The R/V Sikulaq arrived onsite at the base of Axial Seamount just after midnight today under calm seas. During the transit from Seattle, the Cabled Array team worked hard to insure that all instruments and infrastructure were ready for installation and had undergone final testing.
With excitement, the remotely operated vehicle Jason went into the water early in the morning to begin Dive 907. Latched safely under the vehicles belly was junction box LJ03A, hosting a variety of instruments to measure water column properties once installed and connected to the submarine cables. In about 2 hrs, Jason reached the seafloor – greater than 8500 feet beneath the ocean’s surface.
Here, the seafloor is covered in a thick layer of fine sediment, home to numerous brittle stars living in complete darkness. Upon reaching the bottom, Jason conducted numerous tasks that included storing the junction box it was carrying away from the work site, disconnecting wet-mate connectors, and securing previously installed instruments onto the older junction box for safe keeping on their return to the surface.
Once these chores were completed, the new junction box (LJ03A-2016) was moved into place, its extension cable was plugged back in providing it power from shore and communication to and from shore, and a the replacement instruments were installed. These instruments, identical to last years, are replaced annually because they can become fouled by biological colonies and some instruments have pumps that work best when replaced annually. These instruments are providing new insights into the changing salinity and oxygen content of deep ocean waters, temperature, and the detection of currents that flow deep along the base of this large underwater volcano far offshore. To complete the dive, Jason conducted a photo-video survey of the work area, took a water sample using a Niskin bottle mohttp://www.apl.uw.edu/unted on the vehicle, and then transited a couple hours to the surface.
After the instruments were installed, engineers from the Applied Physics Lab onboard the R/V Sikuliaq communicated to APL engineers >300 miles away onshore, letting them know it was ok to turn the instruments on – SUCCESS, they were all sending data back at the speed of light to the terrestrial Internet and onto the OOI Data Portal at Rutgers University.
Hoowever, todays work was not yet complete…..Once Jason was secure on deck, the Sikuliaq transited about 1 km to the next work site above the junction box MJ03A, also at Axial Base, but hosting geophysical instruments. Jason went back into the water at dinner time to again return to the seafloor, this time carrying the junction box MJ03A.
Operations at sea go around the clock – this dive will last until early morning tomorrow. The team is grabbing sleep as they can, rocked gently by the NE Pacific waves….