Ecosystem Tipping Points, Chemical Ecology, and the Continuing Death Spiral of Coral Reefs

Friday, April 25 at 4 p.m. to 5:30 p.m.

Marine Science Center, Bunker Classroom, 430 Nahant Road, Nahant, Mass.

Annual Riser Lecture

Presented by Mark Hay, Ph.D.
Professor and Harry and Linda Teasley Chair in Environmental Biology
Georgia Institute of Technology

Corals are in dramatic global decline, with losses of 80 to 90 percent in the Caribbean and 50 percent in the tropical Pacific over the last 3-4 decades. As corals decline, reefs “flip” to seaweed dominance. Marine Protected Areas (MPAs) are the major management tool for protecting adult corals and fishes, which can then theoretically export larvae to help degraded reefs recover. However, chemical cues from degraded reefs create a chemical barrier to larvae to arriving at these reefs.

Larvae and juveniles of three of three common corals and 15 species of fishes were strongly repelled by cues from degraded reefs that were heavily fished but attracted to chemical cues in waters from MPAs. Larvae were attracted to cues from specific corals and repelled by cues form specific seaweeds. In the field, coral larvae were present on degraded reefs, but refused to settle on the reef substratum there, despite commonly settling in adjacent MPAs. The positive effects of larval export from MPAs cannot be realized if coral larvae behaviorally reject degraded habitats based on chemical cues. Reefs dominated by seaweeds will continue their death spiral unless reefs are managed to produce cues that attract, rather than repel, larvae.

Please join us for our Annual Riser Lecture, celebrating the life and work of the Marine Science Center’s founding Director, Dr. Nathan “Doc” Riser.

Posted in Biology, Marine and Environmental Sciences