Friday July 22, 2022
Hakai Magazine —
It’s relatively well known that most fully functioning corals one finds dotting colorful coral reefs are a symbiosis between a coral (the animal itself) and the microscopic algae that dwell within it. This duo forms the physical foundation of coral reefs, where one-fourth of Earth’s marine species reside. But what is much less well known is how corals get their algal partners.
Spawning corals begin their lives flying solo as free-living larvae without algal partners. They’ll eventually acquire their algae from the environment. But where do those algae come from? Scientists aren’t really sure.
Adrienne Correa, a marine biologist at Rice University in Texas, has devoted her career to studying corals and their symbionts, and she has an idea about the source of at least some of corals’ symbionts: fish poop.
In recent research, Correa and her team showed that the feces of coral-eating fish are loaded with algae species that can establish symbiotic relationships with corals. The scientists have yet to fully connect the dots, however, and show that either adult or larval corals pick up symbionts from fish feces. But the fact that sea anemones, a closely related organism, get their algae this way gives the idea a boost.