Through late last night and the wee morning hours of today, ROPOS worked to stretch out their new umbilical tether that provides power and communications to/from the vehicle. Diving to a depth of 2900 m (~9500 ft) takes about 3 hrs with the heavy junction box latched beneath the vehicle. The transit gave us time to observe significant rain of marine snow in the water column – even at 2900 m. The tether management dive was a success and this morning ROPOS (Dive R1828) dove again to the seafloor with a low power junction box hosting a variety of chemical (dissolved oxygen, salinity), and physical (temperature, seismic activity, electrical fields-water currents, tides, particle distribution) sensors as well as a sensor that can “listen” to mammal calls. The junction box replaced one that had been installed in 2014 as part of the NSF Ocean Observatories Initiative cruise lead by John Delaney.
Today, all students were able to spend time in the ROPOS control room and witness the amazing video system that this vehicle has. They continued to get a feeling for life at sea, the movement of the ship, and they learned how to conduct CTD casts and how to measure oxygen concentrations in seawater. They, as well as the entire scientific team, appreciate the outstanding meals that are being prepared for us by the Thompson's chefs.
The next three dives will involve recovering and reinstalling two instrument packages that go on a large cabled mooring called the Shallow Profiler Mooring. At ~ 600 ft water depth, it hosts a 12 ft-across, 7 ton platform atop a 2700 m (~8600 ft) tall, two legged mooring. It is a state-of-the-art system that allows chemical (e.g. pH, CO2), biological (chlorophyll), and physical (temperature, currents) properties of ocean waters off the Oregon coast to be measured in real-time with live-streaming data sent to shore via the cable.