The main message for today's update is an overwhelming thank you to the crew of the R/V Thompson and the ROV ROPOS team for their hard work, patience with evolving daily plans as we worked hard to adjust to weather and operational schedules, and for their engagement with the students. We are ~ 60-days into this 83-day expedition and we very much appreciate their contribution to the successes we have had so far.
Today is a much quieter day onboard compared to the intense 24/7 activity that has characterized the past 18 days of Leg 4. As with the previous Legs, this one was highly successful. It saw the complete installation of the Southern Hydrate Ridge Site, the completion of the Endurance (EA) Offshore Site, and near completion of the EA Shelf Site. Thirty ROPOS dives occurred during this Leg. Both the 10-km and 17-km extension cables were installed by the cable ship Dependable and powered up – they are working.
With much tenacity, the APL engineers, UW-OSU Science Team, and ROPOS group, completed the state-of-the-art, Shallow Profiler mooring installation at the EA Oregon Offshore site with deployment of the instrumented winched profiler and the instrumented platform assembly onto the 13-ft-across platform located at 197-m water depth. The ROV installation included some complex operations, which the ROPOS team made look effortless.
At Southern Hydrate Ridge, three junction boxes, three short-period seismometers, a broadband seismometer and mass spectrometer, a digital-still camera, two fluid-flow meters, an acoustic doppler current profiler, and fluid sampler were installed and cabled. We also documented astounding changes in the "face" of the active methane seep called Einstein's Grotto that sporadically emits large bubble plumes. Nearby, we got stunning imagery of an amazing snail field hosting Neptunea snails that build beautiful yellow stalks of eggs. The most astounding discovery was that of exposed methane hydrate on the seafloor for the first time at SHR – a large boulder of translucent methane ice was found within a collapse pit adjacent to an intense bubble plume!
The nine students participating in the College of the Environment, School of Oceanography Ocean 411 class this Leg, were dedicated loggers, documenting all aspects of ROPOS operations, taking digital-still images, and helping with metadata. Their diligence to details paid off with the potential discovery/documentation of a "weird" fish not seen since the 1970's – a voracious predator. Their projects spanned short video documentaries about methane hydrates, ROPOS, the two-legged moorings, and a fluid-flow meter, to creating code to analyze current data coming off one of the OOI sensors so that we can more easily test this instrument. Three students have assembled images and high-quality videos documenting every major animal at SHR, as well as others observed at the Slope Base and Oregon Offshore site. These will be a great resource for follow-on investigators and educators interested in marine biology. The students presented their work/findings to the Science Party and members of the ship crew on the way into port.
Our work is not done, however, and we are already looking towards the next two legs. Today, two very large winches were lifted onboard, which will be used to install two more Shallow Profiler Moorings at the base of the continental margine (Slope Base Site) and at the base of Axial Seamount (Axial Base) at water depths of 9000 feet. New crew and students will arrive tomorrow. Onward we go towards completion of the cabled component of NSF's Ocean Observatories Initiative.