Fire and Ice
Scientists explore mysteries hidden beneath the water
University of Hawaiʻ faculty work in some pretty remote environments. Summer 2005 took scientists to two extremes—south to volcanoes in the Pacific’s Ring of Fire and north to the Arctic ice.
In both cases, scientists worked underwater, either remotely (mapping with a sonar tow fish or monitoring and sampling with a robotic vehicle) or in manned mini-subs. Their work expands our knowledge of animal life and geologic processes hidden by the ocean’s depths.
South to the Ring of Fire
Boiling water jets like flames, the bubbles compressed by high pressure in deep water
Some things you can’t know unless you look directly, says Rachel Shackelford Orange, her excitement palpable even though she experiences ocean dives vicariously as she compiles Hawaiʻi Undersea Research Laboratory images and data.
Consider site V-18s: dredging hadn’t identified the predominance of pumice because water swept the lightweight material from earlier ship-drawn samples. And underwater volcanoes aren’t all the same. Flat four years ago, Vailuluʻu Crater off Samoa has a new cone 300 meters high and growing about 8 inches a day. The Kermadec Arc closer to New Zealand revealed sulfur seeps on a sandy bottom that melted the sub’s sample basket, sheets of iron oxides, fields of dead mussels and huge sulfur deposits with chimney formations called white and black smokers. A chimney knocked down for sampling was rapidly reforming within a day.
A five-month, $4 million cruise
HURL conducted nearly a hundred dives at the 41 sites between Hawaiʻi and New Zealand visited by UH’s's R/V Kaʻimikai-o-Kanaloa.
Crews rose at 5 a.m. for pre-dive activities, dives by the manned submersibles Pisces-V and Pisces-IV and the remotely operated vehicle (ROV) RCV-150, post-dive operations and prepping for the next day before hitting the sack around 10 p.m. Video and still images were sent to UH Mānoa for archiving and analysis during port calls.
The ship had calm weather for the most part, but also rode out some rough storms—once called to the aid of another vessel. The crew got so good at launching the underwater vehicles that they conducted dives in conditions that would have stymied other cruises.
Good dynamics is important when you live in close quarters
Unexpected views, like a dense population of crabs not usually seen on underwater volcanoes, bring pleasure to the long hours and hard work of exploring. Colleagues say the HURL team—25-year veteran Terry Kerby and fellow Pisces pilot Max Cremer, support technicians Colin Wollerman, Steven Price and Douglas Bloedorn and ROV engineers Dan Greeson and Peter Townsend—work effectively because they know their stuff and love what they do.
Using two subs allowed dives in one while the other underwent maintenance and repairs. It also created a safety net, providing a backup vehicle should rescue be required. In unknown or difficult conditions, the subs carry two pilots and a science observer; on more routine dives, the co-pilot gives up his seat to a scientist. Among the eager takers: researchers from HURL, other U.S. institutions and agencies, Germany, New Zealand and Australia.
Nearly every dive brought surprises, both geological and zoological
Monowai had hydrothermal biota not seen at Lōʻihi. Rumble 5 had elongated urchins. Clark’s huge twin towers were surrounded by barnacle fields, and its cone had coral growing on one side and thermal vents on the other.
At the relatively shallow V-1, huge groupers appeared, like curious cats, to examine the sub and bubbles swept through mussel beds, visible in the ambient light. Sampling revealed more than two dozen new species of bacteria living in the extreme conditions around underwater volcanoes.
Scientists are also analyzing data about other marine life, chemistry and mineral formation. The cruise included non-volcanic dives as well—mapping habitat, collecting samples to gauge climate variability, analyzing the ecological impact of a grounded vessel and conducting marine archaeology in the remote atolls of the eastern Samoan chain and U.S. Line Islands of the central Pacific, including Palmyra Atoll.
North to the Arctic ice
A cold snap can claim instruments, so the decision to deploy isn’t made lightly
To build underwater mapping equipment for Arctic research, Margo Edwards and her Hawaiʻi Mapping Research Group had to consider how sonar would behave under low temperatures, high pressures and salinity.
First used in 1999, the mapping equipment displayed what appears to be deep ice gouges caused by the movement of an ice shelf hundreds of meters thick across the Alaska continental margin. Edwards was eager for confirmation, but conditions on the USCGC Healy’s first leg (which included four days stuck in ice) largely thwarted mapping.
Still, other scientific observation and sampling took place. Later legs benefited from the progressing summer thaw—on the second, students mapped the seafloor in support of zoological work; the third saw the team "working like dogs" mapping, coring and sampling as the cutter traversed the North Pole to Norway.
You don’t get seasick on an icebreaker; all that ice keeps the ocean flat.
You don’t get much sleep either. The 420-foot Healy works by powering forward onto the ice. If its weight doesn’t break through, it backs off, dragging across the bumpy ice with a sound like bulldozers outside your bedroom.
Choosing the route of least resistance creates a zigzag of slush behind the ship, but the solid white surface to the side is a bit disconcerting to those used to seeing water when they’re at sea. The Arctic summer sky has the perpetual appearance of 4 p.m. regardless of the time. "Shore" leave onto the ice for recreation, ice coring and brief dives beneath the ice are tinged with the constant awareness of cordoned off thin spots and the watchful sentry armed with a shotgun because polar bears are not hospitable hosts.
The cruise married geology with oceanography
An interdisciplinary approach allows scientists to study not just how the seafloor looks, but how it influences the physical and chemical ocean environment. Geologists cored, analyzed and preserved samples of the ice and the seafloor while zoologists identified creatures like tiny, colorful, shrimp-like Hymenodora glacialis and non-stinging comb jellies brought up in water samples or captured by divers.
Inside, mappers hunched over computer screens to decipher what the sonar mounted on the Healy’s hull unveiled. As often as once a day, someone would call "what’s this?" and everyone would ran over to interpret and argue.
Methane seeps, evidence of landslides and dragged boulders, an underwater volcano just when you thought everything was flat and boring ... "It’s exciting," Edwards says. "We haven’t looked at 70 percent of our planet because it’s underwater." But it could happen in her young sons’ lifetime, she muses.
Edwards admits she was skeptical about global warming
So what if temperatures are up 1 degree since 1890—thermometers then weren’t the precise instruments scientists have now, she thought.
Then she saw evidence from every branch of science: polar bears 40 pounds skinnier than they used to be and less apt to have twin cubs; tree lines shifting 100 miles northward; birds dying and new species moving in; coastlines eroding. "I’m not a skeptic anymore," she says.
Scientists know the shrinking extent of the ice sheet, but they don’t know its mass. The mapping team proposes turning sonar on its head, creating an upward-scanning instrument for testing in 2006 and deployment in 2007 to map the underside of the ice canopy, producing more accurate calculations of the amount of ice.
There’s also potential—and reason—to map most of the country’s coastal areas. For example, looking at the seafloor can help explain what is dragged where in a storm like hurricane Katrina, she explains.