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Distribution and rates of nitrogen fixation in the western tropical South Pacific Ocean constrained by nitrogen isotope budgets.
- Source :
- Biogeosciences; 2018, Vol. 15 Issue 9, p2619-2628, 10p, 1 Chart, 1 Map
- Publication Year :
- 2018
-
Abstract
- Constraining the rates and spatial distribution of dinitrogen (N<subscript>2</subscript>/ fixation fluxes to the ocean informs our understanding of the environmental sensitivities of N<subscript>2</subscript> fixation as well as the timescale over which the fluxes of nitrogen (N) to and from the ocean may respond to each other. Here we quantify rates of N<subscript>2</subscript> fixation as well as its contribution to export production along a zonal transect in the western tropical South Pacific (WTSP) Ocean using N isotope ("δ<superscript>15</superscript>N") budgets. Comparing measurements of water column nitrateCnitrite δ<superscript>15</superscript>N with the δ<superscript>15</superscript>N of sinking particulate N at a western, central, and eastern station, these δ<superscript>15</superscript>N budgets indicate high, modest, and low rates of N<subscript>2</subscript> fixation at the respective stations. The results also imply that N<subscript>2</subscript> fixation supports exceptionally high, i.e. ⩾50 %, of export production at the western and central stations, which are also proximal to the largest iron sources. These geochemically based rates of N<subscript>2</subscript> fixation are equal to or greater than those previously reported in the tropical North Atlantic, indicating that the WTSP Ocean has the capacity to support globally significant rates of N<subscript>2</subscript> fixation, which may compensate for N removal in the oxygen-deficient zones of the eastern tropical Pacific. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 17264170
- Volume :
- 15
- Issue :
- 9
- Database :
- Complementary Index
- Journal :
- Biogeosciences
- Publication Type :
- Academic Journal
- Accession number :
- 129715042
- Full Text :
- https://doi.org/10.5194/bg-15-2619-2018