About 200 million years ago there was a great mass extinction that affected more than half the species that inhabited our planet. During this event , amphibians, reptiles and a good number of marine animals disappeared . Although the causes of this collapse of biodiversity, which occurred at the end of the Triassic period, are not known for sure, geological and paleontological records point to a change in global climate.
Corals are very vulnerable organisms to these large variations in environmental conditions. Just as today’s colonies are severely threatened by climate change, during the Triassic-Jurassic mass extinction reefs were hit hard by fluctuations in ocean temperature and acidity. After this great extinction, it took more than 20 million years for corals to recover.
A team from the University of Montana, in the USA, studies precisely this recovery. To do this, they analyze the fossils found in the rocks of the New York canyon in Nevada. This area of the desert is rich in sedimentary rocks that were deposited at the Triassic-Jurassic border, and therefore offers a perfect environment to find more clues that allow scientists to unravel the mysteries of the mass extinction of species that occurred in this period.
The first survivors
The researchers, who publish their results in the Geological Society of America’s GSA Today magazine, have found in this region the first coral fossils that appeared after the Triassic-Jurassic mass extinction event. These corals belong to the Stylophyllidae family and, according to the authors of the work, “they are solitary and tend to live under thick mud, a characteristic that may have helped their survival during this tumultuous time. Another possibility is that they had migrated from other areas of Pangea ”. In any case, they were the first representatives from which corals could recover and diversify over millions of years.
In addition to corals, the team mentions other species of bivalves, gastropods and ammonites in their work, which complete the description of the landscape of fauna after mass extinction. A study that will not only help to understand what happened at that time, but “also offers valuable information to understand the danger faced by today’s coral reefs,” the researchers have clarified.
