By: Bill Wellock | Published: | 1:25 pm

More dust from the Sahara Desert is forecast to come to the United States this week. The massive dust plume known as the Saharan Air Layer has a myriad of effects on air quality, fertilizing ecosystems and more.

Florida State University has experts available to comment on some of the surprising features related to the meteorological phenomenon.

Angela Knapp, associate professor of chemical oceanography

Knapp studies the nutrient sources that fuel carbon fixation in the ocean, including the processes that affect the amount of nitrogen in the ocean. Regarding the Saharan Air Layer, this work involves understanding the potential biological and chemical consequences of that dust deposition in the ocean. Her lab uses geochemical tools to track the unique chemical signatures Trichodesmium spp. leaves in the ocean to quantify the sources of nutrients fueling these and other phytoplankton growing in the Gulf of Mexico and around the world.

“The importance of the Saharan dust for fueling phytoplankton that bloom on the West Florida Shelf is an open question. Prior research has suggested that Saharan dust triggers blooms of a cyanobacterium, Trichodesmium spp., on the West Florida Shelf that can fertilize other phytoplankton, including Karenia brevis, which causes the so-called harmful Florida red tide. 

“Historically, K. brevis blooms typically follow Trichodesmium blooms on the West Florida Shelf. However, before the Saharan dust arrived this year there was already a massive Trichodesmium spp. bloom on the West Florida Shelf. It will be interesting to see whether Trichodesmium spp. increase in response to the Saharan dust deposition and whether a bloom of the harmful algae K. brevis follows the Trichodesmium bloom.”

William Landing, professor emeritus of oceanography

Landing is an emeritus professor in the Department of Earth, Ocean and Atmospheric Science. His research interests include the biogeochemistry of trace elements in marine and fresh waters. He has served as the chair of the American Chemical Society geochemistry division and as a member of the US GEOTRACES Steering Committee.

“Microscopic algae in the ocean are incredibly important. They produce about half the oxygen we breathe, remove billions of tons of carbon dioxide from the atmosphere each year and serve as a base of marine food webs. But they need iron, an essential trace element, to function. The main source for iron in the open ocean is from dust deposition, which is something that the Saharan Air Layer brings to the Atlantic Ocean, the Caribbean and the Gulf of Mexico.” 

Peter Morton, visiting assistant research scientist in geochemistry at the National High Magnetic Field Laboratory

Morton studies the molecular composition of the Saharan Air Layer and how that varies depending on its origin and what happens along its global journey.

The Saharan dust plume is a regular seasonal occurrence and provides essential nutrients like iron and phosphorus to marine plants, algae and bacteria in the waters around Florida. Our research at the National High Magnetic Field Laboratory explores how much of the dust falls to the ocean and how much of the precious nutrients in dust are accessible by the marine microorganisms.”

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