"These ices are literally gene banks," he added.
That's because bacteria are able to incorporate foreign DNA into their own genetic makeup in a process called horizontal gene transfer. (Get a genetics overview.)
This gives bacteria a way to pick up new advantageous traits, which in turn speeds up their evolution.
Falkowski likens the Antarctic ice to a "genetic popsicle."
As glaciers and ice caps melt as a result of the current trend of global warming, vast amounts of bacterial genetic material might be flushed into the ocean. (See how the ice is vanishing.)
"You basically have this mechanism by which you're freeing up encased DNA and microbes that may be viable," lead author Bidle said.
Scraps of bacterial DNA might get incorporated into today's marine microbes, or viable bacteria released from the ice might also grow and impact the ecosystem. (Related: "Hundreds of Glaciers Melting Faster in Antarctica" [June 6, 2007].)
"How that's going to play out, we don't know," Bidle said. He and Falkowski plan to focus future work on how current ice melting impacts modern microbes' genetic diversity.
The study appears in this week's journal Proceedings of the National Academy of Sciences.
Meaning for Mars?
The finding also lends hope to the possibility that microbes could lie in a similar suspended state in ancient Martian ice. (Related: Photos: Phoenix Lander's Search for Mars Water.)
But it also nixes the idea that life could hitch a ride on comets between solar systems.
"Each solar system is an island of life," Falkowski said. Microbes on comets would be exposed to lethal doses of cosmic radiation for millions of years during their journey, he said.
"Under those conditions you would be sterilizing comets."
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