Hock, who studies at UCLA, focuses more on geophysics, specifically on the habitability of geothermal environments. Fike is at MIT. He uses DNA analysis to understand what microorganisms inhabit an environment.
Hock and Fike spoke to Astrobiology Magazine to us from a stopover point known as "the Refuge," located 4,200 meters (13,800 feet) above sea level, near the base of Licancabur. They and the other team members have spent the past week exploring the hydrothermal environment of the nearby lakes.
Astrobiology Magazine: Can you set the scene for those of us who arent fortunate enough to be there with you?
Andy Hock: Right now the sun has just set. On the horizon you have these gigantic and beautiful volcanoes and the sky is fading from a sort of pinkish purple to a light blue, and out in front of me is a sign that says, "Este es mi tierra, Bolivia. Bienvenidos. (This is my land, Bolivia. Welcome.)" And beyond that is Laguna Blanca and a couple of remaining hungry flamingos.
AM: How has the expedition been going so far?
Hock: So far the experience has been tremendous. Its been physically challenging. We summitted a volcano called Tres Cumbres as a training exercise yesterday. That was a real challenge.
So was our first climb up Licancabur. We went to the middle camp, about 600 or 700 meters (1970 to 2200 feet) short of the summit, to the place where were going to spend one night. And that experience was not only physical, like Tres Cumbres, but also a very spiritual and emotional one. Ive always thought of outdoors as being my chapel. And getting out on Licancabur for the first time a couple of days ago was really spectacular.
And of course its been absolutely intellectually stimulating. We just end up developing more and more questions as time goes on. I guess thats the way science works you keep having more and more questions and the answers come in time.
The thing thats been most interesting to me as a geophysicist is how this gigantic geothermal reservoir associated with all these volcanoes, this gigantic heat reservoir, how it plays into the biology of the area.
The higher lake that Im looking out on now [Laguna Blanca] is about a kilometer or two in length, maybe a half a kilometer in width and only about a meter deep at its deepest point. And its full of flamingos.
I guess it would be probably 5 or 6 miles (8 or 9 kilometers) around. Ive walked around nearly the whole thing; it takes the better part of an afternoon to walk around. But everywhere I walk around, theres thermal water input.
The lake is about 13 to 15 degrees Celsius (55 to 59 Fahrenheit) on the whole, and these little spring outlets are maybe 15 to 22 degrees C (59 to 72 F). So all around the lake theres these little springs, and right by those springs, theres a tremendous amount of biomass: algae, bacteria.
I came here with a big, big interest in the summit lake. But without even having been there yet, weve already discovered tremendous scientific potential with these lagunas.
AM: David, can you describe some of these microbial environments?
David Fike: At the hot springs where water comes up at about 37 Celsius, roughly body temperature (98.6 F), you have rich mats of bacteria and algae that are photosynthesizing and producing oxygen like crazy. And at other places we have cold springs, where water comes up at from 20 Celsius (68 F) to 15 Celsius (59 F), which is approximately the temperature of the lake, and you have much different communities of bacteria there, and almost no algae. Each spring seems to have its own different microbial community, based on visual inspection, which is incredibly fascinating. It would take years to try and actually understand it.
AM: Have you been able to identify any of the organisms?
Fike: Not yet. Weve been looking at some soil and water samples, but its too soon to get any real data out of them. Ill have to wait till I get back to MIT to do some lab work before I can really understand them. Its really interesting to be here and to see the immense diversity of environments, but its frustrating because I dont have the tools here with me to actually understand what those visual differences actually relate to in terms of microbial diversity.
Some of the members of Team B are coming back on Wednesday and hopefully theyll be able to present the first analysis of the data they collected with us on their last visits. [Team B is working in a laboratory in Antofagasta, a city on the Chilean coast.]
AM: What about Laguna Verde?
Fike: I havent really had a chance to get over to Laguna Verde. It has much more mineral content to it. And it seems to have almost a uniform lack of algae and rich bacterial communities except for one area on its northern side where theres a small spring that feeds into the laguna, thats characterized by a rich algal and microbial community.
Hoke: People say theres a high content of arsenic, copper sulfate, which is what I would guess would give it its aquamarine tint. But its clearly very mineralized.
The Inca legend goes that these lagunas were right along one of the prime Inca trade routes. And when you ask people around here why Laguna Verde is so mineralized, its because when the Incas were traveling along this trade route with their pack animals and their gold and their sliver, and their copper, when the pack animals died, when they couldnt make the trip, they would always bury the pack animals with their burden. And so, the story goes around here and for all we know, it may be true that Laguna Verde is so mineralized because theres a whole bunch of old Inca metals, valuable metals, at the bottom.
AM: Theres also another lake not too far away, Laguna Colorado.
Hoke: We visited there today. Its blood red with white borax mineral deposits, so its a stark contrast of red and white. Its an extraordinary sight. Tons and tons of flamingos. Our driver told us today that they did a census on flamingos at Laguna Colorado and there were over 32,000. Thats going to be a place were going to really want to go back to.
AM: Whats been the most surprising thing being there?
Fike: The fact that everywhere I turn theres something interesting. In terms of science, there are areas of the lake, springs I dont understand, theres paleo shorelines that dont make any sense, theres weird rock formations Im trying to analyze, but also Im here on the border of Chile and Bolivia and Im exposed to new cultures and its really a broadening experience.
Hoke: I think for me it would be the amount of thermal water that I see. Ive never been to a place like this before, where you walk around the lake and every 10 meters or less you see a little spring outlet and biomass around it.
I look around and I see what I think are old shorelines and what looks like a gigantic lake basin. And so the picture starts coming together of how this place used to have a much larger body of water and how theres evidence for hydrothermal alteration all over the place. So theres this picture that comes together of water, heat and life in this place that is otherwise the driest desert in the world and subject to huge UV flux and otherwise pretty harsh.
So working together with the other members of the science team and sitting down after dinner and talking over the days observations were pulling together this picture from all of our observations. Thats been the most surprising thing so far thats been really great, especially for me as a young scientist.
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