Still, the thousands of years of history collected in the ice cores almost melted away on the voyage home, when huge waves knocked out power to the freezer and swamped a backup generator. It was 36 hours before a technician could get on deck and restore power. But the ice stayed cold enough and reached the project’s base in Wellington, the New Zealand capital, last month.
The cores consist of sandwich-like layers of ice, formed when annual snowfall compacts to a fraction of its original depth. Bertler said she believes most of the ice she has collected is less than 40,000 years old, although the final pieces near the rock bottom could be up to 150,000 years old.
The material Bertler thinks may be marine sediment came from 760 meters (2,500 feet) deep.
Richard Levy, a New Zealand scientist who specializes in past climates and who was not involved in Bertler’s research, said the project provides a high level of detail about climate change over relatively short periods of time.
The layers of ice allow scientists to measure atmospheric gas levels on an almost annual basis going back thousands of years, he said. That complements rock-drilling work Levy and others have done in the Antarctic interior, which tracks climate change over longer time horizons of several million years, he said.
Bertler’s project has taken about seven years to complete and cost about 11 million New Zealand dollars ($9.2 million), most of which has come from the New Zealand government. Scientists from Australia, Britain, China, Denmark, Germany, Italy, Sweden and the U.S. also are involved.
Tim Naish, a colleague of Bertler’s who heads New Zealand’s Antarctic Research Centre, said that if Bertler has indeed found recent marine sediment, it could be significant.
‘‘It will provide insight into what happens when the Earth warms,’’ he said.
McGuirk reported from Scott Base, Antarctica.