By Susan Milius
Choppy waters and even mellow surf can knock drifting coral embryos to bits. But it takes more than shattering to kill these resilient young animals. The fragments turn out to have the power to keep on growing as clones.
Many corals start life adrift in open water, forming when eggs and sperm released by their settled parents float to the sea surface and mingle. The new embryos often face at least somewhat rough water on about half of the spawning nights in the central Great Barrier Reef. Lab tests mimicking these conditions split apart 45 percent of coral embryos just starting to divide, says Andrew Negri with the Australian Institute of Marine Science in Townsville. Yet checking on these remnants showed plenty of survivors that remained small but matured normally, Negri and Institute colleague Andrew Heyward of Perth report in the March 2 Science.
“A pretty cool observation,” says coral biologist Nancy Knowlton of the Smithsonian Institution’s National Museum of Natural History in Washington, D.C. “What makes it neat is not that the developing embryos can clone per se, but they are likely to do it under natural circumstances.”