From Volcanoes, to Full Ocean Depths to Methane Seeps

Tuesday, July 14, 2015
Profiling the Ocean
ROPOS Control Room at El Guapo

The ROPOS control room onboard the R/V Thompson as it works at the 18 m tall (59 ft) actively venting chimney called El Guapo in the International District Hydrothermal Field. Credit: Mitch Elend, University of Washington, V15.

Over the past few days, we have traversed some of the most extreme environments on Earth. Yesterday, we left Axial Seamount after finishing work at 280°C hydrothermal vents teaming with novel life. From there, ROPOS documented for the first time the state-of-the-art shallow winched profiler migrating up and down through the water column from the 12 ft-across platform 600 ft beneath the ocean’s surface. Over the past year, the platform has turned into a “reef” marked by a small school of fish that swarm around the cameras and instruments. One fish was getting a “belly rub” as the cable on the drum of the winched profiler was turning. ROPOS carefully drove around the mooring to document the movement of the shallow winched profiler as it moved through the water column taking hundreds of biological, chemical and physical measurements of the ocean waters at high resolution. During this operation, the scientists and engineers on the ship were in direct contact with APL engineer Eric McRae who operated the profiler onshore from >300 miles away. Communications traveling at the speed of light from the UW, allowed almost instantaneous control-response of the shallow profiler, telling it to rise 6 feet, go back into the dock, rise 100 feet, take samples etc. ROPOS again, waved at the digital still camera on the mooring as it took picture of ROPOS and the surrounding fish. It was a remarkable orchestrated dance to watch and we look forward to seeing in the fall the amazing science data that the diverse array of instruments on this mooring will transmit in real-time to shore. During the evening, Orest Kawka directed several CTD casts from 8858 ft to 300 ft beneath the ocean’s surface. At depth, all is entrained in darkness, while at shallow depths diffuse light from the sun filters through the water.

Late last night, upon completion of the water column work, the R/V Thompson turned east – we were graced by a beautiful, awe inspiring sunset as we began the 16 hour transit to Southern Hydrate Ridge. Now, the ROV ROPOS is diving in another extreme environment – an active methane seep where bubbles of methane burst from the seafloor. Here, we see hummocky topography marked by extensive white bacterial mats, rock and hag fish, and large clams hosting chemosynthetic, symbiotic bacteria in their guts supported by the methane and hydrogen sulfide seeping from the seafloor. We will continue to work at this site through tomorrow – lead APL engineer Skip Denny is continuing to keep a keen eye on the weather during these operations.