Saturday, November 3, 2007
Long Live Microbes: Revival of Microbes from Ancient Glacial Ice
A team of scientists from Rutgers University, Korea’s Polar Research Institute, and Boston University has revived microbes from five different samples of ancient ice. The Antarctic samples range in age from 100,000 to 8 million years of age. Antarctica was chosen as a prime site for ice samples because the oldest ice on Earth is located here, in the Transantarctic Mountains. The samples were taken back to the lab and carefully thawed, taking into consideration to maximally avoid contamination by contemporary bacteria in our environment. They did so by soaking the ice samples in an ethanol solution as well as washing the outside of the ice with sterile water. These precautions killed all possible unwanted bacteria.
What do you think they found in the samples of very old ice once it was thawed???? LIVING BACTERIA. How awesome is that???? Both the 100,000 and 8 million year old bacteria could be resurrected from their very cold entombment, however there was a difference between the two. The 100,000-year-old bacteria jumped out of bed like a kid on Christmas morning ready to rip open presents. “The young stuff grew really fast…it doubled every couple of days,” said Kay Bidle, assistant professor of marine biology and coastal sciences at Rutgers; according to their research their was many more microorganisms in the younger ice than in the older ice. The eight million year old ice provided slow growing unidentifiable microbial species. The identification process was impossible because their DNA was so fragmented over years of polar cosmic radiation, that they could no longer repair the damage done. Evidence of exponential decline was also evident from the five ice samples, where “every 1.1 million years, the DNA gets chopped in half,” resulting in very little DNA being left from the 8 million year old sample. Although the old bacteria has very few nucleotide sequences left, and the more recent microbes are rearing to go, they both have genetic material capable of transferring to bacterial species living on Earth today.
Why could this study be such a big deal??? There are two very interesting things this study brings to light, one being the theory that these newly thawed microbes are going to be washed into our oceans at a greater rate than ever, because of global warming and secondly counter acting the theory that bacteria and therefore life landed here via comets from space.
Global warming is a concern on many fronts, however glacial retreat may have a new smaller threat associated with it. The possibility that the ancient bacteria may be able to transfer its DNA remnants to new microbial species in a process called horizontal gene transfer, is a lurking effect on the horizon. As we know from class, this could give microbes the upper hand when it comes to evolution, maybe by transferring advantageous qualities such as antibiotic resistance. Historically, this has been going on throughout the overall time of Earth’s existence, but we have never been able to study or observe its affects on the planet. No one knows what this means or what may happen because of this. Will oceanic microbial species be dramatically changed by the incorporation of new (although ancient) bacterial genes? Will this genes cause new pathogenic disease? Will they be helpful as a source of green energy? No one knows the answers to these questions, however only time will tell if these theories may be true.
Another, quite interesting hypothesis this study may prove wrong, is the theory that bacteria arrived here on Earth from space. Because this study showed that excessive radiation caused the DNA in the bacteria to broken beyond repair, this theory of life on Earth may be up for debate. It may have proven that millions of years of travel through highly radioactive space on an ice-covered comet to land on Earth and be able grow and divide, may not be scientifically possible. Well, I guess we are going to have to look elsewhere for the answer to the question, where did life come from???
These scientific discoveries are what make the world so interesting. Although they may shut doors to theories we’ve thought to answer, they open so many more questions to the future of our planet and everyone who lives here.
National Geographic News