Sea gauge will plot
drifting coral larvae
Like tracking grains of sand, scientists are using high-tech devices to follow millions of microscopic coral larvae off the coast of Maui. And they'll be doing it in the dark.
By mapping the nocturnal journeys of some of the tiniest of sea animals, researchers from the U.S. Geological Survey, the Universities of Hawaii and Washington, the state Aquatic Resources Division and the Maui Ocean Center hope to learn more about why some reefs around the island do well and others deteriorate.
The unique experiment involves a disk that floats on the top of the water and fins below the surface with a satellite antennae to transmit data. They will collect information that is expected to show how waves, currents and the properties of sea water affect the larvae's movement.
The study was timed to start during the new moon -- last night -- when coral spawning ensues, said USGS oceanographer Curt Storlazzi.
A key element in the world's oceans, corals are sea animals that bond together in colonies, secreting hard outer skeletons that form coral reefs.
Storlazzi said that one of the principal coral for building Hawaii's reefs, known as "rice coral," follows a fascinating annual ritual, releasing eggs and sperm at about 9 p.m. local time each evening for four nights starting one day after the new moons in May through August.
Packets of eggs rise to the surface, according to scientists, and float along with the currents until the fertilized eggs, or larvae, sink and start to grow on ocean rock or other coral.
The question scientists are trying to answer is where the currents are carrying the larvae, Storlazzi said.
According to Eric Brown, a University of Hawaii researcher, some coastal areas may lack viable reefs "simply because the larvae are unable to settle."
Underwater tripods, operating much like lunar landers, will be placed on the ocean floor to measure water temperature, clarity, wave action and currents. Above, the umbrellalike satellite-tracked devices will drift on the surface at night to float along with the larvae.
Storlazzi said currents off Maui are complex and that it will take days to get a clear picture of the larvae's wanderings.