Sex on the Reef

When some people think of coral, they imagine chunks of rock resembling the human brain or delicately branching structures of exquisite detail and fragility. For others, coral brings to mind colorful jewelry, strung as beads of white and pink. These are all the calcified secretions of a vibrant community of microscopic animals that make their homes upon the structures that they create, animals that reproduce sexually in their struggle to survive. And struggle they must, our tiny heroes, because only one out of many thousands of fertilized eggs survives and may take hundreds of years to grow as big as the specimens that dazzle in a seaside souvenir shop.

In the best of circumstances, our reefs teem with life, supported by a luminous community of coral species responsible for both creating the structural backbone of the reef and mediating the cycle of life within it. Cyanobacteria living symbiotically with the corals extract nitrogen from seawater and convert it to a form that is nutritive to plants, and in turn moves up the food chain of the animal population.

While coral reefs cover less than 0.1% of the ocean floor, they support astounding biodiversity that accounts for at least a quarter of all marine species, including at least 4000 species of fish and possibly millions of distinct species ranging from microorganisms and plants to crustaceans and sponges. A quarter of all fish harvested for human consumption come from reef environments. Aside from their crucial contribution to our food source, reefs provide a physical barrier that protects coastlines from the erosive effects of waves and the destructive force of storms, buffering coastal communities against the threats posed by rising sea levels and increasingly turbulent weather. Corals have also been a source of naturally occurring medicinal compounds.

These aquatic colonies and the reefs that support them have come under pressure that now threatens their existence and ultimately ours. Much of this pressure arises from human activity, including coastal development, dredging, pollution, fishing, mining for building materials and...yes...souvenirs, oil spills, even sunscreen! And the effects of manmade global warming include rising temperatures and acidification, both of which cause coral bleaching, reducing reefs to lifeless stone. Even without the need to adapt to drastically changing conditions, the slow growth of these organisms makes it impossible for them to replenish themselves without help. And marine scientists have spent years trying to raise corals with which to reseed reefs.

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Enter Mote Tropical Research Laboratory in the Florida Keys and Dr. David Vaughan, a weathered looking biologist with a bushy rust and salt beard that frames an animated smile underscoring his enthusiasm for educating visitors about corals. A pivotal moment of serendipity combined with mindful observation and inspiration led to a discovery that has accelerated the rate of coral growth in the laboratory by orders of magnitude. While corals tend to repair themselves by growing faster when broken, they grow many times faster when fractured into tiny fragments. Dr. Vaughan first observed this effect as the result of a laboratory accident and has since utilized it as a cultivating technique that has increased new colonies from tens to many thousands and is expected within the next several years to create hundreds of thousands of colonies that will be planted in the wild and are expected to rebuild reefs in a fraction of the time that nature once required.

Even more exciting is the assist that Dr. Vaughan and his team is giving to natural selection. By creating microenvironments with gradations of both pH and temperature, they have managed to simulate a range of possible conditions that might occur decades from now and select coral cultures best adapted to the most stressful conditions that we can predict, while still preserving biodiversity.

All life as we know it would be threatened by the extinction of the corals. While we may worry more about international conflict and terrorism as threats to our existence, the coral nurseries at Mote may well be ground zero for the survival of our species.