Now, a research team led by biogeochemists from the University of Georgia has discovered at the site a previously unreported chemical mechanism for the production of nitrous oxide, an important greenhouse gas. Possibly even more important, the discovery could help space scientists understand the meaning of similar brine pools in a place whose ecosystem most closely resembles that of Don Juan Pond: Mars.
The research, published April 25 in the journal Nature Geoscience, adds an intriguing new variable to growing evidence that there has been—and may still be—liquid water on Mars, a usual prerequisite for the formation of life. In fact, the new findings could help space scientists develop sensors for detecting such brines on Mars—thus narrowing the search for places where life may exist.
"The pond's soils and brines and the surrounding rock types are similar to those found on Mars," said Samantha Joye, a faculty member in the department of marine sciences in the Franklin College of Arts and Sciences and lead author on the paper. "So it provides an ideal location to assess microbial activity in extreme environments. While we did not detect any 'bio-gases' such as hydrogen sulfide and methane, we did, surprisingly, measure high concentrations of nitrous oxide, which is normally an indicator of microbial activity. We needed to find out whether a non-organic process could account for this nitrous oxide production."
Other authors on the paper include Vladimir Samarkin, a research scientist, and Marshall Bowles, a graduate student, also of the department of marine sciences at UGA; Michael Madigan of Southern Illinois University; Karen Casciotti of the Woods Hole Oceanographic Institution; John Priscu of Montana State University; and Christopher McKay of the Ames Research Center of NASA.
The research was supported by grants from the National Science Foundation's Antarctic Organisms and Ecosystems Program and the McMurdo Microbial Observatory Program.Scientists have been fascinated with Don Juan Pond since its discovery in 1961. (While the site is lovely, there's nothing romantic about the name, which comes from the helicopter pilots who first found it, Don Roe and John Hickey.) From the time of its discovery, researchers realized they had found a place like nowhere else on Earth.
"What we found was a suite of brine-rock reactions that generates a variety of products, including nitrous oxide and hydrogen," said Joye. "In addition to Don Juan Pond, this novel mechanism may occur in other environments on Earth as well and could serve as both an important component of the Martian nitrogen cycle and a source of fuel [hydrogen] to support microbial chemosynthesis."
Even more interesting, perhaps, is that the results suggest that an additional mechanism—the reaction of brine-derived nitrates with basaltic rock—could be a "previously unrecognized means for mobilizing nitrate from the surface soils . . . and returning it to the Martian atmosphere as nitrous oxide," Joye said.
The discovery of water has been the holy grail of numerous Mars missions over the years, and in 2009 the Mars Phoenix mission's cameras photographed on the legs of the lander what appeared to be liquid water. If ultimately confirmed—and growing evidence appears to be solidifying in favor of such an analysis—it would be the first time liquid water was detected and photographed outside the Earth.
Working in such a beautiful but unearthly area presents stern challenges to researchers, Joye said.
"It's a 40-minute helicopter ride over the McMurdo Sound just to get there," she said. "Once in the Wright Valley, we enter a tight enclosure with steep, rocky cliffs on both sides, and between them is Don Juan Pond. I believe it must be one of the most beautiful places in Antarctica."
"It has the kind of beauty that rock parks in Japan have," he said, "except this is made by nature."
Beauty aside, though, the team had to dress in sterile suits and masks and use sterile instruments for sampling to avoid possible contamination. They also collected the minimal amount of material necessary to achieve their research goals.
The discovery of the new mechanism opens numerous questions that must be studied, including the possibility that the process is taking place in other extreme Antarctic habitats or that it might contribute to nitrous oxide in temperate soils—a possible new clue to understanding greenhouse gases involved in global warming.
The most crucial result, however, may be in understanding how similar brine pools on Mars might work and whether they could support life.
Sam Fahmy | EurekAlert!
Sea ice extent sinks to record lows at both poles
23.03.2017 | NASA/Goddard Space Flight Center
Less radiation in inner Van Allen belt than previously believed
21.03.2017 | DOE/Los Alamos National Laboratory
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
23.03.2017 | Power and Electrical Engineering
23.03.2017 | Earth Sciences
23.03.2017 | Life Sciences