Site 1 for testing biological soil crusts in the Mojave Desert
I’m in the Mojave Desert with a group of astrobiologists from NASA Ames, JPL, and the California State University system, along with student teachers in the Spaceward Bound program.
Rakesh Mogul, Chris McKay, and Parag Vaishampayan
Today, March 19, 2012 we officially began the main activity of this field research: collecting samples of biological soil crusts. We hope our research is on the cusp of crusty research . . . or something like that. We have two questions: First, what are the components and abundances of crusts in various locations; and second, what causes these crusts to change density from site to site? We discussed how to approach these questions on Sunday night and decided on an experimental procedure. Dr. Rakesh Mogul first led us in an activity on assigning planetary protection protocols to various types of space missions as a way of looking at the variables and possibilities of contamination. Then we got down to business on the study itself. We decided to sample three locations along Kelbaker Road, which heads east from Baker across the Mojave National Preserve to Kelso Depot. We brought with us sampling tools and equipment, including a field handheld ATP analyzer and collection tubes.
Photographing Site 1 location A
We collected after breakfast on a cool morning. The wind had calmed down from the night before and it looked to be a beautiful day as we loaded the vans and headed out. We stopped first at a site about five miles east of Baker which had been scouted out earlier. This site had an intermediate or average amount of biological soil crusts (BSC). Chris McKay described the general goals at each site, and Rakesh worked through the procedures as we divided up tasks.
We had several things we needed to do: First, locate an origin point with an average amount of soil crust and lay down a frame and grid aligned to the compass and its GPS coordinates recorded. Then we set up a vertical tripod and took photos of the location. All of this was to allow for determining the density of the crust – how many of the grid squares were covered.
Second, Rakesh and some of the teachers collected samples to test for ATP using a handheld analyzer. This wound up being a slow procedure and took some
Sampling ATP at Site 1
Third, Dr. Parag Vaishampayan of JPL collected samples near the grid, both of crust and non-crust areas, that we would use to extract the DNA and perform polymerase chain reaction (PCR) procedures to increase the DNA for testing (this would be done back at the Desert Station lab). We also collected soil samples to analyze chemically. At each location, we also sampled four other locations, each randomly selected using GPS coordinates in an array around the original location.
Collecting soil samples at Site 1
With all this done and samples labeled and stored, we moved on down the road to the second site, this one with a dense growth of BSC. We ate lunch, then followed the same procedure to collect samples at five locations at the site. Since the crust was so dense, we had to be very careful not to step on any areas unless there was a wash or stream without crust.
Sample grid at Site 2
Dense, mature soil crust at Site 2
We then loaded up again and travelled back through Baker to our third site about two miles west of town across the road from Silver Lake. Here, the soil was very poor in soil crusts – we found a few small spots about the size of a quarter coin, all surrounding small puddles where organic matter and water had ponded. The BSC was much lighter in color and much sparser. We followed the same procedures, setting up grids, collecting samples, testing ATP, etc.
Site 3 near Baker, CA.
Collection Site 2
By then the afternoon had worn on and it was time to head back to the Zzyzx station. As soon as we got there our math wizards started setting up statistical searches and crunching the numbers. Tomorrow we’ll do the laboratory tests and prepare the samples by extracting DNA, sorting the soil, and testing the soil chemistry. We hope our results will be worthy of publication in their own right, as well as point to future ideas and techniques for studying life on other planets.
Chris McKay at Site 3
ATP sampling at Site 3
The Elements Unearthed 