Coral and the algae that live inside them likely teamed up 160 million years ago, according to a new study published in the journal Current Biology. Both organisms form a symbiotic relationship, which means they need each other to survive. Though scientists have long known about that interaction, they previously believed it only dated back to around 60 million years.
The new study — which comes from a team of international researchers — changes that perception and shows reef algae has survived multiple extreme environmental changes throughout the millennia. That includes mass extinction events like the one that killed off the dinosaurs.
To get a better analysis on the small organisms, the team in the research looked at the diversity of algae species that live in coral. That revealed the group Symbiodinium has many more members than previously thought.
In addition, DNA analysis revealed the organisms likely began their relationship with coral during the Middle Jurassic period long before the dinosaurs died off.
“Our recognition of the true origin of those microbes that give corals life is a major revelation,” lead author Todd LaJeunesse, a professor at the University of Pennsylvania, told BBC News. “They are way older than was previously estimated. Meaning that [this partnership has] been around for a hell of a long time!” added the Pennsylvania State University researcher.
This is some of the first in-depth analysis on reef and coral resilience, and it could have large implications moving forward. Not only does it shed more light on the organisms, but it also shows they may be able to survive hotter waters.
There is no doubt that climate change is a problem that could lead to collapsing ecosystems, but this gives the reefs a bit more hope than they previously had.
The team next hopes to study other Symbiodinium species more closely to compare their genomes and analyze their thermal tolerance to see how they will fare in the future.
“Until now, much research on these algae attempted to compare apples to apples, but we now know that often we are comparing apples to oranges considering how divergent some of these species are,” said John Parkinson, a researcher at Oregon State University, according to Phys.org. “Until now, much research on these algae attempted to compare apples to apples, but we now know that often we are comparing apples to oranges considering how divergent some of these species are. Our work will help researchers to think more objectively about the comparisons they are making in experiments.”