Carbonate structures in deep lake provide insights into early life
8:38 a.m., Aug. 25, 2011--A deep lake in rural British Columbia might seem an unusual place to seek information about life on other planets, but researchers in fields ranging from nutrition and robotics to astrobiology and geochemistry are using the site not only to gather valuable data about the origins of life but also to develop tools for exploring unknown environments of all types.
Jennifer Biddle, assistant professor of marine biosciences at the University of Delaware, is one of the researchers contributing to the work, known as the Pavilion Lake Research Project (PLRP). The PLRP is an international, multidisciplinary science and exploration effort to explain the origin of freshwater microbialites, which are carbonate structures that form in water with the help of microorganisms.
Viral dark matter
These structures may hold answers to some of the most profound questions we can ask, says Joe Russell, a graduate student working with Biddle. What did some of the earliest life on this planet look like? How did it survive and evolve?
“Fossil records show that for a couple billion years of our planet’s history, life existed similarly to how it does on the microbialites of Pavilion and Kelly lakes,” Russell says. “If these structures were such an important first step in Earth’s life history, might they also be something to look for when we eventually explore other planetary bodies in our solar system and beyond?”
Biddle and Russell are currently carrying out an experiment to see how microbes living on microbialites in the depths of Pavilion Lake react when they are relocated to a shallower site.
“We hope to better understand the bacterial communities that live on the surface of the microbialites and drive their formation,” Biddle says. “Because microbial communities can double every 20 minutes, we could possibly see changes in DNA in periods as short as a week or two.”
“We’re also interested in pigments,” she adds. “Photosynthetic cyanobacteria are suspected of contributing to the formation of microbialites in these lakes. They harvest light using pigments, and they may help us understand why microbialites in different locations look different from each other.”
While the PLRP is yielding valuable scientific data for researchers like Biddle and Russell, the backstory behind the project, which is funded by NASA and the Canadian Space Agency, is interesting in itself.
“We’re taking an analog mission approach to the science and explorationcomplete with a mobile mission command center,” Biddle says. “With the space shuttle no longer launching, NASA is supporting work like the Pavilion Lake project for its potential to generate new knowledge about how to explore challenging environments.”
One-man submarines and autonomous underwater vehicles are used to explore and map remote sites like Pavilion Lake and Kelly Lake, which is located about 12 miles northwest of Pavilion.
“One disadvantage of a single manned sub is that only one person is seeing and observing things in real time,” Biddle points out. “Even if they take a video, the rest of us might wait hours to see it. That means decisions are slowed, and science might be impeded. So this year the team designed a way to have a sub tethered to a cable, sending video feeds to the surface, with the communications team shooting video back to the mobile mission command center.”
Another layer of mission realism was added when the team started doing delayed communications. “The Earth-to-Mars delay is about 30 seconds,” Biddle says, “and we wanted to simulate that. So even though our sub pilot was only a few kilometers away, we gave ourselves a delay to see how things would go.”
For Russell, few experiences can top traveling to Pavilion and plunging into the lake’s chilly waters to retrieve the plastic boxes holding his samples.
“This is the only environment where microbialites are found at such a variety of depths,” he says. “Our hope is that these varying growth environments, characterized by differential access to light, will highlight the features of microbialites that made them so successful on early Earth and could possibly aid their formation on other planetary bodies.”
About the research team
Jennifer Biddle is an assistant professor of marine biosciences in the College of Earth, Ocean, and Environment. Joe Russell is a master’s candidate in her research group. Their work at Pavilion Lake is supported by NASA’s Delaware Space Grant Consortium.
Article by Diane Kukich