The Irish time lords unlocking the secrets of our past
Scientists are opening time capsules left by nature that may offer leads on evolution or extraterrestrial life
Scientists have become time travellers by finding new ways to recreate conditions from the past, sometimes using techniques that sound more like science fiction than science fact.
The really important part of the Jurassic Park story was not that dinosaur DNA was mixed with frog genes to make an inter-aeon, inter-species cocktail to populate a T-Rex theme park. It was that millions of years previously, mosquitoes had sucked on the blood of their dinosaur contemporaries before getting trapped in fossilised tree resin.
Thus was made the window to the past for Crichton and Spielberg to imagine the Frankensteinian folly of cloning dinosaur DNA taken from the contents of the preserved mosquito bellies.
In the real world, Jurassic Park raked in more than $900 million at the box office, such was the interest in the time-defying fantasy. And so it has always been: humans are interested in what has been before; and from where, what and indeed whom they have come.
The fantasy bioengineering of Crichton’s fictional enterprise could never happen, but nature has contrived to safely store away evidence that may yet open up new leads on evolution and even extra- terrestrial life.
The Irish time lords
Time to meet the time lords of Irish science. They are sifting through depths of mud and peering into the world’s oldest rocks to unlock Earth’s secret history.
“I have a rock in my office that’s over four billion years old,” says Martin Feely, an expert in the origin and composition of rocks. “It’s a very famous piece of Earth’s crust from near Yellowknife in Canada.” He got the piece as a special favour from a colleague. “It’s the oldest known to man.”
Along with fellow geologist Alessandra Constanzo at NUI Galway’s Ryan Institute for environmental, marine and energy research, Feely is studying “epavorites”, such as halite and gypsum, to learn about the past.
“Evaporites are formed in hot and salty environments,” Dr Constanzo explains. “We have many that were formed over 250 million years ago in places such as Searles Lake near Death Valley in California. “Brine-rich environments got landlocked and cut off. As water evaporated, the brine was crystallised, forming the evaporites.”
The geologists are not only interested in the evaporites, however, but also in what may lie inside.
Prof Feely explains that, as the evaporites formed, so too did “imperfections at the atomic scale”. These imperfections trapped “mother fluid” from which the crystals grew. “The mother fluid contained, ergo, any microbes from the brine.”
The “fluid inclusions”, which Prof Feely calls “mini brine pools” inside the evaporites, might be “teeming with life”. And thus opens another window to past life.
Prof Feely and Dr Constanzo have joined with microbiologist Cindy Smith to take a geo-microbiological journey through time to investigate bacteria and algae trapped in fluid inclusions.
“These were extremophiles. They were thriving in hot, salty lakes – inhospitable places where no other organisms could make it,” says Dr Smith. Learning about them, trapped in their miniature time machines, “would be significant in understanding life millions of years ago”.
The researchers have found organic material and dead microbes in 250-million-year-old evaporites. In evaporites formed just over four years ago, they found living bacteria.
“We’re not sure whether they fall asleep or just tick over very slowly,” says Dr Smith. “But even a four-year-old bacterium, that’s very old – maybe the equivalent of a human living to be several million years old.”
Fraser Mitchell of TCD’s botany department is at the controls for an inter-millennial effort to reconstruct woodland dynamics based on identifying and counting fossil pollen preserved in peat and lake sediments.
“Trees grow over hundreds of years, and we can’t sit around watching,” he says. “So, we analyse fossil pollen to fast- forward the tape.”
Prof Mitchell is helping to manage today’s national parks. “What should we be aiming for?” he asks, saying that, though our ancestors “chopped down lots of oak” 200 years ago, “there were actually lots of pine woodlands 2,000 years ago”.
Forests of Aran and the Burren
One more time-travel stop and two more palaeoecologists. Michael O’Connell and Karen Molloy join to continue the journey into the past.
Would you believe the Aran Islands were wooded – with oak, elm, pine and hazel – for most of the past 11,600 years? Or that the Burren hills once supported open pinewoods under which today’s arctic and alpine plants flourished?
“By focusing on cereal pollen especially, human environmental impact is now reconstructed in detail unthinkable a generation ago,” says Prof O’Connell. Research by Prof O’Connell and Dr Molloy at NUI Galway enabled the reconstruction of the environmental impact of farming in archaeologically rich areas such as Céide Fields in north Co Mayo. It has, says Prof O’Connell, given important information on how “farming intensity waxed and waned over the course of centuries”.
Can this be taken even further? There’s “no doubt that water existed on Mars”, he says, “but it’s evaporated. If we’re to search for previous life on Mars, why not go there and look at fluid inclusions?”
Dr Gavin Collins is based at NUI Galway and is on placement at The Irish Times as a British Science Association Media Fellow, in collaboration with Science Foundation Ireland
A video to accompany this article can be found by searching for “trapped bacteria in evaporite” on youtube.com
Extreme life: Survival in space
The hunt for extreme life is taking scientists deep below ground and sending microbes piggy-backing rockets into space.
More than a kilometre below the surface, at the Boulby potash mine in northern England, researchers have set up a laboratory. “We are investigating how life survives in the deep subsurface,” says Charles Cockell, director of the UK Centre for Astrobiology, who is leading the effort. “These are extreme conditions. It’s very salty, dark and warm, and there’s no sunlight. They’re good conditions to understand whether life might be able to originate and grow in some of the extraterrestrial environments,” he says.
Prof Cockell has previously put bacteria into space to see how they would cope. “They were launched on a space shuttle and bolted onto the outside of the space station.”
Several of the bacteria survived the experience and are being analysed. “Our goal was to isolate microbes with capabilities that could be useful in space exploration and human settlement.”
Understanding how the survivors got through this ordeal may reveal clues about how life can survive in the harshest conditions imaginable, not just in caves underground but on Mars, on distant moons orbiting Jupiter or further afield.