Weatherwatch: how hurricanes impact the deep ocean

Hurricanes lead to flooding and toppled trees on land, but their impact on the oceans is less well understood. The University of Chicago’s Oceanic Flux Program (OFP) aims to fill the gaps. The OFP is based in the Sargasso Sea, on a floating platform moored 47 miles (75km) off Bermuda.

Sediment traps at different depths collect fragments of microplankton shells and other detritus as it drifts down towards the deep ocean. A study of OFP data has revealed how hurricanes affect the process of sediment deposition, creating underwater waves that sweep material from the reefs in shallow water into the deep. The research found that Hurricane Fabian delivered a whole years’ worth of material in just two weeks in 2003.



However, the study showed that different hurricanes have had different effects. One of the investigators, Dr Rut Pedrosa Pamies, said: “It depends a lot on the ocean depth of the area, the upper-ocean conditions and the hurricane characteristics.” The laying down of sediment, rich in carbonate materials from shells and coral skeletons, has far-reaching effects.

When laid down on the deep ocean floor, carbonates sequester carbon for thousands of years, and the material locked up helps offset rising ocean acidification. Major storms clearly play a significant role in the deposition process, a role which is only now starting to be understood..