Corals And Algae Have Existed Much Longer Than Once Thought, New Study Suggests

A recently published paper suggests that the relationship between corals and algae has been in place for far longer than once believed, with both organisms possibly surviving the mass extinction event that killed the dinosaurs.

According to a report from BBC News, corals and algae are organisms that are known to depend on each other for survival. This symbiotic relationship, as it is known, was once thought to have started approximately 60 million years ago, but in a study published in the journal Current Biology on Tuesday, a team of researchers placed the start of the relationship about 100 million years prior to that.

With the help of DNA analysis, the researchers examined the Symbiodinium genus and confirmed that it was a diverse family of algae, while also discovering that the group had more individual species than originally believed. According to the study, Symbiodinium might have started coexisting with corals and evolving into different species up to 160 million years ago, during the Middle Jurassic Period, when dinosaurs still ruled our planet and were close to 100 million years away from their eventual extinction.

“Our recognition of the true origin of those microbes that give corals life is [a] major revelation,” said Pennsylvania State University professor and study lead author Todd LaJeunesse, in an interview with BBC News.

“They are way older than was previously estimated. Meaning that [the partnership between corals and algae] been around for a hell of a long time!”

As explained by Phys.org, the symbiotic relationship between corals and algae is the “foundation” of the coral reef ecosystem, as the former organisms are made up of polyps, or animal hosts that carry microscopic algae in their cells. Thanks to this partnership, the polyps receive their food supply from the algae and reciprocate by protecting and nourishing the tiny organisms, which are also known as zooxanthellae.

Prior to the new study, scientists had categorized multiple families of algae, or clades, into one single genus. However, study co-author John Parkinson, a postdoctoral scholar at the Oregon State University College of Science, said that his team’s research proves that Symbiodinium consists of “at least 15” genera that might include up to several thousands of different individual species.

According to LaJeunesse, the new study could have vital implications as far as protecting corals and algae from the harmful effects of climate change. He told BBC News that the research proves how the organisms are “incredibly resilient” and likely to last for “a long time,” but warned that there is also a possibility that climate change could accelerate their decline.

To that end, LaJeunesse’s team is planning to dive deeper into their research by studying individual species of Symbiodinium and how they interact with various coral species and weather variables, in an effort to learn how the genus could hold up and respond to the ongoing problem of climate change.

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