It’s been called the greatest synchronized sex show on earth: A few nights after the November full moon, corals release millions of pink bundles of egg and sperm that drift to the surface in an enormous upside-down blizzard, resembling what it must be like on the interior of a shaken snow globe. Only the very lucky few have been witness to this mass spawning event in the waters of Australia’s Great Barrier Reef, but on Friday, May 2nd, attendees of the Mill Valley Public Library’s First Friday event, “Sex on the Coral Reef,” will receive a front-row seat to this exotic and rarely seen world. Using gorgeous images, marine biologist Erika Woolsey will provide an inside look at coral reef ecosystems, including the annual spectacle that keeps divers and scientists traveling from around the globe.

A native of Marin, Woolsey has been living in Australia, where she is currently finishing her PhD with the Australian Research Council Centre of Excellence for Coral Reef Studies. Her area of expertise is coral reproduction, and her research seeks to understand how warming oceans will affect the ability of coral reefs to replenish themselves and recover from disturbance, which is especially important in changing oceans. As she shows photos and shares her experiences Down Under and underwater, Woolsey will discuss the threat that climate change poses to the long-term future of coral reefs.

Often referred to as “rainforests of the ocean”, coral reefs are diverse ecosystems that cover less than 1 percent of the sea floor, yet support about 25 percent of marine species. These fragile environments are dependent upon healthy oceans to survive, and unfortunately, about 60 percent of the world’s coral reefs are under immediate threats from climate change and localized human disturbances.

“Coral spawning is truly an incredible natural phenomenon,” says Woolsey. “It’s been happening for millions of years all over the world, and no other sex event in the Animal Kingdom is this well organized. Not only is coral spawning fascinating and visually stunning, it allows coral populations to persevere. Without baby corals, we wouldn’t have adult corals that build important ocean habitats. Contemporary climate change and human disturbance are severely impacting these ecosystems, so it’s becoming more and more important to understand how young coral react in a changing ocean.”

The 411: Part of the Mill Valley Public Library’s ongoing series of First Friday events, Sex on the Coral Reef takes place May 2 at 7 pm in the Library’s Main Reading Room. A wine reception for pre-registered guests will begin at 6:30 pm. This event is free, but registration is recommended. First Friday events are open to adults and high school students only. To register, call 415-389-4292, ext. 3 or sign up online at

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