Preliminary estimate of contribution of Arctic nitrogen fixation to the global nitrogen budget

Dinitrogen (N-2) fixation is the source of all biologically available nitrogen on earth, and its presence or absence impacts net primary production and global biogeochemical cycles. Here, we report rates of 3.5-17.2 nmol N L-1 d(-1) in the ice-free coastal Alaskan Arctic to show that N-2 fixation in...

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Bibliographic Details
Published in:Limnology and Oceanography Letters
Main Authors: Sipler, Rachel E., Gong, Donglai, Baer, SE, Sanderson, MP, Roberts, QN, Mulholland, M, Bronk, DA
Format: Text
Language:unknown
Published: W&M ScholarWorks 2017
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Online Access:https://scholarworks.wm.edu/vimsarticles/1436
https://scholarworks.wm.edu/context/vimsarticles/article/2433/viewcontent/Sipler_et_al_2017_Limnology_and_Oceanography_Letters.pdf
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Summary:Dinitrogen (N-2) fixation is the source of all biologically available nitrogen on earth, and its presence or absence impacts net primary production and global biogeochemical cycles. Here, we report rates of 3.5-17.2 nmol N L-1 d(-1) in the ice-free coastal Alaskan Arctic to show that N-2 fixation in the Arctic Ocean may be an important source of nitrogen to a seasonally nitrogen-limited system. If widespread in surface waters over ice-free shelves throughout the Arctic, N-2 fixation could contribute up to 3.5 Tg N yr(-1) to the Arctic nitrogen budget. At these rates, N-2 fixation occurring in ice-free summer waters would offset up to 27.1% of the Arctic denitrification deficit and contribute an additional 2.7% to N-2 fixation globally, making it an important consideration in the current debate of whether nitrogen in the global ocean is in steady state. Additional investigations of high-latitude marine diazotrophic physiology are required to refine these N-2 fixation estimates.