Do Trichodesmium spp. populations in the North Atlantic export most of the nitrogen they fix?
McGillicuddy, Dennis J.
MetadataShow full item record
A new observational synthesis of diazotrophic biomass and nitrogen fixation provides the opportunity for systematic quantitative evaluation of these aspects in biogeochemical models. One such model of the Atlantic Ocean is scrutinized, and the simulated biomass is found to be an order of magnitude too low. Initial attempts to increase biomass levels through decreasing grazing and other loss terms caused an unrealistic buildup of nitrate in the upper ocean. Two key changes to the model structure facilitated a closer match to the observed biomass and nitrogen fixation rates: addition of a pathway for export of diazotrophically fixed organic material and uptake of inorganic nitrogen by the diazotroph population. These changes, along with a few other revisions to existing model parameterizations, facilitate more accurate simulation of basin-scale distributions of diazotrophic biomass, as well as mesoscale variations contained therein. The resulting solutions suggest that the Trichodesmium spp. populations of the North Atlantic export the vast majority of the nitrogen they fix, a finding that awaits assessment through direct observation.
Author Posting. © American Geophysical Union, 2014. 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 28 (2014): 103-114, doi:10.1002/2013GB004652.
Suggested CitationGlobal Biogeochemical Cycles 28 (2014): 103-114
Showing items related by title, author, creator and subject.
The depth-distribution of nitrogen fixation by Trichodesmium spp. colonies in the tropical–subtropical North Atlantic Olson, Elise M. B.; McGillicuddy, Dennis J.; Dyhrman, Sonya T.; Waterbury, John B.; Davis, Cabell S.; Solow, Andrew R. (Elsevier, 2015-07-02)Nitrogen fixation is an important yet still incompletely constrained component of the marine nitrogen cycle, particularly in the subsurface. A Video Plankton Recorder (VPR) survey in the subtropical North Atlantic found ...
N2 fixation by subsurface populations of Trichodesmium : an important source of new nitrogen to the North Atlantic Ocean Heithoff, Abigail (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2011-02)Trichodesmium, a genus of diazotrophic cyanobacteria, is an important contributor to the marine nitrogen (N) and carbon (C) cycles. The extent to which Trichodesmium dinitrogen (N2) fixation contributes to the marine N ...
Nitrogen and carbon fixation rates from Trichodesmium colonies from RV/Atlantic cruise AT39-05, Feb-Mar 2018 Hutchins, David A.; Webb, Eric A (Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: email@example.com, 2020-05-04)Nitrogen and carbon fixation rates from Trichodesmium colonies from RV/Atlantic cruise AT39-05, Feb-Mar 2018. For a complete list of measurements, refer to the full dataset description in the supplemental file ...