Scientists have discovered that a type of algae known for promoting resiliency among coral reefs is invasive in the Caribbean and potentially harmful to coral health.
When corals are stressed by warming temperatures, or other extreme changes in their environment, they tend to react by bleaching, or turning white. But there’s actually a type of algae, Symbiodinium trenchii, that can help the corals survive in stressful conditions. Researchers recently discovered that in the Caribbean, this species of algae is invasive and likely traveled from the Indo-Pacific Ocean. S. Trenchii was first noticed in the Caribbean in the early 90s. The scientists who authored the study came to this conclusion when they saw there was low genetic diversity among the species in the Caribbean, compared to their comrades in the Indo-Pacific.
Tye Pettay, a post-doctoral researcher at the University of Delaware, says this algae species’ ability to prevent bleaching is a mystery among scientists. But that’s housed in a much larger mystery of how algae and coral interact with each other.
“It’s a very big black box in the coral community," said Pettay.
Yet this invasive algae not entirely beneficial for the Caribbean coral reefs. The study has shows that the algae can stunt their growth, slowing it sometimes as much as 50 percent compared to other corals that don’t provide residence to this species.
“You see that the symbiant is not giving as much nutrients to the coral, so the coral grows at a slower rate," said Pettay.
Pettay added that stunted corals can lead to shrinking reefs, which could turn into major habitat loss for many vital marine species. He and his colleagues are currently conducting research to better understand how the algae operates to prevent bleaching, as well as stunt growth among corals.
Their paper on the invasive algae in the Caribbean was published this week in the journal Proceedings of the National Academy of Sciences.
