Busy Days on the RV Thompson

July 17, 2015

Katie Bigham, a junior in the School of Oceanography, takes her first turn at directing ROPOS operations inside the control room. She is studying the distribution of methane seeps and biological communities at Southern Hydrate Ridge. Credti: Ed McNichol, V15.

The Oregon Slope Base Shallow Profiler, engulfed in soft sunlight, rises to ~5 m beneath the ocean’s surface. It is measuring nutrients, dissolved oxygen, seawater acidity, temperature, chlorophyll, and carbon dioxide concentrations at high temporal and spatial resolution, controlled from ~70 miles onshore through the Internet at the University of Washington. Credit: NSF-OOI/UW/CSSF; V15.

Leg 1 of the Cabled Array VISIONS"15 expedition has been extremelly successful with the back deck of the R/V Thompson bulging at the seams with recovered infrastructure and instruments. ROPOS has had rapid turn arounds, pounding out dives. The science crew is tired, but happy. Credit: Mitch Elend, University of Washington, V15.

The R/V Thompson has been a hive of activity the past 24 hrs with dives at the methane seeps at Southern Hydrate Ridge, the recovery of science pods on the Shallow Profilers at the Oregon Endurance Offshore site, a dive at the Shallow Winched Profiler at the Slope Base site, and a dive to 9500 ft beneath the ocean’s surface to recover a transponder instrument that was left there last year.

Brendan Philip, a recent graduate from the School of Oceanography, used the multibeam sonar on the R/V Thompson to image methane bubble plumes rising several hundred meters above the seafloor. The plumes vary at temporal scales of hours, turning on and off, the driving force for the timing unknown, and not well predicted. UW undergraduate, Katie Bigham, took her first turn at directing part of a ROPOS dive at Southern Hydrate Ridge to investigate clam distribution. Here, clams can grow to the size of small gooey ducks. Orest Kawka and UW undergraduate students conducted multiple CTD casts to measure chemical and physical properties of ocean water through the full ocean depths and collected numerous samples. The analytical lab has seen round-the-clock occupancy with both scientists and students working side-by-side to process and analyze the samples for oxygen, pH, methane, hydrogen and hydrogen sulfide onboard the ship, and a full contingent of biological and chemical measurements onshore.

The scale, intensity, and rapid fire of these complex ship and ROV operations requires a fine dance and good communications among the Thompson and ROPOS teams, and the UW science and engineering team. We could not ask for a finer group of people and are grateful to all for their help and support.

With operations nearly complete, our thoughts are progressively moving to Leg 2 of the Cabled Array cruise. As we look forward over the next few days before going to port and into next week, when we will install Deep Profiler moorings down to 9500 ft, Skip Denny, our onboard “weather man” and lead engineer from the Applied Physics Lab is an especially important team member. For those of us who have been at sea a long time, our eyes are always on the weather.His experience is invaluable in guiding us on the timing of operations. He, apparently, requires only 2-4 hours sleep at a time, as he leads most ROPOS dives.