title: Saharan dust nutrients promote Vibrio bloom formation in marine surface waters.
abstract: Vibrio is a ubiquitous genus of marine bacteria, typically comprising a small fraction of the total microbial community in surface waters, but capable of becoming a dominant taxon in response to poorly characterized factors. Iron (Fe), often restricted by limited bioavailability and low external supply, is an essential micronutrient that can limit Vibrio growth. Vibrio species have robust metabolic capabilities and an array of Fe-acquisition mechanisms, and are able to respond rapidly to nutrient influx, yet Vibrio response to environmental pulses of Fe remains uncharacterized. Here we examined the population growth of Vibrio after natural and simulated pulses of atmospherically transported Saharan dust, an important and episodic source of Fe to tropical marine waters. As a model for opportunistic bacterial heterotrophs, we demonstrated that Vibrio proliferate in response to a broad range of dust-Fe additions at rapid timescales. Within 24 h of exposure, strains of Vibrio cholerae and Vibrio alginolyticus were able to directly use Saharan dust-Fe to support rapid growth. These findings were also confirmed with in situ field studies; arrival of Saharan dust in the Caribbean and subtropical Atlantic coincided with high levels of dissolved Fe, followed by up to a 30-fold increase of culturable Vibrio over background levels within 24 h. The relative abundance of Vibrio increased from ∼1 to ∼20% of the total microbial community. This study, to our knowledge, is the first to describe Vibrio response to Saharan dust nutrients, having implications at the intersection of marine ecology, Fe biogeochemistry, and both human and environmental health.
authors.affiliation: Department of Environmental Health Science, University of Georgia, Athens, GA 30602; Odum School of Ecology, University of Georgia, Athens, GA 30602;
authors.forename: Jason R
authors.initials: JR
authors.lastname: Westrich
authors.affiliation: Department of Earth, Ocean, and Atmospheric Science, Florida State University, Tallahassee, FL 32306;
authors.forename: Alina M
authors.initials: AM
authors.lastname: Ebling
authors.affiliation: Department of Earth, Ocean, and Atmospheric Science, Florida State University, Tallahassee, FL 32306;
authors.forename: William M
authors.initials: WM
authors.lastname: Landing
authors.affiliation: Department of Environmental Health Science, University of Georgia, Athens, GA 30602; Odum School of Ecology, University of Georgia, Athens, GA 30602;
authors.forename: Jessica L
authors.initials: JL
authors.lastname: Joyner
authors.affiliation: Department of Environmental Health Science, University of Georgia, Athens, GA 30602; Odum School of Ecology, University of Georgia, Athens, GA 30602;
authors.forename: Keri M
authors.initials: KM
authors.lastname: Kemp
authors.affiliation: Coastal and Marine Science Center, US Geological Survey, St. Petersburg, FL 33701.
authors.forename: Dale W
authors.initials: DW
authors.lastname: Griffin
authors.affiliation: Department of Environmental Health Science, University of Georgia, Athens, GA 30602; elipp@uga.edu.
authors.forename: Erin K
authors.identifier: 0000-0002-8066-0636
authors.initials: EK
authors.lastname: Lipp
mesh_terms: D000352:Africa, Northern; D059001:Aquatic Organisms / Q000254:growth & development*; D004391:Dust; D006801:Humans; D012623:Seawater / Q000382:microbiology*; D014733:Vibrio / Q000254:growth & development*; D014871:Water Microbiology
chemical_list: D004391:Dust
keywords: Saharan dust; Vibrio; iron; marine biogeochemistry; microbial ecology