Do Asphalt-Loving Microbes Point the Way to Life on Titan?
Trinidad, the larger island of the Caribbean duo Trinidad and Tobago, is home to Pitch Lake. This 100-acre pool of hot liquid asphalt is the largest of its kind on our planet, but microbiologist Steven Hallam thought it could tell us something about another world: the Saturnian moon of Titan. If anything could live in the toxic stew of Lake Pitch, he thought, perhaps there’s hope for the hydrocarbon lakes and rivers of that distant moon. He found that the earthly lake teems with life. “Water is scarce in the lake and certainly below the levels normally thought of as a threshold for life to exist,” he says. “Yet on average, each gram of ‘goo’ in the lake contains tens of millions of living cells” [Australian Broadcasting Corporation].
As you might imagine, studying samples of an asphalt lake is, well, unpleasant. The molasses-like goop got all over the lab, Hallam says, and because oil and water don’t mix, water couldn’t wash it off. “It’s somewhat nasty,” says astrobiologist Dirk Schulze-Makuch of Washington State University in Pullman, who led the field study. If the thick gunk gets on your clothes, he says, you might as well just toss them out [Science News]. Yet the team slogged through it, and submitted the findings to the journal Astrobiology. The researchers say that 30 percent of the organisms they found in Lake Pitch were previously unknown.
However, not all the mysteries around these microbes have been solved. The issue of unexpectedly low water activity still remains a question mark, Schulze-Makuch acknowledges. It is possible that the organisms whose genetic material they recovered could inhabit tiny reservoirs of water trapped in the asphalt samples [Christian Science Monitor]. For some scientists, then, the Lake Pitch inhabitants may not have as much to say about Titan as Hallam hopes. If the organisms feed on the hydrocarbons but live in tiny amounts of water, that would appear to be a much different situation than hypothetical life on Titan. There, presumably, life would have no water in which to reside.
Image: Dirk Schulze-Makuch,Washington State University