Tropical cyclones could have a significant role in the transfer of atmospheric carbon dioxide to long-term deposits in the deep ocean, suggests research online this week in Nature Geoscience. The global importance of this carbon sequestration remains to be assessed, but this link in the carbon cycle will be highly sensitive to any future changes in the frequency or intensity of tropical cyclones.
Robert Hilton and colleagues analysed the sediment composition of Taiwan’s LiWu river during periods of flooding induced by tropical cyclones, seeking to quantify the proportion of young organic carbon in the river ? that is, carbon recently taken up from the atmosphere. By looking at decades of river erosion, they estimate that 80?90% of this carbon is transported during cyclone-induced floods.
The findings suggest that both the frequency and intensity of typhoons can strongly affect the seaward transport of terrestrial young organic carbon. Such dense, sediment-laden floods are often injected directly into the deep ocean, potentially providing a mechanism for long-term carbon burial.