Photo by Stephen Frink

by Julie Z. Russo

Coral reefs are among the most fragile, heavily impacted, and rapidly disappearing ecosystems on Earth. It is during reproduction and larval development that the corals are most vulnerable. The young, defenseless coral larvae in the plankton are most sensitive to pollution and predation. Yet these stages offer the greatest potential for developing safe and relatively inexpensive new methods of biological control.

In a study by NOAA's Undersea Research Program's (NURP) Caribbean Marine Research Center, molecular biologists Daniel and Aileen Morse of the University of California at Santa Barbara discovered the signal molecules that cue coral larvae to settle and metamorphose on specially favorable habitats where the corals can grow well. The researchers are now working to incorporate these natural signal molecules into artificial surfaces that act like a kind of "larval flypaper," inducing the larvae to settle and metamorphose on these recruiting surfaces. This technology could be developed to provide a low-cost and reliable means for production, reseeding, and restoration of corals. The results of their work should make production of coral by aquaculture a feasible alternative, thereby reducing harvesting pressure on natural stocks. The Morses' discovery of the signal molecules that control the settlement of abalone and other shellfish larvae have led to innovative new technologies for low-cost aquaculture and reseeding programs, forming the basis of commercially successful new aquaculture industries in the United States and other countries.

This research also has the potential for important medical applications since the molecules that control coral recruitment might have an analogue to human signal molecules that regulate development of human cells. Daniel Morse became interested in the evolution of marine signaling systems while he was a professor at Harvard Medical School. The chemical sensing mechanism that cues coral larvae to settle has evolved in mammals as well, but for different purposes. By isolating coral signal molecules, Morse might be able to identify the signal molecules in the human body that activate the body's immune system against disease or that regulate gene expression.