160m year old coral algae symbiosis is being killed by this sunscreen

It would seem that the symbiotic relationship between coral and algae is 100 million years older than previously believed. That's what's said by a bit of new research published this week in the scientific publication Current Biology. This is the same relationship – and creatures – destroyed by a couple of popular sorts of sunscreen effectively banned in Hawaii just this year.

Algae live on coral, coral reefs are found in less than 1% of the ocean, one quarter of the known sea creatures live in and amongst coral reefs. If you've heard of "coral bleaching", you know it's essentially the death of coral reefs – the stressing out of coral to the point at which they expel their symbiotic partner algae, and everyone's the worse for it. Disconnected from algae, coral's animal hosts, polyps, do not provide nutrients and housing to algae, and algae don't provide food for the polyps.

New information on the algae part of this equation came to light this week in a research paper published in the scientific journal Current Biology. In the paper, it was suggested that the algae – and the symbiotic partnership algae has with coral – has been around and in action for 100 million years longer than previously widely believed. Where before this week it was common knowledge that these algae and their symbiotic relationship with coral was around for the past 60 million years, now it's suggested that it's been around for about 160 million years.

"Over all of those millions of years, partnerships [between algae and coral] have faced major hurdles and managed to bounce back," said Todd LaJeunesse of Penn State. "The fossil record shows today's reef-building corals, like the algae, arose around 160 million years ago. Finding that the origin of the symbionts corresponds to that of their hosts implies that the partnership was one of the major reasons for the diversification and success of modern corals."

This study focused on a genus of zooxanthella (algae) called Symbiodinium. This very common genus of algae was split up into seven individual "clades" in this research. These clades are equivalent to genera in the family called Symbiodiniaceae which, when split up, allow scientists to study each in more detail.

Through this process, researchers can better understand how algae and its symbiotic relationship with coral survived in so many different ways in the time it's existed on earth. This research both split up this Algae into seven individual bits, it allowed these researchers to "recalibrate the molecular clock for the group" and pinpoint the time at which it began to diversify – around 160 million years ago.

It was 160 million years ago that these algae began high-fiving coral in such a way that they both survived an amount of years far closer to the top dozen-or-so oldest animal species on our planet. The oldest remain cyanobacteria which is several billion years old, then (depending on who you ask) either Jelly Fish or sponges, both at between 500-600 million years old.

According to the paper, "these findings bring into alignment the ancient origin and success of reef-building corals with the evolution of the Symbiodiniaceae. They further imply that Symbiodiniaceae have persisted through tens of millions of years of Earth's history while enduring large and numerous environmental changes."

To learn more about the research mentioned above, have a peek at the paper "Systematic Revision of Symbiodiniaceae Highlights the Antiquity and Diversity of Coral Endosymbionts."This paper can be read as of this week, published August 9th, 2018, thanks to authors and researchers Todd LaJeunesse of Penn State, John Parkinson of Oregon State, and others. This paper is classified Open Access and can be found with code doi.org/10.1016/j.cub.2018.07.008 (URL) at Current Biology.