You wouldn’t think that Antarctica, of all places, would have any relevance to deep space. You probably wouldn’t think that Antarctica would have something interesting to tell us about bacteria (not to mention that you probably don’t think bacteria are interesting anyway). You also wouldn’t think that Antarctica would have anything to do with life on other planets. And finally, you wouldn’t think that it might have something to reveal about good and bad science.
Surprise! One of the most astounding discoveries in 1984 was that of the famous ALH 84001 meteorite—in Allan Hills, Antarctica. It is believed that this rock was blasted off Mars by a meteor strike and, remarkably, found its way to earth. Furthermore, in 1996 there were reports saying that bacterial fossils had been discovered on ALH 84001. As with all good science, there ensued much debate. In this case the question was whether or not the “fossils” were produced by bacteria or by geologic processes having nothing to do with biology at all. The scientific jury is still out on this question, but I suspect most scientists believe they are not of bacterial origin and that, in fact, they are not fossils at all. They look pretty convincing under a microscope, but they are probably of geologic origin.
And then there is the fact that the ice cap on Antarctica is itself being used as a huge lens to look for neutrinos, which themselves tell us something about the solar system, but that is another story. Suffice it to say that this project, called, appropriately, “Ice Cube”, is a very large international effort taking advantage of the polar ice cap and the neutrino’s amazing ability to pass through the earth without hitting anything. But the rare one that does hit the ice cap gives off a little “flash” that can be detected. The pattern and timing of these flashes tells scientists about the origins of neutrinos in the universe, and can thus create a unique map of the heavens.
But Antarctica has something else of interest: an ice cap that is more than 30 million years old. Which means that at the bottom of the ice lies soil/sediment that may have remained uncontaminated for that whole time. So by looking at that soil/sediment, we can get a glimpse of the biology that existed there long ago. Furthermore, there are an estimated 400 lakes under the ice, with connecting “rivers.” And the water does not move very fast. Lake Vostok, which is the size of Lake Ontario, has an estimated turnover time of 13,000 years.
So, for scientists interested in discovering new bacteria and determining how bacteria live and evolve over time in this unique environment, this is a pretty attractive laboratory. Compare bacteria at the top with those at the bottom, and, well, who knows what you’d find. Certainly new species of bacteria. Why? Because there are strange environments down there unlike anywhere else on earth. For one thing, they are under extreme pressure due to the thickness of the ice cap—up to two miles in places. It is cold all the time, with a temperature range of -8F to 28F (more on this later). It is dark, so any life down there is not getting its energy from the sun (more on this, too). And it is, of course, wet.
In fact, scientists think that these conditions may be similar to those found under ice on other planets or moons. For example, the sixth moon of Jupiter, Europa, has ice on its surface, and there is believed to be water under the ice. So it may have features not unlike the underside of Antarctica’s ice cap. And therefore it MAY be a place where life has evolved—since it has some of the conditions for life, that is, liquid water. It also may have oxygen in its atmosphere. One of Saturn’s moons, Enceladus, appears to have water under its ice too, but scientists believe that, unlike Europa, the water on Enceladus is likely to be at or near the surface.
And so if life can be found in soil under Antarctica’s ice that has not seen the light of day for 30 million years, just possibly life could have evolved under similar conditions elsewhere in the Universe.
But even if Antarctica’s ice tells us nothing about biology in space, it is certainly cool science. Think about it—how would bacteria survive without access to the sun? With no plankton, no dead animals to feed on?
Well, first, to be exact, there are two “types” of bacteria—bacteria is one type, and the other is not strictly a bacteria at all. It is another ancient single-celled microorganism called “archaea”, which was lumped in with bacteria until the 1970s. At about that same time, researchers began to realize that these archaea, along with some bacteria, show tremendous flexibility in their ability to thrive in a wide range of environments. They can survive at temperatures as high as 252F (water boils at 212F). They can live at salt concentrations of 25% (sea water is only 3.1-3.8%). At least one species can live in solutions with a pH of 0.00—such as sulfuric acid. Rather than getting their energy from the sun, like you and I do, they can get their energy from such unexpected sources as hydrogen, iron, or ammonia. They can live off radioactive rocks. They can utilize oil or methane as food. They can live in black smokers at the bottom of the ocean, or they can live in the Earth’s crust—in 2010 scientists found bacteria beneath the basalt layer at a depth of one mile.
