Efforts to help struggling reefs see researchers working to prove that coral-eating fish spread symbiotic algae in their droppings.
It is widely known that most of the corals found on shallow reefs are symbionts with microscopic algae living inside them. The duo form the physical foundation of coral reefs, which are home to a quarter of the world’s marine life. Little is known, however, about how corals acquire their algal partners. Spawning corals start their lives drifting as free-living larvae without algal partners. They will eventually get algae from the environment, but where did this algae come from? Scientists aren’t sure.
Adrienne Correa, a marine biologist at Rice University in Texas who has been studying corals and their symbionts, has an idea for the source of at least some coral symbionts: fish poo.
In the latest study, Correa and her team showed that the feces of reef-eating fish are full of algae that can form a symbiotic relationship with corals. However, scientists have yet to fully connect the dots and show that adult corals or larvae really ingest symbionts from fish poop. But the fact that sea anemones, a closely related organism, access algae in this way, drives the idea. Correa and her team hope to demonstrate this link in experiments they will begin later this year at the Moorea Coral Reef Long-Term Ecological Study Site in French Polynesia.