Is Lake Vostok, buried in the Antarctic, bustling with life?
Scientists found 3,507 unique gene sequences in ice drilled from Lake Vostok, the world's largest subglacial lake.
(Page 2 of 2)
The other half of the sequenced material from the ice did not match any sequences in the public database. Rogers told the Monitor that this material could be viruses, an area in which the database has little information. Altogether, though, those unaccounted sequences are suggestive of our world's apparent infinite capacity to surprise us, he said.Skip to next paragraph
In Pictures Antarctica: Landscape of ice
Subscribe Today to the Monitor
“Even though there’s a very large number of sequences in the gene bank, it’s still likely less than half a percent of what’s out there,” said Rogers. “It’s an indication of how much scientists still don’t know.”
The suggestion that life could exist in remote and buried Lake Vostok is controversial. The drills that have been sent spinning down into the lake since its discovery in the 1960s have potentially contaminated the ice with kerosene and other nonnative materials, possibly adding a deceptive wealth of bacteria to an otherwise barren, or at least less populous, ice sheet. Studies that have originated from Lake Vostok samples have historically been plagued with doubt and suspicion, especially since proving contamination, or its absence, is difficult.
And some scientists have expressed concern about the sample used in the latest experiment, drilled from the bottom of the lake’s ice sheet in 1998. Contamination could account for the volume and complexity of organisms sequenced from the ice.
“The analyses used accreted ice samples whose integrity has been questioned in the past,” said Mahlon Kennicutt II, a professor of oceanography at Texas A&M University, in an e-mail interview. “The retrieval of theses samples was not designed for the purpose the accreted ice is now being used for, raising questions about the introduction of non-indigenous organisms during retrieval, on site sampling, and transport to the laboratory.”
“Unfortunately, once the integrity of the samples is called into question, the results will always be suspect, so these results need to be taken with caution and some skepticism,” he said.
The scientists acknowledge in their paper the dubious record of samples drilled from Lake Vostok, but also say that high-tech steps were taken during the experiment to eliminate contamination.
“Contamination is always an issue. Putting your fingerprint on the ice could introduce more organisms than are actually in the ice itself,” said Rogers. “But I think we’ve controlled for all those possibilities.”
Another controversial point is whether or not there are even more complex organisms in that ice-harbored world. About half a dozen of the bacteria found in the ice are closely associated with fish – so, against all odds, are there fish down there?
"On a scientific basis it is hard to see how [Lake Vostok] is 'teeming with life' – even multi-cellular life, when there is little evidence that the Lake has the requisite energy, nutrients, and/or carbon sources to support such an ecosystem," said Dr. Kennicutt. "Speculating about higher organisms in the lake is fanciful at best and not in sync with our current understanding of the biogeochemical setting of the lake."
Still, other scientists have expressed optimism that fish could survive sealed beneath the ice.
"Until relatively recently the Antarctic continent was farther north with a temperate to tropical climate, so it is highly likely that lots of biota was present as the continent cooled and moved south by processes of plate tectonics," said James Haynes, a professor in the department of environmental science and biology at SUNY Brockport. "The 20+ million years between lake formation and complete ice cover provided a huge amount of time for species to adapt to colder conditions, possibly including living permanently under ice."
He cautioned, however, that there are still serious questions about what exactly the conditions are like beneath the ice and, once that is known, how that life would have adapted to the unusual environment. Only directly sampling the lake water could prove the existence of living fish there, he said.
Rogers, too, is hopeful that fish might be found in Lake Vostok.
"Animal physiologists might say it's impossible for fish to be alive in that lake – but I believe it's possible," said Rogers.