A new weapon to monitor red tide

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A remote-controlled undersea glider will patrol Florida’s coast this summer collecting environmental data

A remote-controlled undersea glider will patrol Florida’s coast this summer collecting environmental data

Mote Marine Laboratory in Sarasota, Fla., will be sending remote-controlled undersea gliders into the Gulf of Mexico this summer in hot pursuit of the algae that cause blooms of toxic red tide.

Slocum Gliders, torpedo-like devices with wings, will be patrolling Gulf waters for 15 to 20 days at a stretch looking for the Karenia brevis algae responsible for the blooms that cause massive fish kills and trigger respiratory ailments landside when the algae are wind-borne.

The 7-foot-long, bright yellow gliders will operate 10 to 30 miles offshore between AnnaMariaIsland in the north and Boca Grande to the south, says Mote senior scientist Gary Kirkpatrick.

“It’s really a very clever device,” says Kirkpatrick, who helped develop the BreveBuster, a red tide detector inside the glider that collects water samples and analyzes them for the toxic algae.

He says Mote has three of the gliders, which will relieve or work with each other this summer, as conditions demand. Typically a battery-powered glider will make close-in sweep south, then a sweep north and farther out over a period of 15 to 20 days.

It will patrol at different depths in a kind of a saw tooth pattern, first taking in water in its nose and shifting its battery pack forward so that it dives down. Then when the glider draws close to the bottom, an acoustic altimeter will trigger the release of the water ballast and a shift of the battery pack back so the nose points up and the glider begins a slow ascent.

Every two or three hours, the glider will surface, a balloon will inflate at its tail, and a GPS and an Iridium satellite phone antenna will point into the air so the device can take a GPS fix and call home to Mote scientists. It will use the Iridium phone to send data it has collected about each water sample — the salinity, temperature, depth where it was collected and whether Karenia was detected — and to ask scientists whether they want it to continue on its course or re-

direct it somewhere else.

Fitzpatrick says NOAA satellite photos of chlorophyll in the water will help scientists decide where to send the gliders to seek out the dangerous algae. The gliders aren’t the only data collection stations. Fitzpatrick says Mote has placed BreveBusters on buoys, on pleasure boats and commercial vessels, on piers and at other locations to collect and analyze samples, and send data back to Mote.

The information from the gliders can identify blooms as they develop, and help enable scientists to predict their movement and issue alerts. Using ocean models, scientists can predict the movement of blooms 24 hours out, Fitzpatrick says. Their aim is to be able to issue three-day forecasts so fishermen, aquaculturalists and coastal residents can prepare for the blooms. He says red tide forecasts are even more difficult to make than weather forecasts because models must factor in not only physical forces, but biological and chemical variables.

Red tides can leave acres of beach covered with dead fish, driving off tourists and creating a health threat to residents. The Florida Fish and Wildlife Institute posts red tide alerts and updates based on Mote’s and other information at its Web site, www.floridamarine.org, and in recorded messages at (866) 300-9399 (toll-free in Florida) and (727) 552-2448 (outside Florida).