Scientists often believe that life can adapt to even the harshest of environment especially microorganisms. However, a recent study found out that there is one place here on Earth with conditions that are not suitable to hold any form of life.
NOT A FORMULA FOR LIFE
The study, which was conducted by scientists from Europe, spearheaded by Purificacion Lopez-Garcia of the French National Centre for Scientific Research, brings the spotlight to the hellish landscape of Dallol in Ethiopia where a volcanic crater can be found with an enormous amount of salt and toxic gases are abundant that emanate in the air. Here, the water is always at boiling point in the midst of hydrothermal activity. During the winter, the temperature would still reach 45 degrees Celsius, and the pH level would reach negative due to its acidity.
The findings in this study disprove earlier research which claims that microorganisms can survive extreme environments similar to that of Dallol. This previous study also proposed that these extreme environments are kind of similar to what Mars used to be.
In the study, which was published in Nature Ecology & Evolution, Lopez-Garcia explains, "After analyzing many more samples than in previous works, with adequate controls so as not to contaminate them and a well-calibrated methodology, we have verified that there's no microbial life in these salty, hot and hyperacid pools or in the adjacent magnesium-rich brine lakes." She also explains that what exists in the crater and the saline canyons, and hydrothermal site, is a diverse group of primitive microorganisms that likes salt. However, these microorganisms are not present in the actual hypersaline pools or in the Black and Yellow lakes around Dallol where magnesium is very much abundant. This absence of microorganisms in certain areas are noted despite the fact that factors such as the wind and human activity is rampant.
To obtain the results for this study, Lopez-Garcia and her team completed various methodologies such as the massive sequencing of genetic markers to be able to detect, correctly identify, and classify microorganisms and microbial culture attempts. The team also conducted fluorescent flow cytometry for them to identify individual cells of the microorganisms as well as conducting a chemical analysis of brines, and scanning electron microscopy combined with X-ray spectroscopy.
NO ROOM FOR CONFUSION
Puri Lopez-Garcia also clarifies that there are some silica-rich mineral precipitates in Dallol that may look like microorganisms under a microscope, so careful and thorough analysis is certainly needed. She explains, "in other studies, apart from the possible contamination of samples with archaea from adjacent lands, these mineral particles may have been interpreted as fossilized cells, when in reality they form simultaneously in the brines even though there is no life."
For the authors, this study can help in demanding caution when interpreting biosignatures here on Earth or on other planets. The scientists behind this study warn that identification of life should not only rely on the obvious cellular aspect of a structure. Lopez-Garcia also explained that their study presents evidence that there are places on Earth that are sterile even though there is water present. Lopez-Garcia explains that this also disproves the accepted theory of water being the telltale sign of life—meaning regardless if water is present on a planet or not, it does not mean there is a life.
