Here on earth, life is full of surprises, presenting itself in many different shapes, forms and adaptations. It was once thought that no creatures could survive the harsh combination of high temperatures, toxic chemicals, complete darkness and high pressure of hydrothermal vents on the ocean floor, yet a variety of bizarre organisms, including giant tube worms, thrive there. More than two miles underground, in South African gold mines, various types of worms have been found feeding on bacteria, in complete darkness, with no oxygen, in 120 degree Fahrenheit heat. And recently, scientists have found evidence of life deep under a thick layer of ice in the dark, frigid waters of Lake Whillans in Antarctica. While this is the first time bacteria have been found living in such conditions here on earth, the discovery could also have implications for the search for life beyond our home planet.
The American expedition, led by John C. Priscu of Montana State University, drilled through half a mile of ice and recovered water and sediment samples in which were found cells containing DNA, as well as an enzyme involved in metabolism, and packets of energy made of adenosine triphosphate - all evidence that the bacteria were alive and metabolizing energy. The expedition took meticulous precautions to prevent contamination of the lake by bacteria from external sources or from the overlying ice. Contamination is also unlikely because the concentration of bacterial life was found to be higher in the lake itself than in the borehole. In addition, there were signs of life in the lake bottom’s sediment which would have been sealed off from contamination. At present, the samples are undergoing further DNA analysis to determine what kinds of bacteria these might be.
Meanwhile, a Russian expedition, led by Sergey Bulat of the St. Petersburg Institute of Nuclear Physics, claims to have discovered new forms of life sealed off for 14 million years under a two mile thick layer of ice in Antarctica’s Lake Vostok. According to Bulat, bacterial DNA was found that doesn’t match any known species on earth. However, Vladimir Korolyov, head of the genetics lab where the analysis was done, maintains that most of the bacteria were likely contaminants from kerosene used in the drilling, from human beings or from the laboratory itself. While these results remain controversial, new samples taken this past February from deeper in the borehole, to minimize contamination, are currently en route to St. Petersburg for analysis.
As for the discoveries by the American team, detailed DNA analysis, currently underway, will be key to understanding what kinds of bacteria these are and how they live. As there is no sunlight in the depths of the lake they would have to have an alternate source of energy to survive. This could be organic material that has entered the lake from elsewhere, such as dead microbes from melting glaciers, or minerals derived from nearby rock. According to NASA scientist Chris McKay, it would be of much greater interest if the bacteria are using a local energy source such as minerals from rock because this would have implications for finding life elsewhere in the solar system. Saturn’s moons Titan and Enceladus, as well as Jupiter’s moon, Europa, are considered candidates for extraterrestrial life because they are believed to have oceans of liquid water under thick ice sheets. However, for life to exist there, in the absence of light and oxygen, it would have to depend on minerals alone. If bacteria could be shown to survive in similar conditions, on minerals alone in a dark lake below an ice sheet in Antarctica, it would certainly up the ante to explore these other worlds.
Join the Springfield Stars Club on Tuesday, April 23rd at 7:30pm at the Springfield Science Museum for a talk by meteorite expert, Peter Scherff on “Asteroids, Fireballs, Craters and Other Cool Stuff: Highlights from the Last Six Years in the World of Meteorite Maniacs.” Scherff, an expert at preparing and conserving meteorites, has collected these intriguing objects for 30 years, and gives talks on the subject at schools, colleges, museums and observatories. He consults with museums and universities on their meteorite collections, and has, in recent years, donated a number of meteorite specimens to the Springfield Science Museum. Scherff is a co-proprietor of The Student Prince Cafe in Springfield and an amateur astronomer active in the Arunah Hill Natural Science Center. He hopes to have a sample of the meteorite from the amazing fireball that blazed over Chelyabinsk in February available for viewing at Tuesday’s presentation. Refreshments will be served, and the public is welcome free of charge.
Also, on Friday, May 3rd at 7:30pm the Stars Club and Springfield Science Museum will host “Stars over Springfield,” an astronomy adventure for the whole family. Tim Connolly will speak on “Astronomy Apps on Smart Phones and iPads.” A fee of $3 for adults and $2 for children under 18 will be charged.
Copyright © Amanda Jermyn