WHAT ARE CORALS TRYING TO TELL US?

By: BCI (Based on “Evolutionary Traits that Enable Scleractinian Corals to Survive Mass Extinction Events.” 2020 )

According to an article published on Scientific Reports, stony corals (scleractinians) are in survival mode, as if preparing for a mass extinction. Scientists analyzed fossils from the mass extinction of 66 million years ago of 839 threatened species of these corals and when comparing them with current specimens they found alarming similarities.

Stony (scleractinia) corals are important engineers of the underwater habitat, whose skeletons form the basis for the highly diverse (and increasingly threatened) ecosystems of coral reefs. For their part, the skeletons of fossil corals also present a rich record that allows a paleontological analysis of their origin, which can date back to the Triassic (approximately 241 million years ago). Although many invertebrates disappeared in the last great mass extinction (66 million years ago), several scleractinian corals survived.

That is why scientists from New York, California, Israel, England and Germany analyzed fossils of stony corals from that last mass extinction and compared them with current corals. After analyzing 839 species from the IUCN Red List of Threatened Species, they discovered that the most surviving species present the same characteristics found in fossils: migrations to depths greater than 100m, formation of small colonies with a cosmopolitan distribution, absence of symbiotic relationships with other species, and greater resistance to bleaching. While those corals in shallow areas that maintain their usual behaviors are decreasing in abundance and diversity.

One of the researchers, the marine biologist David Gruber, said in an interview for Newsweek: "When we finally saw the result, the hair on the back of my neck stood on end. It was like, my God, the corals are doing exactly what they did back then."

Other recent studies indicate that the climate crisis threatens to wipe out most of the world's corals by 2100, due to rising ocean temperatures that cause coral bleaching or spawning problems. Yet as dramatic as the extinction crisis is, on a human timescale it is barely visible. "It's like watching a car crash in slow motion," Gruber said.

According to Natural History, the earth has experienced five major mass extinction events ("The Big Five") since the Cambrian period, each resulting in the loss of more than three-quarters of the species' biodiversity over an interval of geologically short time.

And this study, comparing today's threatened species with those that disappeared along with the dinosaurs, offers us just a glimpse of what many biologists have begun to call the sixth extinction.

The hope for life on the planet that some scientists observe from this analysis is that in the end not everything is completely extinguished, since some species resist by adapting and recovering over time; but we must remember that humans in our order of primates are not so flexible. We are even more delicate and fragile than other species.

The survival of our species depends on us making better decisions that protect the delicate ecosystems on which our lives depend. For this, we must share adequate information, based on solid scientific research, that allows us to understand the importance of changing course.

Will we be on time?