Curiosity found new organic molecules on Mars

Back in 2017, as the Curiosity rover was collecting a dirt sample from Mars’ Bagnold Dune, the space vehicle experienced an unexpected malfunction: Its drill suddenly went out of service. Rather than scrap the mission, NASA scientists tweaked the sampling technique such that the rover placed the dirt sample into cups containing a chemical cocktail, rather than empty cups. Surprisingly, this type of sampling—known as a wet sampling experiment—helped scientists identify organic molecules that had not yet been seen on the red planet.   

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The Curiosity rover has been searching for biosignatures, or indicators of previous life on Mars, since it landed on the planet in 2012. Today, Mars is mostly made up of dirt, dust, and gas, but long ago it may have been home to lakes, rivers, and microbial life. The sample Curiosity collected from the Bagnold Dune on Mars did not have biosignatures on it, which is evidence of past life, but it did have organic molecules that had not been seen previously on the planet: ammonia and benzoic acid. 

These organic molecules are good indicators of biosignatures, which are chemicals that could have come from past life on Mars. But more than that, they also indicate that this method of collecting samples is promising. The wet chemistry experiment conducted was published on Monday in a study by the NASA team behind it in the journal Nature Astronomy. 

Organic materials, including thiophenes, benzene, toluene, and small carbon chains have previously been found on the Red Planet, coming from sedimentary samples. These past compounds were found using Curiosity’s specialized ovens that work to heat sediment and release these molecules. Ammonia and benzoic acid have never been found before with this method, though. In the wet experiment, Curiosity dumped the dirt into a mix of chemical reagents which triggered a chemical reaction that allowed researchers, back in the lab, to figure out what molecules were present.  

Researchers still need to figure out where and how exactly these molecules came about. The study indicates that the molecules could stem from geological processes on the planet, but could also potentially be indicators of past habitability. The dune where the sample was collected sits in Gale Crater, a spot on Mars suspected to have previously been filled with water, a good spot to look for signs of former life.  Researchers are awaiting the launch of the European Space Agency’s ExoMars expedition to have more samples to work with. 

In the meantime, this unexpected find helps put together a clearer understanding of the history of Mars, as bit by bit, scientists continue to uncover the Red Planet’s secrets.

Scientists Successfully “Wake” Microbes That Had Remained Dormant for 100 Million Years

The microbes belong to ten different groups of bacteria that entered an energy-saving state when the dinosaurs roamed the Earth.

Scientists have successfully managed to wake a series of microbes that had remained “asleep” for at least 100 million years. Moreover, the microbes that existed during the dinosaurs’ time have shown traces of growth in the latest studies.

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A team of scientists in the US and Japan says that these prehistoric microorganisms began to grow and divide despite entering an energy-saving state when dinosaurs were still walking on Earth.

The microbes belonged to ten different bacteria groups and were recovered from sediments mined in 2010 at the bottom of the South Pacific Gyre, one of the most deserted parts of the ocean in terms of nutrients.

“Our results suggest that microbial communities widely distributed in organic-poor abyssal sediment consist mainly of aerobes that retain their metabolic potential under extremely low-energy conditions for up to 101.5 million years,” wrote researchers in their study.

To obtain samples of the maximum possible depth, they drilled wells of up to 100 meters in the seabed at 5,700 meters below the surface.

The researchers, led by geomicrobiologist Yuki Morono of the Japan Marine Science and Technology Agency, incubated the sleeping microbes for 557 days in a laboratory.

Carbon and nitrogen sources such as ammonia, acetate, and amino acids were supplied to see if they subsequently succeeded in removing them from their torpor.

“It is surprising and biologically challenging that a large fraction of the microbes revived after being buried and trapped for so long in conditions of extreme nutrient and energy deficiency,” admits Morono.

Microbes are aerobic — they require oxygen to live — and oxygen was present in the sediment samples.

According to the researchers, this means that if sediments accumulate gradually on the seafloor, at a rate not exceeding a yard or two every million years, oxygen can remain present and allow these microorganisms to survive for extraordinary periods.

“I was skeptical at first, but we found that up to 99.1% of microbes in sediments deposited 101.5 million years ago were still alive and able to grow,” says study co-author Steven D’Hondt of the University of Rhode Island.

“Maintaining a physiological capacity for 100 million years in starving confinement is an impressive feature. First, however, we want to understand how these ancient microbes evolved, if at all.

This study shows that the subsoil is an excellent location to explore the limits of life on Earth, explain the researchers.

The paper describing the incredible characteristics of the microbes has been published in the Journal Nature Communications.

This is a great achievement since direct evidence of microbial cells’ physiological nature, and survival status in this highly energy-poor setting is poorly documented.

In addition to proving how resistant some microbes on Earth are, the recent study helps us better understand the possibility of similar microbes existing on other planets or moons in our solar system.

Mars, for example, was likely a planet very similar to Earth in the past.

Although there is currently no evidence of present life on Mars, new exploratory missions of the red planet could help reveal whether such microbes could survive beneath the surface of Mars as well.