Astrobiologists are looking for traces of extraterrestrial life on our neighboring planet Mars in the form of fossil remains of microorganisms, and in a new study, scientists propose using the chemical element vanadium in combination with Raman spectroscopy to detect such remains.
The method of Raman spectroscopy makes it possible to discern the carbon backbone of a biological cell, however, false determinations are possible when carbonaceous materials formed in other natural processes, for example, in hydrothermal springs, are taken for the remains of biological cells. In a new research paper, Craig Marshall, associate professor of geology at the University of Kansas, USA, and his colleagues propose a way to reduce the likelihood of such false determinations using X-ray fluorescence spectroscopy, which allows to determine the elemental composition of rocks. The authors suggest using this method to search for the element vanadium, the distribution of which in the remains of biological cells is close to the distribution of carbon.
In the center of the chlorophyll molecule of living cells, magnesium is contained, which plays the role of a complexing agent. With the gradual immersion of biological material deep under the surface of the planet, magnesium is replaced by vanadium, and thus vanadium ends up in the remains of biological cells, explained Marshall.
Marshall and his team have successfully tested their proposed method on the earth's fossil remains of microorganisms called acritarchs. Scientists believe that their method of searching for traces of life on Mars can be implemented as part of NASA's new Mars 2020 project, which involves launching a new one to the Red Planet by 2020.
The work was published in the journal Astrobiology.
