Stormy Skies and Garden Worlds
And it snowed. Not down here in base camp. Here we got a half an hour or so of light rain. But up on Cerro Echaurren to the north and even more so on Meson Alto to the east, there are new dustings of white powder. That may not seem odd to those of you reading this in the northern hemisphere, where winter is approaching. But here below the Equator, we are only two weeks from the first day of summer.
Although some of us would prefer to sit on a rock overlooking the lake, listening to the wind and watching cloud formations roll through, the threat of thunderstorms has sent us scurrying to zip up the rain flies on our tents and has forced most of our activity indoors. It has also put a temporary halt to biological sampling on the lake.
But biologists are dedicated lot, and some members of the PLL team have plenty of samples, collected when the weather was better, that need to be filtered and prepared for laboratory analysis. This process involves sucking up water, liters and liters of water collected from Laguna Negra and Laguna Lo Encañado, into a syringe, some 50 milliliters at a time, and then forcing the water through a small circular filter laced with pores tiny enough to trap microbial cells.
Some of these filters are preserved in ethanol, for later DNA extraction. Other filters are kept on dry ice until they can be transported down to Santiago de Chile University, where they will be freeze-dried for the trip back to Madrid, Spain.
Madrid is where microbial ecologists Yolanda Blanco and Luis A. Rivas work, at the Centro de Astrobiología. They are part of a team that for the past several years has been developing a life-detection device, a device they hope will be sent one day to Mars, or perhaps to other worlds in our solar system, in search of evidence for extra-terrestrial life.
The device goes by the name SOLID (Signs Of LIfe Detector), which includes an antibody microarray in its sample analysis unit. This microarray crams hundreds of microscopic dots, each a distinct biological probe, onto a small glass slide. The dots, printed onto the slide, contain antibodies. Some of these antibodies react to specific types of organisms. Others react to common biological molecules, such as amino acids, the building blocks of proteins; or the lipids found in cell walls. Unlike past life-detection methods that look for biosignatures by heating a sample to high temperatures and sniffing at the released gases, the antibody-microarray approach is less destructive, more precise and capable of searching for hundreds of different biosignatures simultaneously.
Blanco, Rivas and their colleagues previously tested detectors at Rio Tinto, in Spain, and in Chile’s Atacama Desert, each time with a slightly different emphasis tuned to the environmental conditions of those field sites. One focus of the work at Laguna Negra will be looking for psychrophilic, or cold-loving, organisms.
The Garden World of the Northwest Shore
Posted on Friday, December 9, 2011
So far, our activities have focused on the waters along the southern shore of Laguna Negra, with occasional side trips to Laguna Lo Encañado to collect samples. But yesterday, for the first time, PLL team members Liam Pedersen and Chris Haberle struck out in the battery-powered Zodiac, Mariner 1, on a 40-minute, 4-kilometer journey to the northwest shore of the lake.
Laguna Negra is only 1.5 kilometers wide, but it is 6 kilometers long, the longer direction running north-south. The lake has two long “fingers” that stretch north, one to the northwest, the other to the northeast.
PLL Base Camp is situated at the center of the southern shore. The Echaurren glacier, however, sits high above the northwest finger. The team has been anxious to do research in this area, because it is where interaction between the glacier and the lake is likely to be greatest. That also makes it an ideal spot to consider as a summer home for the Planetary Lake Lander.
What a difference a few kilometers makes. Upon approaching the shoreline, the PLL advance team spotted underwater caves with denser vegetation than the scraggly assortment of plants along the southern shore. Then they saw the streams, lined with lush vegetation, and displays of wildflowers. And the massive waterfall, Victoria’s Cascade, named by the expedition that explored the area a century and a half ago.
There is a small area on the northwest shore where this turbid water can be seen diffusing into the lake, but because it’s colder than the lake water, it quickly sinks to the bottom, mixing very little with the otherwise transparent lake.
It is just this interaction between the glacier and the lake, however, and the difference between this area, which can support a distinct ecosystem, and other parts of the lake, that makes it scientifically appealing – and a potential long-term site for the Planetary Lake Lander.
Fortunately, communications tests conducted between the northwest-shore landing site and PLL Base Camp were successful, making the prospect of situating the lake lander there for the summer even more promising.