WHEN SPANISH MOSS EATS THE AIR IT MAKES A RECORD OF WHATS IN IT
By Amy Zukeran
Ordinarily, it's a silhouette in a horror movie stringy mass-es of Spanish moss dripping off swamp-swollen tree bran-ches. But an FSU geologist has begun research that puts the moss in the spotlight.
Professor Roy Odom and his researchers are looking at the moss's habit of collecting airborne metals like lead and mercury as a way of measuring the metals' presence in the environment.
Preliminary research suggests that air currents carry those metal particles across oceans, far from their sources.
If that is true, Odom's research could open the door to further global cooperation on air pollution issues.
The moss, an air plant, converts the sun's energy into food as its net-like tendrils absorb nutrients carried through the air. Though the moss apparently poses no health risks to humans, its feeding habits may help scientists determine where toxic metals originate and how they get into the environment.
"Like all other air plants, Spanish moss takes in everything," Odom explains. "It seems to be pretty good at absorbing heavy metals like lead and mercury. The plants suck these metals out of the air, and they become concentrated and saturated in the plants."'
Initial research conducted in the '70s revealed the usefulness of the plant in ferreting out possible sources of those metals, says Odom. Lead levels in Spanish moss growing by roadsides were substantially higher than in other locations. The source of the lead gasoline.
Using rainwater catchments and Spanish moss to get a reading of what is now in the air we breathe may make it possible to track sources of emissions and pollutants.
Certain types of elements decay to lead, and though "lead is lead," distinct differences separate the lead particles, depending on the source. The principle is similar to using fingerprints to separate the innocent from the guilty.
"Within a region, plants like these can be used for a broad-scale trend indicator," says Tom Atkeson, Florida Department of Environmental Protection's mercury coordinator. "It's an inexpensive and readily available plant. Cleverly applied, the plant can be very useful."
Odom's research, though years from conclusive, suggests a wind-borne, global spread of toxic metals. If that proves true, the research could change the way domestic and international emission policies are shaped.
"If Roy is right, and these heavy metals are coming from Africa or across the ocean, then there's very little use for local (clean air) regulations," said Vincent Salters, National High Magnetic Field Laboratory scholar and researcher. "We will have to address the problem from a global perspective."
Odom says heavy metals are severely invading lakes and estuaries.
"When that happens, the heavy metals get into the plants, which are then eaten by small animals that are then eaten by small fish," he said. "And as we saw with mercury, the metals become more concentrated up the food chain until the big fish aren't safe to eat."
More than 80 percent of commercially significant fish species rely on estuaries to provide shelter and food in some part of the life cycle.
If those toxic metals are indeed deposited primarily through the air, ocean-dependent countries may have pressing issues. And the ubiquitous but mostly ignored Spanish moss may be at the center of the debate.
"Nature provided us with a lot of tools to figure out what is going on around us," mused Salters. "It's our job to find these tools that nature gives us."