A coveted collection of ancient ice cores recently acquired by the University of Alberta has been partially destroyed in an "unprecedented" double malfunction of a $4-million freezer.

Nearly 13 per cent of the samples in the Canadian Ice Core Archive melted when temperatures inside a storage freezer soared to 40 C after the refrigeration chillers shut down, university maintenance officials said Thursday.

After the chillers shut down, the system monitoring the freezer temperatures failed due to "a database corruption," the U of A said in a news release.

The freezer's computer system sent out alarm signals that the temperature was rising but the signals didn't make it to the university's service provider or the on-campus control centre.

"To have two malfunctions of this magnitude at the same time is unprecedented," Andrew Sharman, the university's vice-president of facilities and operations, said in the news release.

"The Canadian Ice Core Archive is a scientific resource of international importance and the University of Alberta takes seriously our responsibility as stewards."

'You lose part of the record'

Martin Sharp, a U of A glaciologist, said in the same release that "an incident of this magnitude is a major disappointment given the investment in the facility and the cost and challenge of replacing the lost samples.

"When you lose part of an ice core, you lose part of the record of past climates, past environments — an archive of the history of our atmosphere. You just don't have easy access to information about those past time periods."

The entire collection, including affected samples, has been secured in a separate freezer with additional safeguards put in place to ensure its integrity, the university said.

"The loss of any ice core sample is deeply disappointing to the University of Alberta and to our research teams, who plan to use this ice to answer important questions about climate change and our planet's history," Sharman said.

"With the assistance of our service provider, the affected freezer has been restored, an investigation is ongoing, and we are working to ensure this does not happen again."

The loss is estimated at 180 metres of ice, or 12.8 per cent of the 1,409-metre collection. The warming did not damage the whole of any core. Each core is stored in multiple one-metre segments.

Melted ice contaminates other samples

The U of A said that once melting occurs, water from one core segment can contaminate others stored nearby. Sharp said that would make it challenging to interpret results of any analyses conducted on contaminated segments.

"This incident will affect research, no question," said Sharp, a professor in the department of earth and atmospheric sciences.

"It rules out certain studies that we might have wanted to conduct on the cores, such as reconstructing continuous long-term histories where parts of the cores have been lost or contaminated.

"But not all research we do involves analysis of entire cores. Sometimes we work with subsets of cores. We may have to reconsider some of the work we planned to do, but the work can and will continue — and nearly 90 per cent of the archive is still intact."

The ice core archive is the world's largest collection of ice core samples from the Canadian Arctic. The collection represents more than 80,000 years of evidence of changes to climate in 1.4 kilometres of ice. The collection contains 12 ice cores that were drilled in five locations.

Detail image of an ice core segment. (University of Alberta/John Ulan) The collection of ice samples, drilled out of the depths of the Arctic over the past 40 years, was carefully transported from Ottawa to Edmonton in January.

They were shipped in a freezer container chilled to -30 C, equipped with a custom-built monitoring system.

The university had built a $4-million facility to keep the ice safely frozen. The ice cores remained in the freezer container until they were moved into the new facility on March 24.

The facility, in the South Academic Building, contains two freezers — a storage unit chilled to -37 C, and an adjacent working unit cooled to -25 C.

Both units were commissioned in October and operated for more than five months while holding 40 five-gallon buckets of ice to simulate the cores. Both freezer units were functioning properly at noon on Friday, March 31.

Temperatures reached 40 C

But late in the afternoon of Sunday, April 2, U of A Protective Services and Edmonton Fire Rescue Services responded to a high-heat alarm in the facility.

Temperatures in the storage freezer had reached 40 C, resulting in the damage to the ice core samples.

"It was more like the changing room at a swimming pool than it was like a freezer," Sharp said at a news conference.

All affected samples were immediately moved into the working freezer, which was functioning properly. Most of the samples were already in the working freezer.

"Most of it was in the working freezer in the first place," Sharp said. "That's the lucky thing about this."

There had been a plan to move the samples from the working freezer to the storage freezer to accommodate a film crew from the TV program Daily Planet.

"We started doing that," Sharp said. "And then their cameraman realized that the light in there was not good from a filming point of view so he asked us to put them in the other freezer, which we did.

"And that's basically what saved us."

Previously housed in Ottawa's Ice Core Research Laboratory at the Geological Survey of Canada, the collection was orphaned due to budget cuts at Natural Resources Canada.

Refrigeration technicians are now monitoring the freezers with twice-daily checks. The computer database corruption has been resolved by adding a second monitoring controller.

More work will be done over the next few weeks to improve the alarm system and to improve the freezer's performance during failures.