Windblown nutrients may fertilize island-building bacteria
The Bahamas owes its origins to windswept dust from Africa’s Sahara Desert, scientists propose June 30 in Geology.
The dust nourishes microbes that produce calcium carbonate, the core building block of the Bahama Islands, the researchers say. Over the last 100 million years this carbonate has assembled into the Great Bahama Bank, a 4.5-kilometer-thick platform. This underwater shelf the size of Iceland forms the base of much of the Bahama Archipelago.
“Without this dust, the Bahamas might never be there,” says geochemist Peter Swart of the University of Miami in Florida. “We’d just have a big open ocean and maybe a little underwater bump on sonar.”
The Great Bahama Bank is still growing outward toward Miami as fresh carbonate sediment collects on its borders. Other carbonate platforms, such as the Great Barrier Reef, form from the