Research Vessel Thomas G. Thompson at sea. Credit: UW
The Tommy Thompson, as it’s affectionately known, is heading back to Newport, Oregon to get ready for the next and final leg of this summer’s construction project for the regional cabled observatory. If all goes as planned, by mid-August they’ll have installed all the observatory’s secondary subnets at the Axial volcano and tested the cables and instruments, including an HD video camera. But, as chief scientist John Delaney says, with oceangoing research, plans are just the starting point. Weather, equipment failures, and occasional human error all factor into a continually evolving set of activities, more like jazz improvisation than a symphony orchestra.
This leg started with some setbacks, from a lost day at port fixing an electrical problem with the ship’s thrusters to being blown out on the first dive by ocean swells at the continental Slope Base. Once we got to Axial though, the team got into a rhythm of laying and testing cable, installing instruments and collecting data, the latter of which provided perhaps the expedition’s most joyous moment when two seismometers detected and recorded an earthquake. On the same 36-hour epic dive, however, we all learned a new term, “hockle.” A hockle is a kink in the electro-optical cable and a few of them were discovered in a cable, which testing showed had restricted its ability to carry data and power. The engineers will do more testing on the next leg and may need to replace some of the damaged cable. Despite those hiccups, the observatory construction work ended on a high note with a successful cable lay at Slope Base where the sea was almost glassy compared to earlier in the expedition. Throughout the cruise, the deck of the R/V Thompson was cleared of bright orange cable as ROPOS reeled out a total of 16 km on the ocean floor.
Over the last two weeks, the scientists also tried out new instruments including a temperature and salinity probe placed right into an extremely hot hydrothermal vent and a bottom-pressure tilt meter that will measure the movement of magma under the volcano. Co-chief scientist Giora Proskurowski deployed a reinforced collection bottle that can bring up a high-pressure gas sample from a hydrothermal vent for testing in the ship. It was exciting to look over Giora’s shoulder until the moment when he released some of the vent’s sulfurous gas, which immediately filled the room with the stench of rotten eggs. He calls it the smell of success, but I beat a hasty retreat.
The expedition was ahead of schedule going into yesterday, so the team was able to do an oceanographic favor for some colleagues in need (on the order of, “since you’re in the neighborhood…”). John Delaney was asked by geologists at Woods Hole Oceanographic Institute (WHOI) to recover a couple of seismometers that didn’t answer to pings and rise to the surface when signaled. (Underwater instruments commonly have an electronic recovery system that, when activated by a ship signal, engage flotation devices. These two prodigal seismometers, placed in different locations, didn’t come home when called). So we set off to the south on a search and rescue mission to find a couple of lost yellow boxes on the bottom of the ocean.
The dive planners didn’t know exactly where the boxes landed so they devised an ROV search pattern that started close to the sites where each seismometer was dropped. It proved unnecessary with the first yellow box, because ROPOS landed almost on top it and clamped on within five minutes of reaching the bottom. The second seismometer proved more difficult. We steamed to the spot described by the WHOI scientists, but the location had brisk winds and a strong current that made it very difficult for the ship to remain on station above the ROV. After one attempt and some waiting, John Delaney decided it served nobody’s interest to jeopardize ROPOS so we gave up on the second seismometer and started our 15-hour steam back to Newport.
Spending two weeks at sea on a history-making project, which this real-time ocean observatory will surely prove to be, is an incredibly immersive, exhausting and exhilarating experience. Part of my job here was to share the experience and the science I was learning along the way. We did some live ship-to-shore programs with audiences at the Exploratorium, experimenting with ways to activate an exhibit space with a distant research project. In the long term, we hope to find ways to connect the Exploratorium’s Bay Observatory, with its own complement of real-time oceanic and atmospheric sensors, to the regional cabled observatory in ways that would let people explore the data, ask questions and find connections between the deep sea and coastal locations.