Living Under a Rock
In the spring of 2010, a team of teachers and scientists from around the world met in the arid Namib Desert in Africa to study simple life forms that may exist on other planets. Just where was this team of teachers and scientists looking for life? Under a rock.
The meeting in the desert was an expedition by Spaceward Bound, an educational program developed at NASA's Ames Research Center. The mission of Spaceward Bound is to train the next generation of space explorers by having students and teachers participate in the exploration of scientifically interesting but remote and extreme environments on Earth as analogs for human exploration of the moon and Mars.
The team of scientists and teachers from the U.S., Australia, South Africa, Hong Kong, the U.K. and Namibia met April 18-25, 2010, in the Namib Desert to investigate the role of fog in supporting microbial ecosystems in extreme deserts. The team was looking specifically for hypoliths -- translucent quartz stones, found in arid deserts, with colonies of one-celled photosynthetic organisms on the underside. The stones hold moisture and, if translucent, allow some light to penetrate.
Much can be learned about life on other planets by studying life in places like the Namib, where the conditions are similar. On a planet such as Mars, life may survive on sources of water other than rain, such as melting ice, fog and dew.
Spaceward Bound participants wrote in a post-trip report that the Namib Desert is possibly the best location in the world to study the relative effects of fog versus rain on supporting desert life. The Namib Desert, on the western coast of Africa, is similar to the arid core of the Atacama Desert in South America, with very little rain but with a marine fog coming in from the cold ocean. In the Atacama, high coastal mountains block the fog within a few kilometers from the coast. In the Namib, the land slopes gradually from the coast up to 1,800 meters (5,900 ft.) elevation near the capital, Windhoek, 300 kilometers (approx. 186 mi.) inland. The fog rolls up this slope, diminishing gradually with distance and elevation. As a result of the different geographies between the two deserts, fog is absent from the interior of the Atacama but is present in the interior of the Namib.
The scientific goal of the expedition was to compare the potential for life in each desert. In the Atacama, researchers found that the colonization of bacteria on stones essentially dropped off to zero in the arid core. They expected that in the Namib the stones would be colonized near the coast as a result of the fog and far inland as a result of the rain, but that there would be a zone of no colonization in between. To the team’s surprise, the colonization remained high across the desert.
In addition to finding naturally occurring hypoliths, U.S. science teacher Michael Wing brought with him to the field artificial quartz stones, which he placed on the desert floor for future study. Wing's ninth- and 10th-grade integrated science students at Sir Francis Drake High School in San Anselmo, Calif., prepared the stones. The placement of the artificial hypoliths was part of the Worldwide Artificial Hypoliths Project that Wing started after learning about hypolithic cyanobacteria at Spaceward Bound Mojave 2009. "This research idea was a direct result of that program and wouldn't be happening without it," he said.
Wing and his students will monitor the stones over the next few years to see if bacteria colonize. Wing also has placed artificial hypoliths in the White Mountains in California and Devon Island in the Canadian Arctic. He plans to place arrays of artificial hypoliths in the Mojave Desert in California in 2011.
Other research carried out during the expedition include investigating salt deposits associated with groundwater flows, moisture gradients in the subsurface, and clays in the sand sea to the south of the Gobebeb Desert Research Station where the team was staying.
Wing, who has taught at Sir Francis Drake High School since 1998, said his students' participation in the expedition and the hypoliths project has helped make science "real" to them. "All 120-plus of my students get to learn about my collaboration with NASA, see pictures and journal entries from my trips, and to participate directly a little bit -- they each prepare glass and marble 'stones' that they know will be deployed in the field in different places around the world. It helps make science real for them," he said. "But a few of my students get to go with me! Our school has made six expeditions so far to California's 14,000-foot White Mountain Peak, where natural hypoliths grow in abundance and where we have placed some artificial ones. Two dozen students have been on these expeditions, with more planned for 2011."
Spaceward Bound supports NASA's goal to attract and retain students in STEM disciplines through a progression of educational opportunities for undergraduate and graduate students in STEM and education, pre-service and in-service STEM K-12 teachers as well as STEM education faculty. Through field expeditions and Mars simulations, Spaceward Bound inspires, engages and educates members of the STEM education pipeline. The program prepares individuals for employment in disciplines needed to achieve NASA's mission and strategic goals.
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Heather R. Smith/NASA Educational Technology Services