These researchers watched dead fish rot for 70 days—for science

Enlarge (credit: Aurich Lawson/T. Clements et al.)

Sometimes science can be a messy endeavor—not to mention "disgusting and smelly." That's how British researchers described their experiments monitoring dead sea bass carcasses as they rotted over the course of 70 days. In the process, they gained some fascinating insights into how (and why) the soft tissues of internal organs can be selectively preserved in the fossil record, according to a new paper published in the journal Palaeontology.

Most fossils are bone, shells, teeth, and other forms of "hard" tissue, but occasionally rare fossils are discovered that preserve soft tissues like skin, muscles, organs, or even the occasional eyeball. This can tell scientists much about aspects of the biology, ecology, and evolution of such ancient organisms that skeletons alone can't convey. For instance, earlier this year, researchers created a highly detailed 3D model of a 365-million-year-old ammonite fossil from the Jurassic period by combining advanced imaging techniques, revealing internal muscles that had never been previously observed.

"One of the best ways that soft tissue can turn into rock is when they are replaced by a mineral called calcium phosphate (sometimes called apatite)," said co-author Thomas Clements of the University of Birmingham. "Scientists have been studying calcium phosphate for decades trying to understand how this process happens—but one question we just don’t understand is why some internal organs seem more likely to be preserved than others."