Quantifying the impact of anthropogenic nitrogen deposition on oceanic nitrous oxide

Anthropogenically induced increases in nitrogen deposition to the ocean can stimulate marine productivity and oceanic emission of nitrous oxide. We present the first global ocean model 12 assessment of the impact on marine N2O of increases in nitrogen deposition from the pre-industrial era to the present. We find significant regional increases in marine N2O production downwind of continental outflow, in coastal and inland seas (15-30%), and nitrogen limited regions of the North Atlantic and North Pacific (5-20%). The largest changes occur in the northern Indian Ocean (up to 16 50%) resulting from a combination of high deposition fluxes and enhanced N2O production 1pathways in local hypoxic zones. Oceanic regions relatively unaffected by anthropogenic nitrogen 18 deposition indicate much smaller changes (< 2%). The estimated change in oceanic N2O source on a global scale is modest (0.08 – 0.34 Tg N yr-1, ~3-4% of the total ocean source), and consistent 20 with the estimated impact on global export production (~4%).

SUNTHARALINGAM Parvadha;  BUITENHUIS Erik;  LE QUERE Corinne;  DENTENER Franciscus;  NEVISON Cynthia;  BUTLER James;  BANGE Hermann;  FORSTER Grant; 

2012-07-06

AMER GEOPHYSICAL UNION

JRC66386

0094-8276,   

http://www.agu.org/pubs/crossref/2012/2011GL050778.shtml,    https://publications.jrc.ec.europa.eu/repository/handle/JRC66386,   

10.1029/2011GL050778,