Atmospherically transported dust from the Sahara Desert, the largest desert in the world, is bringing iron and other nutrients to underwater plants in the Caribbean, but bacteria may be the first thing to prosper from that dust, according to a new research published in the Proceedings of the National Academy of Sciences.
Sahara, Libya. Image credit: Victor Korniyenko / CC BY-SA 3.0.
“The dust is causing the bacteria to bloom and also become more toxic to humans and marine organisms. This has been going on for a long time, but nobody understood it. It’s a natural phenomenon,” said co-author Prof. William Landing of Florida State University.
Prof. Landing and his colleagues from the University of Georgia, the U.S. Geological Survey and Florida State University used Vibrio — a well-characterized genus of marine bacteria, typically comprising a small fraction of the total microbial community in surface waters — as a model for the biological response.
“Vibrio includes pathogens that cause cholera, gastroenteritis and seawater-associated wound infections,” Prof. Landing said.
“Some are quite toxic. And they can infect and accumulate in shellfish.”
The scientists were particularly interested in how the bacteria Vibrio responded to the dust that had traveled thousands of miles.
They found that the bacteria were uniquely positioned to immediately process the dust when it entered the system.
It caused the bacteria to bloom and become more toxic. And with more bacteria, there were fewer nutrients available for other marine life.
“They’re kind of like a first responder to the Saharan dust,” said co-author Alina Ebling from Florida State University.
“All life needs iron, and Vibrio is getting to it first.”
On a broader scale, scientists are eager to better understand the entire biological process of how marine life responds to this dust as added iron could ‘fertilize’ ocean plankton and plants.
A more vigorous ocean plant system would be more capable of processing additional carbon dioxide, something that could be important with climate change.
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Jason R. Westrich et al. Saharan dust nutrients promote Vibrio bloom formation in marine surface waters. PNAS, published online May 9, 2016; doi: 10.1073/pnas.1518080113
