A geological phenomenon that made most of the Mediterranean species disappear 5.5 million years ago

2024/09/04 Galarraga Aiestaran, Ana - Elhuyar Zientzia Iturria: Elhuyar aldizkaria

• Eboluzioa
• Geologia
• Paleontologia
• Ekologia

About 5.5 million years ago, technical movements separated the Mediterranean and the Atlantic Ocean. At the same time, a gigantic salt store was formed under the Mediterranean. Scientists have known this since the 1970s. Now, the study of fossils before and after that geological change reveals that only 11 percent of the species survived and that up to 1.7 million years later, the abundance of previous species did not recover.

In fact, this tectonic movement caused dramatic changes in salinity and temperature, affecting all marine ecosystems: There were 779 endemic species ahead and only 86 species behind. Subsequently, with the reconnection of the Atlantic and the Mediterranean, the Atlantic species colonized the Mediterranean and there was a gradation in the diversity of species from west to east. In this sense, they have pointed out that this gradation "has remained until today". The study has been published in Science.