Researchers Find Ancient Fossils with Oldest Biomolecules Ever Discovered

It turns out that complex organic molecules can indeed survive fossilization, debunking the long-held theory that they couldn't. The 350-million-year-old remains of aquatic sea creatures have been uncovered by researchers and have made scientists question the preservative nature of fossilization.

Millions of years ago, aquatic creatures known as crinoids made their homes in what is now known of Ohio, Indiana. Instead of dry land, though, they rested on the bottom of a massive inland sea. Their spindly bodies and feathery arms were adept at snatching particles from the waters in order to feed themselves. Known more commonly as the "sea lily" today, these animals look almost plant-like and "root" themselves to the ocean floor.

Yet the short lives of these crinoids were soon to come to an end. The ones that researchers found were possibly buried alive in storms during the Carboniferous Period. The specimens were quickly isolated from the water above them as they were covered by fine-grained sediment. Their porous skeletons eventually filled with minerals, though some of the pores containing organic molecules were sealed intact. Now, researchers have extracted the molecules from these crinoid fossils in the laboratory.

The researchers, Ohio State University geologists, were able to determine that different species of crinoid contained different molecules. Their findings, which will appear in the March issue of the journal Geology, are the first of their kind to find intact molecules after fossilization.

Lead author, Christina O'Malley, ground up small bits of the fossils by dissolving them in a solution. This allowed her to isolate the molecules. She then injected the sample of the solution into a gas chromatograph mass spectrometer, a machine that vaporized the solutions so that a magnet could separate individual molecules. Then, computer software identified the molecules.

The molecules themselves appeared to be aromatic compounds called quinones. These compounds are also found in modern crinoids, and sometimes function as pigments or as toxins in order to discourage predators.

The next step for the researchers is to identify the exact type of quinone molecules that they found, and to find out as much information as they can about the individual species using the molecules. Since these molecules are not DNA, they're not as useful when it comes to defining evolutionary relationships. However, they're still useful to researchers as a means to understand this ancient species. The findings show that fossils can indeed possess valuable biological material, even after 350 million years.