From April 21 – May 22, 2024, 10 CSSF team members supported the Korean Institute of Ocean Science and Technology (KIOST) aboard the R/V Isabu for their INDEX2024 Expedition. Participants included scientists from the University of Washington (UW) and the National Oceanic and Atmospheric Administration’s Pacific Marine Environmental Laboratory (NOAA, PMEL). [Add: Science Team objectives]. ROPOS was required to operate specialised water- and gas-tight samplers in deep-sea environments.

There were 2 focuses for the ROV work on this expedition: 1) water sampling and biogeochemistry, and 2) multibeam bathymetry. The water sampling and biogeochemistry portion was led by David Butterfield, Senior Research Scientist at NOAA, PMEL (program soon to be passed to Tamara Baumberger; NOAA, PMEL), and Dave was anticipating top-quality samples. The water- and gas-tight samplers that ROPOS used on this expedition were developed by Marvin Lilley (Professor Emeritus in Chemical Oceanography; UW) and have been in use since the mid-1990s. Our team’s Will Glatt (Science Manager, at the time) and Peter Lockhart (Manager, Mechanical Systems) had designed wedges and 3D-printed brackets to cradle them during transport. We ended up collecting 32 major water- and gas-tight samples. We also performed some separate general seawater sampling with ROPOS’s mounted Niskins and collected geological and biological samples.

A highlight for the science team, specifically for Dave Butterfield, was the sample collection. He said that he had never been on a cruise with so many high-quality gas samples before!

A highlight for Keith Tamburri, CSSF’s Operations Manager, was our team’s ability to fully capture the areas of interest on the seafloor with the multibeam sonar mounted to ROPOS, and the quality of the resulting bathymetry. The raw imagery had no blanks or empty patches, and the instruments were well calibrated, which prevented any shifting or warping of the data.

Our team faced three challenges on this expedition: 1) crazy flights, 2) integration and setup of our multibeam bathymetry survey skid, and 3) executing the water- and gas-tight sampling:

1) Our team’s journey from Victoria, Canada, to our port city, Mauritius (southeast of Africa) was an adventure, to say the least! What is normally a leisurely 40(!)-h. trip became a long-lasting series of obstacles. Our first flight out of Victoria was an hour late, so we likely would have missed all our upcoming connections. We were able to catch earlier flights, but then… as we approached Dubai, we found out that the airport was closed due to severe flooding (1.5 years’ rain in one day) and we diverted to Bahrain, an entirely different country where Air Canada had no facilities or services. We now joined thousands of people who were stranded in the area. Keith Tamburri asked the local airline, Emirates, if there was an earlier flight from Bahrain to Dubai and found a pay-by-hour hotel in the airport so that our team could lie down. We ended up catching an early morning flight out of Bahrain to Mauritius. When we landed in Bahrain, we were allowed to exit and stay in the airport, but our luggage remained locked in the plane. Air Canada tried to reschedule our flight for two days later from Dubai to Mauritius, but then we would have arrived after the R/V Isabu was scheduled to leave. So, we finally caught an earlier flight for that evening and made it to Mauritius a day late. At this point, it had been 72 hours or more of travel, and we needed to try to file lost baggage claims. We knew we wouldn’t have our bags for days and were hoping that they would arrive before the ship sailed. Our bags ended up arriving at our hotel the day that the vessel LEFT — we just missed them. So, we had to buy new personal items but didn’t duplicate anything that we already had. In the end, the R/V Isabu still left on time, but we didn’t get our bags until the expedition was completed. We are grateful for our travel agent, who really supported us here!

2) The second challenge was the installation, integration and setup of the survey skid for multibeam bathymetry. Our team used the R/V Isabu’s navigation system and integrated several pieces of rental survey gear, which made it difficult to operate, as opposed to working with just one piece of gear. Barry Brake (Manager, IT and Navigation), Will Glatt, and Keith Tamburri (Operations Manager) worked several long days to get the equipment as planned, calling technical support in Houston, Singapore, and the UK. They managed to get a patch test (calibration) completed and started a survey, but there were still a couple of bugs in the system. So, they decided to reboot it in 6–7 h. The science and ROPOS Team’s original plan was to switch back and forth between gas sampling and multibeam bathymetric surveys at every site. Our team put ROPOS into sampling mode and decided to stay in sampling mode at every site. Once sampling was complete, we would do a survey. Keith Tamburri said that he would have preferred at the beginning go into one mode and stay in it for all sites, then go into another mode and stay in it for all sites. Despite the challenges, we were able to successfully collect high-quality multibeam bathymetry using this method!

3) The third challenge was the gas sampling. It’s common to leave the samples on the ship for gas extraction later. ‘Gas tights and majors’ are types of samples where you are bringing water and gas samples up in the exact condition that they are in at depth. The deep sea is a high-pressure environment, so this was essentially like bringing a bomb onto the ship. Gas expands, so the valve must be released to vent it, or the sampler will explode. Dave, Tamara, and Marve had a huge, elaborate offshore chemistry setup that looked like a wall of valves, tubing, and propane torches that was designed to remove the gas from the samplers while onboard the ship and to preserve the integrity of the samples. In the end, our team was able to safely handle the samplers and deliver the high-quality samples that were expected!