Diving for Life under Antarctic Ice
|McMurdo Dry Valleys, Antarctica. Credit: BAS|
Dale Andersen is a biologist at McGill University, the SETI Institute and NASA Ames. His research focuses on Mars analogs, locations on Earth that resemble Mars in one or more ways. By studying these analog sites, Andersen hopes to learn about how life might have begun – or might still survive – on Mars. Much of his time is spent in very cold places, Antarctica and the Arctic. His specialty is ice diving. In a recent talk given at a NASA symposium on risk management in Monterey, California, Andersen described some of his work in the polar regions. His remarks are excerpted below.
We started our research in Antarctica back in the late 70s working at some of the lakes that are in the McMurdo Dry Valleys. This is one of the largest ice-free regions that exist there. There is a series of lakes with very, very thick ice cover, and nobody had ever probed these lakes before, and looked at them in depth, other than just taking some drills and popping small holes in them, and sort of taking a soda straw approach. We wanted to look at them in little different fashion.
There is not a lot of ice in the valley itself. The evaporation highly exceeds the precipitation, so it’s quite dry. But there are some lakes there. At one of these lakes, Lake Hoare, we spent quite a bit of time studying the lake ecosystem. These lakes are permanently covered in ice, and the ice thickness ranges from about 3 meters (10 feet) up to 6 meters (20 feet). In earlier years about the only way people studied the lakes was to go out and drill a small hole through it, and then take water samples and take some other measurements. Nobody ever really asked the question, what’s going on at the bottom? Most people thought the light levels were so low that there wouldn’t be anything on the bottom.
|Cold microbes underneath the ice.
A few years later we decided to open these lakes up with a bigger hole so that we could go down and look. For some reason we weren’t smart enough, or maybe at that time underwater cameras were still a hassle to get ahold of, so it was just as easy to go put us in the water as it was to take a little camera and drop it down the hole.
So we developed a system that allowed us to melt holes through this ice. We take a copper coil and put a hot solution through it, and let it melt down the ice. And we can move in and out of that ice cover, as we’re melting it. We’re essentially creating a tunnel, a water tunnel. And then we suit up and we jump in. Originally we started out in wet suits with double hose regulators, which is kind of ancient history. But over the years we realized that wasn’t the best solution, because if it’s minus 30 C (minus 22 F) when you get out, you’ve got to deal with a really cold wet suit. It’s not too comfortable to take a wet suit off in those conditions. So we went to dry suits and whole face masks.
Why did we go to these places? That to me was the biggest payoff. Some of the program managers who were associated with the project told us, just before we were getting ready to go in for the first time, that we were just going to find a bunch of rocks, and that we’d wasted everybody’s time and money. But what we found was a really lush, luxuriant microbial ecosystem that had never been seen before. And as it turns out, these tunnels that we make through the ice are just like tunnels back through time, 600 million years to 3.5 billion years ago. This gives us a glimpse of early Earth, and perhaps of early Mars. If lakes existed on Mars, they would possibly have been ice covered, and possibly have microbial communities similar to what we see in the dry valley.
Now, we just don’t follow the microbial communities underwater. We also follow them wherever we can find them. That includes on top of the glaciers. We have to pick up ice climbing skills and some general mountaineering skills when we want to go up into the alpine areas. So it’s a real skill mix to work in these kinds of regions.
|Climbing in before diving in.
Now more recently I have shifted poles, and we are now working in the Canadian high Arctic. The setting there is not altogether that different. It is very, very glaciated. There are large Alpine glaciers along with large ice sheets. We’re studying a series of perennial springs in this region. These are the highest latitude perennial springs in the world, along with the set that’s over in Svalbaard at Bokfjord. This is a great Mars analog. If there were springs on Mars coming up through thick continuous permafrost, this is where we would go to see these.