The depth-distribution of nitrogen fixation by Trichodesmium spp. colonies in the tropical–subtropical North Atlantic

Thumbnail Image
Olson, Elise M. B.
McGillicuddy, Dennis J.
Dyhrman, Sonya T.
Waterbury, John B.
Davis, Cabell S.
Solow, Andrew R.
Alternative Title
Date Created
Related Materials
Replaced By
Nitrogen fixation
Trichodesmium spp.
North Atlantic
Video Plankton Recorder
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 higher than expected Trichodesmium colony abundances at depth, leading to the hypothesis that deep nitrogen fixation in the North Atlantic may have been previously underestimated. Here, Trichodesmium colony abundances and modeled nitrogen fixation from VPR transects completed on two cruises in the tropical and subtropical North Atlantic in fall 2010 and spring 2011 were used to evaluate that hypothesis. A bio-optical model was developed based on carbon-normalized nitrogen fixation rates measured on those cruises. Estimates of colony abundance and nitrogen fixation were similar in magnitude and vertical and geographical distribution to conventional estimates in a recently compiled climatology. Thus, in the mean, VPR-based estimates of volume-specific nitrogen fixation rates at depth in the tropical North Atlantic were not inconsistent with estimates derived from conventional sampling methods. Based on this analysis, if Trichodesmium nitrogen fixation by colonies is underestimated, it is unlikely that it is due to underestimation of deep abundances by conventional sampling methods.
© The Author(s), 2015. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Deep Sea Research Part I: Oceanographic Research Papers 104 (2015): 72-91, doi:10.1016/j.dsr.2015.06.012.
Embargo Date
Deep Sea Research Part I: Oceanographic Research Papers 104 (2015): 72-91
Cruise ID
Cruise DOI
Vessel Name
Except where otherwise noted, this item's license is described as Attribution-NonCommercial-NoDerivatives 4.0 International