After the Fury, Hurricanes can Leave a Lasting Mark on the Deep Ocean
WOODS HOLE, Mass. – The impact of hurricanes when they travel over land, or when they affect ships or oil-drilling platforms, are quite well understood. But these huge cyclones also stir up the ocean itself, with consequences that are relatively unknown and hard to study.
But a unique, subsurface experimental platform moored to the floor of the Sargasso Sea, about 47 miles southeast of Bermuda, is changing that. With collection points at increasing depths along the mooring line, the traps constantly collect the sinking particles of sediment, microplankton shells, detritus, and pollutants that drift down into the deep ocean, sampling every two weeks to provide a -long record of changes in the environment.
And now, that moored observatory, run by the Oceanic Flux Program (OFP) at the Marine Biological Laboratory ( 黨ǿƵ), has provided detailed data that for the first time demonstrates how much of an impact hurricanes can have on this deep environment.
A team led by 黨ǿƵ Assistant Research Investigator Rut Pedrosa-Pamies studied the sediments that Hurricanes Fabian (2003) and Igor (2010) transported from the Bermuda carbonate platform -- a shallow-water reef refuge for marine life – and deposited to the deep ocean. They found significant effects that lasted for weeks. They published their data last week in
Hurricane Fabian, it turns out, delivered as much sediment to the deep ocean in just two weeks as would normally take a full year to accumulate. These sediments -- carbonate-rich material that forms in the thriving ecosystem on reef platforms -- have major effects on the ocean environment. If they get buried in deep sediments, they can sequester carbon for millennia or more. They can also provide a buffering effect to help offset ocean acidification, a consequence of rising atmospheric CO2 concentrations.
“This is the first time that a study has demonstrated, in near real time, this hurricane-induced transport from a shallow carbonate platform to the deep ocean,” Pedrosa-Pamies says. “And it’s not just carbonate; [a hurricane] also transports a lot of other materials like phosphorus, lithogenic minerals, and also pollutants, such as lead.”
Fabian and Igor in the Deep Sea