Science Interviews


Sun, 22nd Jul 2007

Surviving Antarctica

David Thomas, University of Wales, Bangor.

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Frozen Oceans - By David ThomasChris - As someone who has been to both the poles for his research, you have survived and come back. Itís a horrible place thought, isnít it? How cold is it at the poles?

David - Well it must be said that we go mostly in the summer, so actually quite often we will be working on the ice in T-shirts because if the sun is at a high angle itís just like being in Switzerland and being warmed by the Sun. But at the South Pole, the coldest temperature has been Ė80 degrees centigrade, so about the temperature of liquid nitrogen really.

Helen - Thatís really quite cold!

Chris - Yes, itís pretty chilly! How does life survive there, or is it just a barren wilderness with nothing?

David - No, thereís plenty of bacteria that are living in the uppermost snow on the south pole, and most of these organisms they kind of go down into a diapause or a hibernation, they just go into resting stages until conditions get better. Myself, I study microscopic algae that get caught up into ice in frozen sea water, and when temperatures get really cold they just switch down their metabolism to a basal rate and then wait for the conditions to get better. Thatís a general principal, same for polar bears really, as well.

Chris - So if you look in the ice, itís not the sterile thing that we think it is, thereís quite a lot of life hidden in there.

David - Thereís a lot of viruses, a lot of bacteriaÖ itís teeming with life. Even very ancient ice that is hundreds of thousands of years old, has bacteria that have been brought back to life when this ice has been retrieved from these deep ice cores that people are taking in Greenland and the Antarctic.

Chris - Itís intriguing to me that we put into our deep freeze at home food to make sure that it wont go off. It suppresses the activity of life which degrades food, thatís at about Ė20 degrees. Youíre playing around in those temperatures and youíve got things that you say are thriving. So how do they survive and flourish in those temperatures?

David - So weíve actually got bacteria that are moving around at Ė20, this is the same temperature as your freezer in the sea ice. One of the things they do is the produce a lot of slime; they produce a lot of mucous. They protect their cells within [the slime] and sit in this gel-like body that buffers them against a lot of the temperature and also saline stresses that they may come into contact with.

Chris - Is it true that things like Unilever, big companies like them, have borrowed from biology and solved the problem of how to make smooth ice cream by nicking the chemistry that some of these microbes have invented for themselves?

David - Thereís a whole new industry of bio-prospecting in the poles, and people are looking for enzymes that work at particularly cold temperatures, substances that make, as you say, ice-cream smooth at cold temperatures. Thereís a whole group of industries that are out there that are looking to the poles for solving many of these kinds of problems.

Chris - One of the things you said was that on a hot day it can be like youíre on the ski slopes of Switzerland and you have to be careful not to get burned, because thereís lots of UV. So 2 questions come out of that: One; how do these organisms not actually get zapped by the UV and B; if thereís a massive ozone hole over Antarctica now, is that compromising these organisms?

David - A lot of the organisms that live down there are able to react very quickly to changing light conditions. Theyíre able to produce a whole string of pigments and also special amino acids that they are able to produce their own sunscreens, if you like. In turn, these microalgae and bacteria that produce these substances are eaten by things like the crustacea, the krill, as I gather was mentioned last week. They take on these sunscreen compounds via their diet, basically.

Chris - Ah, so one borrows from the other.

David - Exactly.

Chris - Thatís neat, so can we nick that and use it to make better suncreams for us? Especially if this ozone hole gets any bigger?

David - I donít think we need to. But one of the things is that when the ozone hole was first identified, a lot of biologists got a lot of research money out of this as everyone thought that this is going to be catastrophic to biology in polar regions. I think the last 10-15 years of research has shown that it probably isnít as catastrophic as first thought, the biology is really able to cope pretty remarkably, actually.

Chris - So thatís the hole in the ozone layer, but what about the other big problem which is said to be effecting Antarctica, which is global warming, and melting. Thereís conflicting stories, some people are saying some bits of Antarctica are getting warmer, some bits are getting colder, whatís the real story and how does it all fit together.

David - I think whatís interesting here is that we do have regions of the Antarctic, the Antarctic peninsula, which is probably the area of the globe that is heating up the most, or at the fastest rate. In general, itís thought that the Antarctic isnít really suffering as such from global climate change. Where things are really happening is up in the Arctic, where we know that in 2050 (so within our lifetimes hopefully) there will be no sea ice in the summer. There will be always sea ice in the winter, but there will be no sea ice in the summer in the 2050s.

Chris - Whatís melting it?

David - Just increase in temperature. Temperatures are increasing dramatically over the past 30 years.

Chris - Is that the sea temperature, so itís melting from beneath, or is that the air temperature, so itís melting from above?

David - Itís both, actually, so the thought of an ice-free Arctic, itís great for the shipping companies, who are going to be able to use the North West passages and the North East passages. But for things like the polar bears that are getting so much press at the moment, and also for the ecosystem. Thereís a whole ecosystem thatís based on having a frozen ocean for a whole year up in the Arctic. Of course, we donít know what the consequences will be.

Chris - Donít polar bears do something clever when they walk across ice, because they can in some way intuitively test where it will take them?

David - They can, they kind of splay their legs out and crawl, so theyíre spreading the load of their body, but it doesnít really matter if they fall through, to be honest, as polar bears are fantastic swimmers anyway.

Chris - Now, you said that Antarctica isnít really suffering that much, but what about the fact that the ice sheet Larsen B and then other ones which weíve seen previously, theyíve actually been of the order of thousands of square kilometres of ice Ė is that not significant?

David - Itís certainly significant, but these kinds of ice-shelf break-ups have been happening throughout geological time, so theyíre part of a natural process. An ice shelf comes to an end and breaks off. It is true though, Larsen B is on the Antarctic peninsula and itís very likely that thatís associated with the warming of the peninsula area.

Chris - Do you think then that itís too late from this global warming point of view? Are we going to see unequivocal losses that we canít remedy, in terms of the ecosystems and environments, or do you think that if we do start acting now we can turn things around?

David's book, Frozen Oceans, is available online through Amazon:

Frozen Oceans - By David Thomas

David - No, I donít think we can start turning things around, and cyclical changes like this have been well known in geological time. In the past there was tropical plants growing up in the Arctic region, so this is nothing new. What weíve done, I think in the last couple of hundred years, is weíve increased the rate of change of something that was happening quite naturally. My guess is we canít turn things around, weíre not going to stop this pack ice going in the Arctic. But it must be said that with many of these changes, weíve seen big cycles in climate change in the past.

Chris - I suppose itís good news, as my sort of final point, for fishermen, because up in the northern hemisphere, where theyíve been restricted by quotas and declining fish stocks, some of them have taken to catching icebergs instead. I did read one story where thereís quite a big market for the water from icebergs.

David - There has been lots of ideas throughout time of taking icebergs and dragging them to Arabian countries as a source of fresh water, and this is an idea that doesnít ever seem to go away.

Chris - There must be quite a lot of water locked up in an iceberg, there must be millions of tonnes.

David - Thereís massive amounts of water, especially when you add up the amount of water thatís in an ice shelf or an ice cap. Itís just staggering amounts.


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