So it is tantalizing indeed to speculate that new species of archaea and/or bacteria might be discovered under an ice cap. You can also surmise that it would be a good idea to conduct the search in a STERILE manner so that when comparing bacteria at the top and the bottom you can say with some confidence that neither of them was planted there by you. It would also be nice if there was no contamination of the underlying ice and water with bacteria from the surface.
Currently there are three ongoing research projects in Antarctica whose purpose is to drill through the ice cap and continue down through long-covered lakes into the underlying sediment. The most well known, and longest running, of these projects was mounted by a team of Russian scientists to drill into Lake Vostok, a huge body of water the size of Lake Ontario, with water maybe 14 million years old. This attempt started 20 years ago, and the lake was finally reached in February of 2012 at a depth of 2.2 miles. Unfortunately, this may be an example of over-reaching scientific enthusiasm—although everyone agrees that the best way to drill in a sterile environment is by using sterile hot water, the Russians used a drill bit, Freon, and kerosene. They said that their power sources were not adequate to use sterile hot water. They also asserted that the pressure from the overlying ice would cause the kerosene and Freon to be pushed back up the drilling core, thus sealing it and preventing contamination of Lake Vostok. In October 2012, the Russian team reported preliminarily that the first 40 liters of water from the surface of the lake did have bacteria in it—bacteria similar to the bacteria in the kerosene. Well, actually they couldn’t identify one of the types that they found, but they think it may also be a contaminate from the kerosene. So no NEW bacteria, apparently. The science seems a little iffy to me. What do they mean they could not identify it?? And if they can’t, well, what does that mean? Ugh. Well, I hope kerosene-loving bacteria (or archaea) will not thrive in Lake Vostok.. But this year the Russians plan to descend down through the lake, hopefully taking water samples at all the layers, and start drilling into the sediment. 2013 will be exciting!
It would be fun for a 6th grade class to discuss reasons why it is a shame this couldn’t be done without contaminating the lake, how they would do the drilling differently, and how to interpret different hypothetical scenarios. Such as what would it mean if they find a bacteria that that they can’t identify? Or if all the bacteria they find look like those at the surface, what would that mean?! Then as a class project they could write a letter asking the Russians to leave a sign at their drill site advising scientists 10,000 years in the future that they were there first (hooray)—oh, and if the bacteria in Lake Vostok look like those on the surface, well, sorry, maybe it’s because they were in a hurry and contaminated the whole thing.
But, to be fair, we would also have to wonder whether we have contaminated Mars with our Rovers. But wait—NASA sterilized the Rover and all its parts. What a good idea!
There is also a team of British scientists in Antarctica, and they are doing it right. After 16 years of planning, the British team started drilling two miles down to Lake Ellsworth in mid-December 2012— with sterile hot water, inside sterile tents. The hot water stream is irradiated with UV light to kill bacteria (and hopefully archaea). All the drilling parts have been sterilized to the standards of a surgery room. They estimate that it would take them 100 hours to reach the lake, and a few more to take 2.4 liters of water samples and drill into the lakebed sediment. Note that the Russians took 40 liters as their initial sample. (I wonder which team is using the most sensitive and modern equipment?) So think of it—the British scientists are probably analyzing the results right now back in England. I can hardly sleep at night wondering what they have found! And I will have a great deal of faith in whatever they report. (Ah, an article dated 1/28/13 indicates that the British ran into technical problems and stopped drilling!! AHHH! We will have to wait to see how far they got and what they have found.)
And, of course, the Americans are at it too. Employing techniques similar to those used by the British, they are drilling into Lake Whillans, which is only 2,600 feet (about half a mile) below the surface. They are starting this month (January 2013).
Another American team has drilled down into Lake Vida, and they published their results in 2012. Drilling through an ice cover 2,800 years old and only 16 meters thick, they discovered a highly salty slush—approaching 20% salinity (sea water being about 3.5%). And it is cold—minus 8.5F. Remember that water normally freezes at 32F, but salt lowers the freezing point. Very little light penetrated the ice cover, and there was no oxygen, but their water samples were teeming with bacteria! And it seems these bacteria were deriving their energy from a potentially vast array of molecules—including hydrogen, methane, ammonia, and iron.
All of this is very exciting. Unfortunately we won’t have a drilling rig to do the same thing on Enceladus in my lifetime, I’m sure, but whenever it happens, I hope they won’t be cutting corners to save money.
