The type of algae known as dinoflagellates are valuable for improving the health of corals in warming waters, and now, researchers from Rice University have discovered that they reproduce via sex, meaning that algae sex could be critical for the survival of coral reefs. 

The algae reproduce by either splitting in half or through sex, so researchers are working on breeding strains of dinoflagellate symbionts that better serve their coral partners. These symbionts help coral by converting sunlight into food. They also give corals their signature vibrant colors. While corals only reproduce once a year, dinoflagellates produce a new generation every couple of months. So focusing on algae, rather than coral, could actually be a more time-efficient way to boost the resiliency of corals.

The researchers observed corals in Mo’orea, French Polynesia and by using confocal microscopes, were able to identify sexual reproduction in the algae. As sexual reproduction involves DNA from both parents, it allows for more rapid genetic adaptation than divided offspring which just have the cloned DNA of a single parent.

“These efforts are ongoing to try to breed corals, symbionts, and any other partners to make the most stress-resistant colonies possible,” said marine biologist Adrienne Correa. “For coral symbionts, that means growing them under stressful conditions like high temperatures and then propagating the ones that manage to survive.”

Once they establish more resistant algae strains, the researchers plan to breed coral hosting the new symbionts and then seed those in natural environments where they will hopefully be more resistant to a changing climate.

Source study: Scientific Reports – Direct evidence of sex and a hypothesis about meiosis in Symbiodiniaceae