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Chasing Coral Eggs

Dying coral was the initial impetus for Drs. Christopher Taggart and Barry Ruddick’s research. To find out whether it could be “reestablished” was contingent first upon understanding how far coral eggs and larvae could be dispersed.

They developed the technique whereby tiny particles that mimic coral eggs and larvae were set free in the ocean. Magnetic collectors were placed within a 100-kilometre radius to attract the floating particles, made up of silica-glass and magnetite. “It is a remarkably simple, inexpensive solution to a very important problem,” says Ruddick.

The scientists simply count the number of particles caught to determine dispersion patterns. Their method has proven effective even in rough ocean conditions. “We tested it off the Florida coast, in the midst of hurricane season,” Ruddick explains. “The collectors performed as expected and didn’t suffer from the bad weather. It’s the simplicity of the technique that makes it so robust.”

Their findings showed that coral eggs and larvae can travel fair distances – at least 10 kilometres – which holds great promise for rebuilding the coral population. “Coral is particularly interesting because it is both an animal and a plant. It’s made up of two
different organisms that need each other to live,” explains Taggart. “When the ocean temperature rises, it can bleach the coral, meaning the plant part is expelled from the animal part. Now that we have shown that the coral eggs can disperse, it will be up to the coral reef ecologists to determine if the larvae can effectively recolonize a new population.”

While this will be instrumental in answering the coral “connectivity” question, the application is broad. It can help figure out the ‘how far’ questions about the potential impact of invasive species, or where the residual heavy metals from oil drilling end up.

“It’s a pragmatic method with many applications,” says Ruddick. “As long as we can shape the particle to mimic what is being studied, we can pretty much study the dispersion ability of anything in water.”

Reproduced from
OutFront Magazine: Research that Matters
Fall/Winter 2009/10 - vol. 4 no. 1