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Conducting science

New rules proposed for entering ice caves on Mount Erebus

There are few places in Antarctica that have been studied as long as Mount Erebus, with continuous research atop of the active volcano stretching across four decades. But one of its most mysterious phenomena — ice caves created by the volcano’s steam, like giant blue-white irregular baubles of blown glass — is only recently drawing attention by scientists.

That interest has necessitated the creation of a “code of conduct” to ensure that the scientific values represented by the ice caves, from biological to geological, are protected, according to officials with the National Science Foundation’s Office of Polar Programs (NSF OPP).

“They’re one of the more vulnerable areas because they have warmer soil temperatures, which means they can be more easily harmed by more temperate plants and microbes,” explained Adrian Dahood, environmental policy specialist at NSF OPP, which manages the U.S. Antarctic Program (USAP).

Research on the 3,794-meter-high volcano near McMurdo Station has naturally focused on volcanology and related disciplines since the discovery in 1972 of Erebus’ active lava lake. Led by Phil Kyle, a professor at New Mexico Tech, scientists have studied everything from the explosive phonolite lava to the noxious cocktail of gases that the volcano continuously spews.

Gas and steam also escape from the flanks of the volcano through fissures called fumaroles. PhD student Aaron Curtis at NMT, who has made the ice caves the focus of his thesis work, has found that the steam-carved structures play an important role in how gas and heat escape from Erebus.

“The caves are really controlled by these discrete gas vents. That really changes the model for how the caves are developed and how they relate to the volcano and the plumbing system of the volcano,” he explained.

The microclimates within the caves are far different from what’s generally found around Erebus, where surface conditions average nearly minus 33 degrees Celsius with little humidity. Inside the caves, temperatures are typically around 0C with relative humidities up to 100 percent. Levels of carbon dioxide are also unusually high, leading Curtis and colleagues to believe that the degassing of CO2 occurs mainly at the cave vents.

It’s in these dark and wet environments where Hubert Staudigel hopes to learn more about how microorganisms exist in such extreme conditions to understand how early life evolved inside volcanoes and in the early Earth.

“We can practically go inside a volcano through these ice caves, into the dark environment where life has to survive in the absence of light,” said Staudigel, a research geologist at Scripps Institution of Oceanography and principal investigator on a five-year project to study extremophiles in Antarctica. “We’re in a pristine environment, and that’s where we want to explore extreme life.”

Except some of the caves aren’t that pristine, as Laurie Connell from the University of Maine in Orono found out by studying the genetic fingerprints of microbial communities from some of the caves.

Research and visits by mountaineers has naturally led to human contamination, particularly around caves closest to the field camp known as Lower Erebus Hut. Something as seemingly innocuous as food crumbs accidentally dropped in a cave or smoking in the protection of an ice cave may have an impact, according to Dahood.

“People have just been doing research and doing whatever they wanted to do, so now we’re restricting activity until we can put in place a formal code of conduct,” she said.

The United States presented a white paper to the Antarctic Treaty Consultative Meeting (ATCM) held earlier this year in Hobart, Australia, that urged that a code of conduct be developed to help manage human impact to the cave system on Erebus.

In the interim, the NSF recently approved a temporary moratorium on visits to all ice caves unless for scientific research, and is temporarily restricting access to pristine caves except for purposes of collecting data on microbial communities. In those cases, scientists must use clean-access protocols, such as wearing Tyvek suits inside the ice caves.

“I think it’s great we’re finally having this conversation. It’s something that should have happened 30 years ago when the caves were first entered, and is especially important now with all of the attention the caves are getting,” Curtis said, referring to a series of high-profile media stories, including a feature this summer in National Geographic magazine about Mount Erebus.

The paper submitted to the nations that oversee management of the southern continent through the Antarctic Treaty System also recommended generating an inventory of the ice caves, something Curtis has already undertaken.

A database that he is developing contains information on about 120 ice caves, compiled from his own explorations and those of colleagues like Nelia Dunbar and William McIntosh, both of NMT, who have worked on Erebus for decades. Curtis’ research involves understanding how the ice caves and towers form, and mapping out their structure, a task he has worked on for the last three Antarctic seasons.

He estimates there are probably another 100 ice caves that no one has yet visited or mapped. An inventory should include a record of every visit and the activities that took place, according to Curtis.

“In order to do good science, you need to know what happened before in the caves,” he said. “Having a really good shared dataset is the most important thing.”

A small area on the northwest slope of the main crater called Tramway Ridge is already safeguarded as an Antarctic Specially Protected Area (ASPA) under the Antarctic Treaty System. A permit is required to enter an ASPA, which provides guidelines on what activities are allowed where in the protected area.

In the case of Tramway Ridge, located at about 3,400 meters elevation, the area has significant gas emission and its soil has the highest surface temperatures on Mount Erebus. The micro-ecosystem includes an unidentified moss species, as well as a wide variety of thermally tolerant bacteria.

A six-square kilometer area on Mount Melbourne, about 400 kilometers north of Mount Erebus, is also designated as an ASPA. The warmest areas of ground on Mount Melbourne created by fumaroles support patches of moss, liverwort and algae, along with one species of invertebrate protozoan, or complex single-celled organisms. A third similar site on Mount Rittman, even farther north, is not yet protected.

Dahood said the United States is working with New Zealand to develop a new ASPA that would fold all three high-altitude geothermal areas into a single, more comprehensive management plan. Particular concern exists because the warmer soils in these areas are inviting to temperate microorganisms that could hitch a ride with a visitor to the area.

“They’re not really well represented in the ASPA system,” Dahood said of the geothermal areas.

Staudigel said he believes it may not be necessary to formally incorporate the ice caves into an ASPA. He and Curtis will work together this season on Mount Erebus to continue an inventory of the caves and discuss a permanent access and code of contact solution that will be satisfactory for all involved.

“Such a code of conduct will have to address issues of access to the caves, the biological cleanliness of equipment and scientists, as well as the minimal impact of activities in these caves,” Staudigel said. “Points of discussions include the cleanliness of instruments, special protection of high temperature zones within the caves and activities such as eating and drinking.

“Biologists and geologists need to be on the same page for the conduct of research in such fragile environments,” he added.

Curtis agreed, though he added that it is important for people working in caves of such a high-altitude environment to remain fueled with food and to stay hydrated.

“We need to protect the caves; we also need to protect the cavers,” he said.

The interim code of conduct approved by NSF for the 2012-13 field season restricts activities such as eating and drinking to the cave entrances. It also requires sterilization of instruments that are used in the vents or warm soils, and it prohibits leaving any gear or equipment inside the caves.

“Ultimately, all parties involved are working toward a compromise code of conduct that maintains the microbial integrity of these fascinating ecological settings while also allowing for the important measurements that need to be made to understand the outgassing of Mount Erebus,” Staudigel said.

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Curator: Michael Lucibella, Antarctic Support Contract | NSF Official: Peter West, Division of Polar Programs