How widespread and important is N2 fixation in the North Atlantic Ocean?
The spatial extent of N2 fixation in the Atlantic Ocean is examined by determining the isotopic composition of N in suspended particulate organic nitrogen (δ15N PONsusp). The samples were collected from zonal and meridional transects of the Atlantic Ocean during a 3-year period. There is a consisten...
| Published in: | Global Biogeochemical Cycles |
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| Main Authors: | , , , , , , |
| Format: | Article in Journal/Newspaper |
| Language: | unknown |
| Published: |
2007
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| Subjects: | |
| Online Access: | http://nora.nerc.ac.uk/id/eprint/150276/ http://www.agu.org/journals/gb/gb0704/2006GB002886/ https://doi.org/10.1029/2006GB002886 |
| Summary: | The spatial extent of N2 fixation in the Atlantic Ocean is examined by determining the isotopic composition of N in suspended particulate organic nitrogen (δ15N PONsusp). The samples were collected from zonal and meridional transects of the Atlantic Ocean during a 3-year period. There is a consistent depleted δ15N PONsusp signal extending over the center of the northern subtropical gyre, which partly coincides with a region where the tracer N* increases westward following the gyre circulation. This nonconservative behavior of N* implies that N2 fixation is responsible for the depleted δ15N PONsusp. A mixing model suggests that N2 fixation over parts of the northern gyre provides up to 74% of the N utilized by phytoplankton. However, since the PONsusp represents only a small fraction of the total N pool, N2 fixation probably only plays a minor role in supplying new N to the euphotic zone in the surface waters of the northern subtropical gyre. |
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