Ancient tiny fossils from Australia may carry evidence of great power: the ability to make oxygen through photosynthesis.
Cyanobacteria’s invention of photosynthesis is responsible for the oxygen in Earth’s atmosphere. “So they’re a big deal,” says Woodward Fischer, a geobiologist at Caltech who was not involved finding the thylakoid membranes. And “this is the kind of information that I thought we were not going to be able to pull out of fossils,” he says.
Most fossils preserve mineralized tissues such as bone or shells, but bacteria don’t contain such mineral structures. These fossils are “just compressions of carbon” squished into mud, Fischer says. To find the bacteria preserved is impressive enough, but the new fossils reveal complex structures inside the microscopic bacteria. “It suggests this kind of future where we might be able to pull more information, more cell biology and morphological detail out of these minuscule fossils,” he says.
Researchers already had indirect evidence from genetics and chemical studies that cyanobacteria had developed thylakoids by the time these fossilized bacteria lived, says Patricia Sanchez-Baracaldo, an evolutionary microbiologist at the University of Bristol in England (SN: 9/8/15). Still, exactly when the structures evolved is hotly debated (SN: 3/2/17). So it’s exciting to see fossil evidence of such old thylakoids, says Sanchez-Baracaldo, who was not involved in the work. “Any evidence that you have from that time period is important because the fossil record is really very sparse.”
2024-01-03 11:38:39
Link from www.sciencenews.org