Tuesday 20th November 2007 by C. Freeman
The lecture theatre at Brooke Weston was filled with prehistoric gases as students handled ancient ice samples extracted from Antarctica. Bubbles trapped in the ice popped and fizzed, releasing tiny amounts of gas from 300,000 years ago.
Scientist Mr Neil Wilson, also brought along 150,000-year-old fossils to accompany his talk on the work of the British Antarctic Survey.
He lectured on the continent's weather patterns, species and the unique problems facing scientists working in its extreme conditions. Antarctic researchers have to ensure they are equipped for every eventuality. As well as danger from the cold (with frostbite possible from the relatively mild temperature of minus 29 degrees) scientists are also at risk from sunburn as the UV levels above the Antarctic are higher than those at the equator in summer. Exposed flesh can burn badly, but the extreme cold means that sufferers don't necessarily notice until too late. Add to that the 24 hours of Antarctic darkness that the continent is plunged into for 100 days a year, and you get some idea of just how isolated the continent is. (There's just two collections annually from the local post office in Port Lockroy!)
Research workers are literally thrown in at the deep end, with practical training on how to get out of crevasses. These can open up at any moment, dropping people and equipment into massive chasms of ice hidden under the surface. Workers always travel around in roped pairs so that if one does slip into a crevasse then the other should be able to assist. They are also equipped with knives after a lone worker got his hand entangled in the fan-belt of his skidoo engine. His radio was in the skidoo so he couldn't call for help. Mr Wilson said: 'The only thing he could do was to actually cut his fingers off. Because that knife saved his life everybody now carries a knife that you can open with one hand and it is tough enough to amputate fingers or limbs.'
Mr Wilson illustrated his talk with a slideshow and ammonite and lobster fossils dating from 150 million years ago as well as a petrified tropical tree stump. Handing round the ice samples bored from beneath the Antarctic wilderness, Mr Wilson explained: '300,000 years ago that was falling as snow. The air gets trapped in it and then more snow falls on top and it all freezes. Over a period of time it becomes compressed which is why you can hear those bubbles popping, because they are all under pressure. In fact, if you throw that into a cup of warm water you would actually see it hiss as the ice melts more quickly and those air bubbles come off. Trapped in that air are isotopes of the atmosphere of that time and you can analyse them and tell what the climate was like when that snow fell. It gives you a picture of climate change over a period of time.'
Scientists can also track back human and volcanic history in the extracted ice cores which have trapped particles of lead and radiation in them.
Mr Wilson said: 'If you go back there's no radiation in the ice because all that snow fell before atomic testing and, as you go through you get dust from every volcanic eruption. When Krakatoa erupted the amount of dust that was thrown up into the atmosphere affected the world's weather for two years. Although it happened in Indonesia you were getting spectacular sunsets and vile winters in London as a result of that volcanic eruption. Every volcano has a characteristic dust pattern so you can analyse that and but you can start to see this picture emerging of what is happening in our atmosphere.'