Oric Lawson / T. Clements et al.
Science can sometimes be a messy endeavor – not to mention a “disgusting and smelly” activity. This is how British researchers described their experiments in which they observed seabass carcasses rotting for 70 days. In the process, they gained fascinating insights into how (and why) the soft tissues of internal organs could be selectively preserved in fossils. new page It was published in the Journal of Paleontology.
Most of the fossils are bones, shells, teeth and other “hard” tissues, but sometimes rare fossils are discovered that preserve soft tissues such as skin, muscles, organs, or even the eyeball. This can tell scientists so much about aspects of biology, ecology, and evolution of ancient organisms that skeletons alone cannot convey. At the beginning of the year for example Create researchers Highly detailed 3D model of a 365 million year old ammonite fossil Jurassic period by combining advanced imaging techniques, Discover the inner muscles that have not been observed before.
“One of the best ways to turn soft tissue into rock is to replace it with a mineral called calcium phosphate (sometimes called apatite)” Co-author Thomas Clements said: from the University of Birmingham. “Scientists have been studying calcium phosphate for decades to understand how this process occurs – but one of the questions we don’t understand is why some internal organs seem more likely than others.”
Specifically, the muscles, stomach, and intestines tend to “phosphate” more than other organs, such as the kidneys and gonads. There are two general hypotheses to explain this. The first is that different organs disintegrate at different rates, and the pH of some organs drops below the critical threshold of 6.4. When these organs disintegrate, they create a pH microenvironment that increases the likelihood of organ ossification. Different minerals can form in different areas within the same carcass.
The second hypothesis is that tissue biochemistry plays an important role. Specifically, a diffuse pH environment develops in the body cavity and persists until the carcass breaks.
According to Clement and others. , no previous research has focused on documenting pH gradients associated with decomposition of specific anatomical features as carcass degrades in real time; Previous experiments focused on recording off-carcass pH fluctuations. So the team decided to correct this shortcoming by conducting experiments with decomposing fish, documenting how the pH gradient changed over the course of two and a half months.
First, many mature European seabass were bought from a local fishmonger as quickly as possible (within 24-36 hours at most). Fish were kept on ice to slow decomposition but not frozen to avoid cell damage. They then placed pH sensors in different locations on the six seabass carcasses to target specific organs: the stomach, liver, intestines and supraaxial muscles. A fifth probe was used to monitor the pH value of the surrounding environment between 1 and 2 mm of the carcass.
T. Clements et al., 2022
