¹, Akira Iguchi¹, Atsushi Suzuki¹, Jumpei Minatoya² (1.Geological Survey of Japan, 2.Japan Oil, Gas and Metals National Corporation All Rights)

Keywords:Environmental DNA metabarcoding, Planktic foraminifera, Benthic foraminifera

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.