Dusty Beginnings

UM Rosenstiel scientists studied how fertilization of region could trigger carbonate formation. July 25, 2014 MIAMI - A new study suggests that Saharan dust played a major role in the formation of the Bahamas islands. Researchers from the University of Miami (UM) Rosenstiel School of Marine and Atmospheric Science showed that iron-rich Saharan dust provides the nutrients necessary for specialized bacteria to produce the island chain's carbonate-based foundation. UM Rosenstiel School Lewis G. Weeks Professor Peter Swart and colleagues analyzed the concentrations of two trace elements characteristic of atmospheric dust - iron and manganese - in 270 seafloor samples collected along the Great Bahama Bank over a three-year period. The team found that the highest concentrations of these trace elements occurred to the west of Andros Island, an area which has the largest concentration of whitings, white sediment-laden bodies of water produced by photosynthetic cyanobacteria. "Cyanobacteria need 10 times more iron than other photosynthesizers because they fix atmospheric nitrogen," said Swart, lead author of the study. "This process draws down the carbon dioxide and induces the precipitation of calcium carbonate, thus causing the whiting.