Brian Hynek
The highlands of northwestern Argentina are home to salt lakes that are home to giant stromatolites, layered rocks made by microbes that represent the oldest fossil evidence of life on Earth.
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Scientists have discovered a previously hidden ecosystem with a vast lagoon system on the salt flats Huge stromatolites in Argentina’s arid plateau Puna de Atacama could offer a glimpse of the earliest life on Earth and even life on Mars, according to a new study.
Stromatolites are layered rock It is produced by the growth of blue-green algae, or cyanobacteria, through photosynthesis. This structure is believed to be one of the oldest ecosystems on Earth. According to NASA, represents at least the oldest fossil evidence of life on Earth 3.5 billion years ago.
“These certainly resemble some of the earliest megafossils on Earth, and are in a type of environment that is truly unusual on modern Earth.” Brian HynekProfessor He contributed to the documentation of ecosystems in the Department of Geological Sciences at the University of Colorado Boulder. “They are a window into the distant past, into what life was like on Earth 3.5 billion years ago.”
Ancient giant stromatolites were widespread during Earth’s Precambrian period. 4.6 to 541 million years ago, but now it is sparsely distributed around the world. The most developed areas are the Bahamas and the Shark Bay region of Western Australia, the nonprofit conservation organization said. bush heritage australia.
While modern stromatolites are relatively small, ancient stromatolites once grew up to 20 feet (6 meters) tall and 16 to 22 feet (5 to 7 meters) wide, Hynek said. Beneath the surface of the Puna de Atacama lagoon, recently discovered stromatolites measure 4.5 meters (15 feet) wide and several feet tall. According to the news release Graduated from the University of Colorado Boulder.
Brian Hynek
The newly discovered giant stromatolites in Puna de Atacama are mainly composed of the minerals gypsum and halite.
Although stromatolites tend to grow in alkaline conditions, the lagoonal system of Puna de Atacama is acidic. Stromatolites currently discovered are almost all carbonate rocks (made of limestone), but these structures are mostly composed of minerals. gypsum and rock salt (rock salt), Hynek said.
Hynek doesn’t know why the stromatolites are so large, but he suspects that inland ecosystems were left undisturbed for long periods of time, allowing them to grow unhindered.
Unlike modern stromatolites, ancient stromatolites grew during a time when there was a lack of oxygen in the atmosphere. In such situations, stromatolite microorganisms are used. anoxic photosynthesisThey do not require oxygen to convert light energy into compounds that support living cells.
“It’s spectacular to discover structures that appear to be biogenic (produced by living things) at this unusual altitude,” he said. Pieter VischerA professor of marine science at the University of Connecticut who has studied stromatolites extensively said in an email. “The big problem with this discovery, biogenic or not, is that they form in the presence of oxygen (in the current atmosphere), which was not present until 2.3 billion years ago. ”
Stromatolites live in an oxygen-rich environment, Hynek said. We believe that the layers further down the rock have little access to oxygen and are actively formed by microorganisms that use anoxic photosynthesis. This would make the structure similar to those found on ancient Earth.
Brian Hynek
The Argentine lagoons were first discovered through satellite imagery in April 2022.
Hynek discovered the lagoon system through satellite imagery in April 2022 while investigating another lagoon in northwestern Argentina. There were small stromatolites containing microorganisms that utilize anoxic photosynthesis.
“We don’t know if microorganisms are actively involved in the growth (of the newly discovered stromatolites). We think so. But we are conducting experiments to find out part of it. We haven’t done it yet,” Hynek said, documenting preliminary observations with microbiologist Maria Farias, co-founder of Punavio SA Environmental Consulting. “There’s a lot of work to be done. We’ve only just scratched the surface in discovering them.”
Hynek and Farias were scheduled to present their findings at the Geophysical Union’s 2023 meeting in San Francisco on Dec. 11, according to a news release.
If stromatolites are produced by microorganisms using anoxic photosynthesis, the discovery could provide insight into the possibility of life on ancient Mars, Hynek said.
“We have identified over 600 ancient lake on mars; There may have been an ocean as well. So it was more like Earth in its early days,” he said.Mr. Hynek also said Mineral gypsum and rock saltdiscovered in stromatolites in Argentina, and also present in salt deposits across Mars.
“If Mars evolved life through photosynthesis, this is the kind of thing we’re looking for (stromatolites). the kind of things we’re looking for” said Hynek, who is also a researcher at the University of Colorado Boulder Institute for Atmospheric and Space Physics.
“If we do find any fossils on Mars, this is our best guess as to what they might be, because these are the oldest in Earth’s rock record.”
Hynek said he hopes to return to the lagoon soon to conduct further research on stromatolites.
“Stromatolites on Mars? Quite likely, but no one knows. So far, there are no carbonates on the surface of Mars, but the search continues for possible signs of life. ,” Vischer said.