If you don’t have the budget to do science right, it is really best not to do it at all. Ambiguous results benefit no one.
Surprise! One of the most astounding discoveries in 1984 was that of the famous ALH 84001 meteorite—in Allan Hills, Antarctica. It is believed that this rock was blasted off Mars by a meteor strike and, remarkably, found its way to earth. Furthermore, in 1996 there were reports saying that bacterial fossils had been discovered on ALH 84001. As with all good science, there ensued much debate. In this case the question was whether or not the “fossils” were produced by bacteria or by geologic processes having nothing to do with biology at all. The scientific jury is still out on this question, but I suspect most scientists believe they are not of bacterial origin and that, in fact, they are not fossils at all. They look pretty convincing under a microscope, but they are probably of geologic origin.
And then there is the fact that the ice cap on Antarctica is itself being used as a huge lens to look for neutrinos, which themselves tell us something about the solar system, but that is another story. Suffice it to say that this project, called, appropriately, “Ice Cube”, is a very large international effort taking advantage of the polar ice cap and the neutrino’s amazing ability to pass through the earth without hitting anything. But the rare one that does hit the ice cap gives off a little “flash” that can be detected. The pattern and timing of these flashes tells scientists about the origins of neutrinos in the universe, and can thus create a unique map of the heavens.
But Antarctica has something else of interest: an ice cap that is more than 30 million years old. Which means that at the bottom of the ice lies soil/sediment that may have remained uncontaminated for that whole time. So by looking at that soil/sediment, we can get a glimpse of the biology that existed there long ago. Furthermore, there are an estimated 400 lakes under the ice, with connecting “rivers.” And the water does not move very fast. Lake Vostok, which is the size of Lake Ontario, has an estimated turnover time of 13,000 years.
So, for scientists interested in discovering new bacteria and determining how bacteria live and evolve over time in this unique environment, this is a pretty attractive laboratory. Compare bacteria at the top with those at the bottom, and, well, who knows what you’d find. Certainly new species of bacteria. Why? Because there are strange environments down there unlike anywhere else on earth. For one thing, they are under extreme pressure due to the thickness of the ice cap—up to two miles in places. It is cold all the time, with a temperature range of -8F to 28F (more on this later). It is dark, so any life down there is not getting its energy from the sun (more on this, too). And it is, of course, wet.
In fact, scientists think that these conditions may be similar to those found under ice on other planets or moons. For example, the sixth moon of Jupiter, Europa, has ice on its surface, and there is believed to be water under the ice. So it may have features not unlike the underside of Antarctica’s ice cap. And therefore it MAY be a place where life has evolved—since it has some of the conditions for life, that is, liquid water. It also may have oxygen in its atmosphere. One of Saturn’s moons, Enceladus, appears to have water under its ice too, but scientists believe that, unlike Europa, the water on Enceladus is likely to be at or near the surface.
And so if life can be found in soil under Antarctica’s ice that has not seen the light of day for 30 million years, just possibly life could have evolved under similar conditions elsewhere in the Universe.
But even if Antarctica’s ice tells us nothing about biology in space, it is certainly cool science. Think about it—how would bacteria survive without access to the sun? With no plankton, no dead animals to feed on?
Well, first, to be exact, there are two “types” of bacteria—bacteria is one type, and the other is not strictly a bacteria at all. It is another ancient single-celled microorganism called “archaea”, which was lumped in with bacteria until the 1970s. At about that same time, researchers began to realize that these archaea, along with some bacteria, show tremendous flexibility in their ability to thrive in a wide range of environments. They can survive at temperatures as high as 252F (water boils at 212F). They can live at salt concentrations of 25% (sea water is only 3.1-3.8%). At least one species can live in solutions with a pH of 0.00—such as sulfuric acid. Rather than getting their energy from the sun, like you and I do, they can get their energy from such unexpected sources as hydrogen, iron, or ammonia. They can live off radioactive rocks. They can utilize oil or methane as food. They can live in black smokers at the bottom of the ocean, or they can live in the Earth’s crust—in 2010 scientists found bacteria beneath the basalt layer at a depth of one mile.
So it is tantalizing indeed to speculate that new species of archaea and/or bacteria might be discovered under an ice cap. You can also surmise that it would be a good idea to conduct the search in a STERILE manner so that when comparing bacteria at the top and the bottom you can say with some confidence that neither of them was planted there by you. It would also be nice if there was no contamination of the underlying ice and water with bacteria from the surface.
