Is African Dust Causing Red Tide?
Scientists also suspect a connection between African dust and red tide, harmful algal blooms that can result in fish kills and force costly beach closures. “The dust coming over from Africa contains a lot of iron,” says University of South Florida graduate student Jason Lenes, who is completing his doctorate in biological oceanography. When iron is deposited in the water, a certain percentage dissolves and sparks production of bluegreen algae. “What’s special about the blue-green algae,” Lenes explains, “is its ability to ‘fix’ nitrogen, converting it from an unusable form to a usable form – and it takes a lot of iron to do that.” While red tide is a naturally occurring phenomenon, it may be induced by manmade factors. “When you’re dealing with the west Florida shelf, there aren’t a lot of nutrients out there, so it’s hard for us to explain how we get the amount of red tide we do.” Lenes is modeling data from 1998 to 2001 to try to establish concurrence between African dust, rainfall a
