Nitrogen is a critical nutrient for all organisms. Increasing quantities of fixed nitrogen, currently ~54 Tg yr-1, are entering the open ocean via the atmosphere as a result of human activities. This geographically and temporally variable input accounts for ~32% of the external (non-recycled) nitrogen supply to the ocean globally and can account for up to ~3% of the annual new marine biological production, or ~0.3 Pg C yr-1, which is comparable in magnitude to productivity associated with marine biological N2-fixation. Roughly 10% of the present anthropogenic carbon uptake by the ocean could be attributed to anthropogenic nitrogen fertilization. Anthropogenic atmospheric nitrogen input also results in the production of ~1.7 Tg yr-1 of the greenhouse gas nitrous oxide, approximately one third of its total estimated emission from the ocean and ~23% of the emission of this gas from all human activities. The decrease in radiative forcing from increased CO2 uptake resulting from anthropogenic nitrogen deposition outweighs the increase in radiative forcing from increased N2O emissions by up to 40%. These effects are expected to show a substantial increase in the future.

DUCE Bob;  LAROCHE J.;  ALTIERI K.;  ARRIGO K. R.;  BAKER A. R.;  CAPONE D.G.;  CORNELL S.;  DENTENER Franciscus;  GALLOWAY J.N.;  GANESHRAM R. S.;  GEIDER R. J.;  JICKELLS T.;  KUYPERS M. M.;  LANGLOIS R.;  LISS P. S.;  LIU S. M.;  MIDDELBURG J. J.;  MOORE C. M.;  NICKOVIC S.;  OSCHLIES A.;  PEDERSEN T.;  PROSPERO J.;  SCHLITZER R.;  SEITZINGER S.P.;  SORENSEN L . L.;  UEMATSU M.;  ULLOA O.;  VOSS M.;  WARD B.;  ZAMORA L. M.; 

2008-05-20

AMER ASSOC ADVANCEMENT SCIENCE

JRC42419

0036-8075,   

https://publications.jrc.ec.europa.eu/repository/handle/JRC42419,   

10.1126/science.1150369,