Impacts of increasing anthropogenic soluble iron and nitrogen deposition on ocean biogeochemistry
Moore, J. Keith
Mahowald, Natalie M.
Doney, Scott C.
Zender, Charles S.
MetadataShow full item record
We present results from transient sensitivity studies with the Biogeochemical Elemental Cycling (BEC) ocean model to increasing anthropogenic atmospheric inorganic nitrogen (N) and soluble iron (Fe) deposition over the industrial era. Elevated N deposition results from fossil fuel combustion and agriculture, and elevated soluble Fe deposition results from increased atmospheric processing in the presence of anthropogenic pollutants and soluble Fe from combustion sources. Simulations with increasing Fe and increasing Fe and N inputs raised simulated marine nitrogen fixation, with the majority of the increase in the subtropical North and South Pacific, and raised primary production and export in the high-nutrient low-chlorophyll (HNLC) regions. Increasing N inputs alone elevated small phytoplankton and diatom production, resulting in increased phosphorus (P) and Fe limitation for diazotrophs, hence reducing nitrogen fixation (∼6%). Globally, the simulated primary production, sinking particulate organic carbon (POC) export. and atmospheric CO2 uptake were highest under combined increase in Fe and N inputs compared to preindustrial control. Our results suggest that increasing combustion iron sources and aerosol Fe solubility along with atmospheric anthropogenic nitrogen deposition are perturbing marine biogeochemical cycling and could partially explain the observed trend toward increased P limitation at station ALOHA in the subtropical North Pacific. Excess inorganic nitrogen ([NO3 −] + [NH4 +] − 16[PO4 3−]) distributions may offer useful insights for understanding changing ocean circulation and biogeochemistry.
Author Posting. © American Geophysical Union, 2009. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Global Biogeochemical Cycles 23 (2009): GB3016, doi:10.1029/2008GB003440.
Showing items related by title, author, creator and subject.
Sholkovitz, Edward R.; Sedwick, Peter N.; Church, Thomas M.; Baker, Alexander R.; Powell, Claire F. (2012-03-26)Aerosol deposition provides a major input of the essential micronutrient iron to the open ocean. A critical parameter with respect to biological availability is the proportion of aerosol iron that enters the oceanic ...
Variability in the carbon isotopic composition of foliage carbon pools (soluble carbohydrates, waxes) and respiration fluxes in southeastern U.S. pine forests Mortazavi, Behzad; Conte, Maureen H.; Chanton, Jeffrey P.; Weber, John C.; Martin, Timothy A.; Cropper, Wendell P. (American Geophysical Union, 2012-04-19)We measured the δ13C of assimilated carbon (foliage organic matter (δCOM), soluble carbohydrates (δCSC), and waxes (δCW)) and respiratory carbon (foliage (δCFR), soil (δCSR) and ecosystem 13CO2 (δCER)) for two years at ...
Cloud condensation nucleus activity comparison of dry- and wet-generated mineral dust aerosol : the significance of soluble material Garimella, S.; Huang, Y.-W.; Seewald, Jeffrey S.; Cziczo, D. J. (Copernicus Publications on behalf of the European Geosciences Union, 2014-06-18)This study examines the interaction of clay mineral particles and water vapor for determining the conditions required for cloud droplet formation. Droplet formation conditions are investigated for two common clay minerals, ...