From August 6 – September 8, 2023, 9 CSSF team members supported the Korea Institute of Ocean Science and Technology (KIOST) aboard the R/V Isabu for the Western Pacific Seamount 2nd Exploration Expedition. The expedition was part of the ‘Selection of prospective mining area for cobalt-rich ferromanganese crust in western Pacific seamounts: 3D resource estimation and environmental impact evaluation’ project, funded by the Korean Ministry of Oceans and Fisheries. An additional project that was conducted aboard the R/V Isabu, ‘Development of technology for designating and managing ocean conservation areas using AI deep learning’, was conducted by KIOST. Participants were largely from KIOST but included one representative from Inha University. KIOST’s objectives were to: 1) to select the first mining area, scheduled for 2026 and 2) to conduct environmental research as mandated by the International Seabed Authority. Work requiring the use of ROPOS included: collection of imagery, as well as collection of prospective mineral resources and biological samples on and around the selected seamounts.

There were two legs: the first leg focused on geology, and the second focused on biology.

Leg 1: The focus of Leg 1 was on geology. We performed 11 dives on 3 seamounts. These types of seamounts are called guyots, which are underwater volcanoes that have been parted off or flattened on top. KIOST was interested in the ferromanganese crusts that form on the edges of these seamounts for potential mining. We performed 3 visual surveys around the circumference of the guyots totaling 99 km and drilling of cobalt-rich crust along predetermined paths. We attempted drilling for 66 crust samples and were able to successfully collect 63!

Leg 2: The focus of Leg 2 was on biology, primarily habitat mapping of vulnerable marine ecosystems and collecting imagery also to be used for 3D modeling of corals. We performed 9 dives at 2 seamounts. Across 2.4 km and within 66.2 hours we conducted 5 video surveys and collected high-resolution mosaic imagery for photogrammetry. Our team flew ROPOS in 3 circles for the collection of corals, very specific sponges, and opportunistic squat lobsters and shrimp. The biology samples were collected using the suction sampler, grabs, scoop (plastic and metal), sediment push cores (top 5 cm of sediment), as well as a baited trap. We obtained seawater samples using ROPOS-mounted Niskin bottles and a hand Niskin and took measurements of environmental parameters using the CTD with oxygen probe mounted on ROPOS. We recovered 1 bio box that had been deployed on a small seamount situated in between two larger seamounts. We also set up 1 mooring then performed a recovery of an CTD-LADCP at specified target sites.

The main highlight for the KIOST team was that based on the successful performance of KROCS and the results from this expedition, they are now proceeding with a new multi-year program!

There were several highlights for our team. This was our team’s first real work with our Korean Remotely Operated Coring System (KROCS), which we tested earlier this year in the Indian Ocean. This was a new operation for CSSF and is the only time our team has ever drilled for a hard substrate like seafloor crust. A professional highlight for CSSF’s Operations Manager, Keith Tamburri, was being able to execute the collection of 66 cores with KROCS as opposed to the usual ~18, which he found very rewarding. Before, our team used our Remotely Operated Coring System (ROCS), which allowed ROPOS to collect 4 massive sulphide cores at a time, at 1 m long. Now, with KROCS, ROPOS can drill 10 cores, but they are a bit shorter, at 35 cm long. On this expedition, our recovery rate came out at 86%, which is really good! Our team also had a new setup for mobilisation, with a new 40-ft flat rack, and it was our first time operating in Guam in ~25 years with a new group of supporting agents. A personal highlight for Keith T. was finding a crust core that had a section of carbonate imbedded between two sections of seafloor, which he found interesting.

Our team faced some challenges on this mission. The entire job was delayed by 1 week when a typhoon hit South Korea, which temporarily prevented the R/V Isabu from getting to port in Guam. During the expedition, our team spent much of the time dodging storms that were beginning to form and had to halt dives for 3 days due to inclement weather. At one point, it was decided that the ship was going try to move to sites that weren’t going to be impacted by strong weather, and that meant that it took more time to steam to locations. Despite this, our team was still able to accomplish all our priorities!