National Institute Of Oceanography( NIO ) - Enhancement of oceanic nitrous oxide emissions by storms

Enhancement of oceanic nitrous oxide emissions by storms

Weather disturbances such as storms can, nevertheless, deepen the mixed layer considerably, thereby entraining N₂O from the subsurface maximum to the surface layer, where it easily escapes to the atmosphere. This simple scenario of enhanced N₂O emissions from the ocean caused by strong wind events (such as cyclones in the North Indian Ocean and hurricanes in the East Pacific Ocean) has never been demonstrated because scientific ship campaigns usually avoid storms. In a recent paper, NIO's scientists have provided the first evidence for this phenomenon. These authors could obtain data on vertical distribution of N₂O in the central Arabian Sea just before and after a cyclone crossed the region in December 1998, and found a significant enhancement of N₂O concentration in the surface layer along with a decrease in temperature and an enrichment of macronutrients (nitrate and phosphate), all testifying to intense vertical mixing caused by the cyclone. On the basis of their data they calculated that the N2O inventory in the upper 50 meters increased by about 2.3 Gg N₂O following the cyclone.

For more information read: Naik, H.; Naqvi, S.W.A.; Suresh, T.; Narvekar, P.V. Impact of tropical cyclone on biogeochemistry of the central Arabian Sea. Global Biogeochem. Cycles: 22(3); 2008; doi:10.1029/2007GB003028; 11 pp.

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