Chasing Coral is an ocean adventure film. It reveals the story of a team of photographers, scientists and other experts who discover and try to capture one of the world’s largest coral bleaching events. It took 3.5 years to make and features over 500 hours of underwater footage with submissions from over 30 countries.

UF/IFAS Extension will host a screening of Chasing Coral at the Jacksonville Regency Square Branch Library (9900 Regency Square Blvd, Jacksonville, FL 32225) at 6:30 pm on Thursday, November 5th. Sea Grant Agent Dr. Maia McGuire and Jacksonville University professor Dr. Dan McCarthy will lead a discussion following the film. This event is free and all are welcome.

What’s so special about corals?

Reef-building corals are very unusual animals because they live in partnership with a single-celled plant. The plants (algae referred to as zooxanthellae) live inside the coral animal’s cells. This symbiotic relationship has benefits to both partners. The plants share some of the sugars that they produce through photosynthesis with the corals. This helps the coral build its skeleton more quickly. The coral’s waste provides the plants with nutrients like nitrogen and phosphorus. The coral animal has stinging cells which probably provide the plant with protection from predators.

What is coral bleaching?

When corals are stressed, the partnership between the coral animal and its zooxanthellae can become disrupted. The most common stressor for corals is increased ocean temperature. A very small increase in maximum water temperature can cause this stress, especially if the warm temperatures continue for several weeks. Scientists are not sure exactly what happens, but stressed corals often lose their plant partners. In healthy corals, the color of the coral comes mostly from those plant partners. Without the plants, the coral will appear white. There may still be living coral animal tissue, but because that tissue is colorless, what we see is the white skeleton under the coral animals. We refer to this as coral bleaching. This is the phenomenon that Chasing Coral set out to document

Why are scientists interested in studying coral bleaching?

Corals that bleach can recover and become healthy again, but some fall victim to disease. When some or all of the coral tissue dies, the coral colonies quickly become overgrown by large algae. This changes the structure and functioning of the reef.

25% of the marine life in the ocean depends on coral reefs. We have lost 50% of the world’s corals in the last 50 years, mostly from disease and coral bleaching. The full environmental and economic value of coral reefs is estimated at $375 billion per year.

Less than 1% of people ever get to experience coral reefs in person. But many more people rely on coral reefs directly or indirectly. Coral bleaching events worldwide seem to be increasing. Scientists are concerned that coral reefs may not be able to survive in the coming decades.

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