Back At Sea!
by Erik Olsen | March 15, 2018
After nearly five days in Auckland, the Brothers volcano team is finally back at sea. A powerful storm and power problems brought us into port, where we caught up on work and had a chance to see some of the city’s sights. Weather can always be an issue on these trips, and it felt like we’d lost a precious few days. But now it’s time to hunker down and get some science done.
At midnight on Wednesday, the ship slipped out of its berth and steamed northeast out of New Zealand’s largest city and back to Brothers volcano. It takes 18 hours to reach the dive site and after we arrived it wasn’t long before scientists and crew were working hard to get Jason back in the water. There is so much to do!
By 10:00 p.m., Jason had made it to 1,300 meters (4,370 feet), the upper caldera of Brothers volcano. The first order of business was to get back to the thermal blankets we’d placed on the seafloor a about a week ago.
The thermal blankets, which are a special part of this expedition, will help scientists understand how much heat is coming out of the seafloor from the volcano. This is critical knowledge because a second major expedition will return here in May on a large drill ship to collect long cores of rock to help better understand what is going on deep beneath the seafloor. The scientists will use the data from the thermal blankets to locate the best sites to drill because they want to avoid the hottest part of the system.
“It’s a very powerful tool to determine more precisely the amount of heat passing through the volcano into the ocean,” says Cornel de Ronde of the newly developed thermal blankets.
There were five bright orange blankets on the seafloor. The Jason pilot lifted each one with one of the vehicle’s robotic manipulator arms. The plan is to load them onto the seafloor elevator in a few hours and bring them back on board so the scientists can access the data they’ve been collecting over the past week.
There was also a fair amount of exploring to do. Around midnight, Jason was moving slowly around the rim of the upper caldera when we came upon a towering structure, 13 meters (43 feet) high and 1 meter (3 feet) in diameter, that stretched high into the inky depths beyond our LED lights.
“Dead chimney,” said Cornel de Ronde, a co-Principal Investigator of the expedition. We were in an area with once-active hydrothermal vents, where hot, metal-infused fluids rose to the surface and built these magnificent towers. But now they were just ghostly remnants.
“They look like spires on a cathedral,” said de Ronde.
Nearby, we came upon another odd formation that drew gasps from the people watching the live footage from Jason’s cameras, which is broadcast on over a dozen screens inside the “Jason van” (see our recent video tour). The structure looked like something out of a Dr. Seuss story, with ornate edges, and colored in rich hues of green, red, and yellow—indications that a mixture of copper-, zinc-, and arsenic-rich minerals had oxidized there over time.
De Ronde has seen many of these structures in his lifetime exploring underwater volcanoes around the world, but for some of us, it was our first time laying eyes upon something so strange and beautiful.
One of the most important parts of this expedition is to collect samples of water, gas, and rock that lie on or near the volcano. On our first Jason dive, we weren’t able to do any sampling, so it was important that we get started.
At 3:30 a.m., Jason began to gather its first samples. Using a set of “gas tight samplers” the pilot collected fluid coming from the seafloor. When Jason ascends later today, the fluids inside the samplers will stay at the same pressure as the depth at which they were collected. This will prevent any gas dissolved in the fluid from escaping so that scientists on the ship can extract and measure what’s inside using a gas chromatograph.
Around 1:00 p.m., we started collecting actual chimney samples. Jason’s mechanical arms placed pieces into cylindrical containers so they can be brought to the surface. Some of the pieces hold living animals, mostly microbes, that will be brought aboard and studied to give us an idea of the kinds of organisms that grow in these extreme environments.
Jason will return to the surface tonight, bringing with it a bounty of material and data to keep all of the scientists on board busy. “Everybody has something to look forward to, that is the definition of a good dive,” said de Ronde.