講演情報
[G-P-44]Ocean Decade Project COESS: Seep Ecology of Torigakubi Spur, Joetsu Basin
*Glen Tritch Snyder1, Hitoshi Tomaru2, Yoshinori Ono2, Natsuki Kaneko2, Natsuki Oneda2, Yoshiki Honma2, Shinsuke Aoki3, Yasumasa Sakai4, Gen Takatori4, Shohei Ito5, Hashimoto Yuichi6 (1. AORI University of Tokyo, 2. Department of Earth Sciences, Chiba University, 3. Faculty of Agriculture, Kagawa University, 4. Kobe University, 5. FullDepth Co.LTD., Tokyo, 6. Toyama Bay Lab)
キーワード：
cold seep、seafloor lander、UN Ocean Decade、cnidarian、gas hydrate
Project COESS (Chemistry, Observation, Ecology of Submarine Seeps) was founded and endorsed by UNESCO in 2022 as part of the UN Decade of Ocean Science for Sustainable Development. The project currently involves 27 researchers from 16 research institutions with the goal of studying cold seeps and hydrothermal vents and promoting education of the public regarding these unique ecosystems.
In October, 2023 we deployed to Fugro Shallow Environmental Landers (SFEL) on Torigakubi Spur, offshore Joetsu in order to do long-term monitoring of an active methane seep area. The two SFEL are still deployed and will be recovered in October, 2024. During the past year they have been measuring changes in salinity, temperature, pressure, turbidity, pH, oxygen, and methane. Located roughly 60 km from the epicenter of the Noto earthquake in January, the landers also will provide an opportunity to see the effects of seismic activity on methane seeps.
In June, 2024 we deployed a prototype Full Depth Drone to document the conditions of the landers prior to recovery. We found the landers covered with dark sediment or biofilm, while the internal parts appear to be colonized by microbial mats. Squid, sea cucumbers, whelks, snow crabs and shrimp were also found living near or on the landers (Fig. 1). We also noted several interesting features in the area including a fresh exposure of shallow gas hydrate and a “garden” of cnidarians. A number of cnidarians occurring in Torigakubi Spur exist in solitary and branching tubular form and also host a number of other macrofaunal species clinging to their surface including other cnidarian epibionts. During the same drone deployment, we also observed seafloor markers left by earlier ROV deployments and hope to compare our new video footage with video footage collected by members of our team over 10 years ago.
In October, 2023 we deployed to Fugro Shallow Environmental Landers (SFEL) on Torigakubi Spur, offshore Joetsu in order to do long-term monitoring of an active methane seep area. The two SFEL are still deployed and will be recovered in October, 2024. During the past year they have been measuring changes in salinity, temperature, pressure, turbidity, pH, oxygen, and methane. Located roughly 60 km from the epicenter of the Noto earthquake in January, the landers also will provide an opportunity to see the effects of seismic activity on methane seeps.
In June, 2024 we deployed a prototype Full Depth Drone to document the conditions of the landers prior to recovery. We found the landers covered with dark sediment or biofilm, while the internal parts appear to be colonized by microbial mats. Squid, sea cucumbers, whelks, snow crabs and shrimp were also found living near or on the landers (Fig. 1). We also noted several interesting features in the area including a fresh exposure of shallow gas hydrate and a “garden” of cnidarians. A number of cnidarians occurring in Torigakubi Spur exist in solitary and branching tubular form and also host a number of other macrofaunal species clinging to their surface including other cnidarian epibionts. During the same drone deployment, we also observed seafloor markers left by earlier ROV deployments and hope to compare our new video footage with video footage collected by members of our team over 10 years ago.
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