Study to Examine Vibrio Growth in Gulf of Mexico and Link to Saharan Dust

Vibrio, a bacteria that can thrive in the warm waters of the Atlantic Ocean, Gulf of Mexico, and the Caribbean, may be multiplying more quickly because of dust plumes from the Saharan/Sahel desert area in Africa that are being carried across the Atlantic and eventually deposited in ocean waters.

Current climate models predict that the Saharan/Sahel desert will grow hotter over the next 100 years, setting the stage for more dust to be released into the atmosphere. Researchers suspect that there may be more Vibrio outbreaks in the Gulf/Caribbean region in the near future if the dust is stimulatory to Vibrio, says researcher Michael Wetz, PhD, assistant professor of marine biology at Texas A&M University-Corpus Christi.

Vibrio are a diverse group of bacteria, including one species responsible for cholera outbreaks. Other species can cause flesh-eating wounds or severe gastrointestinal illness if harbored in shellfish that are consumed by humans, Dr. Wetz says. People most at risk for foodborne infection caused by Vibrio are those with liver disease, hemochromatosis, diabetes, several types of cancer, stomach disorders, and any illness or medical treatment that weakens the immune system.

Dr. Wetz has received a $220,758 grant from the National Science Foundation to evaluate how marine bacteria are responding to the long-term effects of the dust in the Florida Keys. His collaborators on the project include Erin Lipp, PhD, at the University of Georgia and the primary investigator on the project. Their work should provide some insight about how global climate changes are impacting marine bacteria that can affect seafood and the food supply.

“Dust deposition is a natural process that happens every summer, so the dust is already interacting with microbes, including Vibrio, in the Gulf,” Dr. Wetz explains. “What we don’t fully understand, and hope to determine from this study, is how the dust affects Vibrio growth.”

Early experiments by Dr. Lipp found that small-scale addition of dust to natural marine communities seems to trigger Vibrio growth. The researchers think that the iron contained in Saharan dust may be important for the growth of the bacteria. The dust may also be causing growth in microbes that cause coral disease in the Caribbean and growth of the red tide organism in the Gulf.

Other collaborators on the project include Bill Landing, PhD, at Florida State University; Liz Otteson, PhD, at the University of Georgia; Dale Griffin, PhD, at the U.S. Geological Survey; and Blair Sterba-Boatwright, PhD, at Texas A&M-Corpus Christi.


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