Being at sea on the 2024 Regional Cabled Array cruise must be in an ocean warped in time. Although we have only been at sea for three days, it feels much longer – not in a bad way just distorted. Perhaps due to the fast pace of this cruise, and both the ever changing environmental conditions and operational schedule that we keep, many of us have lost track of what day it is and work completed even 48 hrs ago seems like weeks.
Day 1 August 27th: Our journey started three days ago leaving the NOAA dock in Newport, Oregon under blue skies and sea state conditions that made our four-hour transit to the Oregon Offshore site mostly comfortable. During the transit, the newcomers to Leg 3 got the joyful experience of donning their immersion suits, or ‘gumby suits’ for the first time. TC the SSSG, and Andrew, the First Mate on the Atlantis, gave an excellent safety review and Andrew the best gumby suit drill us old timers have seen.
We watched as new folks struggled to get into their suits, including placing a tight flap over their face so only their eyes were exposed. As Andrew said, this is an important step to help keep body heat in and as much water as possible out. He also had all the participants cluster in a joined circle while he spoke to them about, if they were ever in the ocean, the circle would help keep the inner area calmer, and by being joined they would also be a bit warmer. Although the suits are critical for survival if you are ever in the ocean, they are very cumbersome and hot inside. The students were glad to be free of them once the drill was over.
We arrived at the Oregon Offshore site on time and with a Deep Profiler instrumented vehicle safely secured on the front of Jason in a ‘clam shell’ frame. These highly productive waters (only about 40 miles offshore of Newport) support a diverse water column and seafloor community. As Jason transited through the photosynthetic zone, filled with soft light from the sun, into the dark and colder waters of the deep, huge clouds of jellies and ctenophores (comb jellies) gently floated by, feeding…and marine snow was abundant.
Jason attached the new profiler vehicle to the top of the moorings’ float and cleaned a significant portion of the cable covered in marine organisms. As Jason worked near the bottom of the mooring at the docking station (~580 m), which charges batteries in the Deep Profiler vehicle and allows downloading of data, a sable fish, likely foraging on biological material stirred up by the vehicle, passed by.
In past dives, we commonly encounter huge schools of sablefish (black cod) that swirl around and on top of the OOI-RCA equipment or settle in depressions in the sediment; as the ROV works on the seafloor and stirs up sediment, the schools get even denser – occasionally blocking our view and interrupting operations. Flashing comb jelly fish and other jellies floated gently by the mooring. Jason returned to the Atlantis with the 2023 vehicle safely stored in the clam shell.
Turning of the Deep Profiler vehicle completed this years’ work on the Cascadia Margin: the Atlantis headed west to our dear friend Axial Seamount watched over by Vulcan.
Day 2 August 28th: In the wee hours of the morning, the weather gods sent us angry seas and strong winds. Indeed, occasionally a large bang sent us looking up from our work as the seas strongly slapped the hull of the ship. The transit speed was slowed to 6 knts, lessening the pounding of the waves and keeping the ride smoother. However, that did not stop some team members whose berths were forward and on the deck below the bridge from “dancing across the cabin floors” and hanging onto railings in the shower so we and the shower curtain stayed in place. You rapidly learn not to be standing up while putting underwear or pants on! The team used the day to catch up on sleep, report writing and readying and testing equipment for the upcoming dives at the base of Axial Seamount. With anticipation to begin work at Axial Base, the Atlantis arrived late in the evening and the team was eager to conduct the dives. But, Poseidon had different plans for us as the seas were too angry to dive in: we were on weather hold until daylight when visibility would improve.
Day 3 August 29th: The morning daylight brought good fortune and Jason was able to dive at the base of Axial Seamount with the Deep Profiler vehicle attached to the front of Jason. The team was well rested and happy to be working again. With lower biological productivity, here the shallow waters are beautiful blue in color. As Jason approached the float at the top of the mooring, it was met by a school of small fish in crystal clear water. At the base of the mooring (2600 m water depth), venus fly traps colonized the anchor, keeping company with a pom pom anemone on the surrounding sediment.
The next task was to recover a Science Pod from the Shallow Profiler Mooring at 200 m water depth because the controller inside the pod needed replaced. The pilots did a phenomenal job and within 1 hour the vehicle was back on deck with the Science Pod attached under the vehicle.
Once on deck the APL engineers, formed a highly coordinated team and within only a couple hours all the cables from the eight instruments on the pod were disconnected from the canister hosting the “brains” of the vehicle, the crane had lifted out the controller titanium housing and replaced it with the new one, and all cabling was reconnected. Time is a very valuable commodity out here, so while the engineers worked to repair the Science Pod, Jason dove again to 2600 m with a tripod that measures temperature, depth, conductivity, dissolved oxygen, and how turbid the deep, cold ocean waters are. This dive, at 8500 feet beneath the oceans surface, took several hours to finish. Work at Axial Base was completed in the early morning hours of August 30th, as Jason returned the repaired Shallow Profiler Pod back to its home on the 200 m deep platform and ~ 0800 in the morning Jason began a short transit to the summit of the volcano.
For the next several days, the RCA team is looking forward to working at in the caldera of Axial Seamount. Through the many eyes of Jason, will be seeing/experiencing spectacular lava covered landscapes with large collapse basins that were once filled lava lakes, rock arches and columns formed during draining of the lakes, and some of the most amazing life forms on Earth thriving on metal sulfide monoliths emitting boiling fluids at 350°C. Each year we look forward to visiting the vent fields and witnessing the changes that have taken place since our last visits.