Currently there are three ongoing research projects in Antarctica whose purpose is to drill through the ice cap and continue down through long-covered lakes into the underlying sediment. The most well known, and longest running, of these projects was mounted by a team of Russian scientists to drill into Lake Vostok, a huge body of water the size of Lake Ontario, with water maybe 14 million years old. This attempt started 20 years ago, and the lake was finally reached in February of 2012 at a depth of 2.2 miles. Unfortunately, this may be an example of over-reaching scientific enthusiasm—although everyone agrees that the best way to drill in a sterile environment is by using sterile hot water, the Russians used a drill bit, Freon, and kerosene. They said that their power sources were not adequate to use sterile hot water. They also asserted that the pressure from the overlying ice would cause the kerosene and Freon to be pushed back up the drilling core, thus sealing it and preventing contamination of Lake Vostok. In October 2012, the Russian team reported preliminarily that the first 40 liters of water from the surface of the lake did have bacteria in it—bacteria similar to the bacteria in the kerosene. Well, actually they couldn’t identify one of the types that they found, but they think it may also be a contaminate from the kerosene. So no NEW bacteria, apparently. The science seems a little iffy to me. What do they mean they could not identify it?? And if they can’t, well, what does that mean? Ugh. Well, I hope kerosene-loving bacteria (or archaea) will not thrive in Lake Vostok.. But this year the Russians plan to descend down through the lake, hopefully taking water samples at all the layers, and start drilling into the sediment. 2013 will be exciting!
It would be fun for a 6th grade class to discuss reasons why it is a shame this couldn’t be done without contaminating the lake, how they would do the drilling differently, and how to interpret different hypothetical scenarios. Such as what would it mean if they find a bacteria that that they can’t identify? Or if all the bacteria they find look like those at the surface, what would that mean?! Then as a class project they could write a letter asking the Russians to leave a sign at their drill site advising scientists 10,000 years in the future that they were there first (hooray)—oh, and if the bacteria in Lake Vostok look like those on the surface, well, sorry, maybe it’s because they were in a hurry and contaminated the whole thing.
But, to be fair, we would also have to wonder whether we have contaminated Mars with our Rovers. But wait—NASA sterilized the Rover and all its parts. What a good idea!
There is also a team of British scientists in Antarctica, and they are doing it right. After 16 years of planning, the British team started drilling two miles down to Lake Ellsworth in mid-December 2012— with sterile hot water, inside sterile tents. The hot water stream is irradiated with UV light to kill bacteria (and hopefully archaea). All the drilling parts have been sterilized to the standards of a surgery room. They estimate that it would take them 100 hours to reach the lake, and a few more to take 2.4 liters of water samples and drill into the lakebed sediment. Note that the Russians took 40 liters as their initial sample. (I wonder which team is using the most sensitive and modern equipment?) So think of it—the British scientists are probably analyzing the results right now back in England. I can hardly sleep at night wondering what they have found! And I will have a great deal of faith in whatever they report. (Ah, an article dated 1/28/13 indicates that the British ran into technical problems and stopped drilling!! AHHH! We will have to wait to see how far they got and what they have found.)
And, of course, the Americans are at it too. Employing techniques similar to those used by the British, they are drilling into Lake Whillans, which is only 2,600 feet (about half a mile) below the surface. They are starting this month (January 2013).
Another American team has drilled down into Lake Vida, and they published their results in 2012. Drilling through an ice cover 2,800 years old and only 16 meters thick, they discovered a highly salty slush—approaching 20% salinity (sea water being about 3.5%). And it is cold—minus 8.5F. Remember that water normally freezes at 32F, but salt lowers the freezing point. Very little light penetrated the ice cover, and there was no oxygen, but their water samples were teeming with bacteria! And it seems these bacteria were deriving their energy from a potentially vast array of molecules—including hydrogen, methane, ammonia, and iron.
All of this is very exciting. Unfortunately we won’t have a drilling rig to do the same thing on Enceladus in my lifetime, I’m sure, but whenever it happens, I hope they won’t be cutting corners to save money.
If you don’t have the budget to do science right, it is really best not to do it at all. Ambiguous results benefit no one.
No comments:
Post a Comment