Published : Tuesday, February 26, 2019 | 5:47 AM
Astrobiologist Laurie Barge and her team at Jet Propulsion Laboratory Pasadena have recreated some of the first steps of life in laboratory.
The team has run experiments showing how the ingredients for life could have formed deep in the ocean four billion years ago.
Barge from the NASA Astrobiology Institute’s Icy Worlds team at JPL, is working to recognize life on other planets by studying the origins of life here on Earth. Research focuses on how the building blocks of life form in hydrothermal vents on the ocean floor.
Hydrothermal vents were recreated in the lab, miniature seafloors, by filling beakers with mixtures that mimic Earth’s primordial ocean. The lab-based oceans now act as nurseries for amino acids, organic compounds that are the building blocks of life.
“Understanding how far you can go with just organics and minerals before you have an actual cell is really important for understanding what types of environments life could emerge from,” said Barge, the lead investigator and the first author on the new study, published in the journal Proceedings of the National Academy of Sciences. “Also, investigating how things like the atmosphere, the ocean and the minerals in the vents all impact this can help you understand how likely this is to have occurred on another planet.”
Natural chimneys form around these hydrothermal vents on the ocean floor and release fluid heated below Earth’s crust. When these chimneys interact with seawater, they create an environment in the constant flux necessary for life to evolve and change. This dark, warm environment, fed by chemical energy from Earth, may be the key to how life could form on worlds farther out in the solar system, far from the heat of the Sun.
“If we have these hydrothermal vents here on Earth, possibly similar reactions could occur on other planets,” said JPL’s Erika Flores, co-author of the new study.
Barge and Flores used ingredients commonly found in early Earth’s ocean in their experiments, combining water, minerals and the “precursor” molecules pyruvate and ammonia, which are needed to start the formation of amino acids. They tested their hypothesis by heating the solution to 158 degrees Fahrenheit – the same temperature found near a hydrothermal vent – and adjusting the pH to mimic the alkaline environment. They also removed the oxygen from the mixture because early Earth had very little oxygen in its ocean.
“We’ve shown that in geological conditions similar to early Earth, and maybe to other planets, we can form amino acids and alpha hydroxy acids from a simple reaction under mild conditions that would have existed on the seafloor,” Barge said.
Barge’s creation of amino acids and alpha hydroxy acids in the lab is the culmination of nine years of research into the origins of life. This is the first time her team has watched an environment very similar to a hydrothermal vent drive an organic reaction.
The team’s line of research is important for scientists studying other worlds in the solar system and beyond that may host habitable environments.
By understanding how life could start in an ocean without sunlight, scientists might begin designing future exploration missions and experiments that could dig under the ice to search for evidence of amino acids or other biological molecules.
“We don’t have concrete evidence of life elsewhere yet,” Barge said. “But understanding the conditions that are required for life’s origin can help narrow down the places that we think life could exist.”
For more information on the study, visit www.astrobiology.nasa.gov.
To learn more about Laurie Barge’s team at JPL, visit www.icyworlds.jpl.nasa.gov.