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Dissolved Organic Nitrogen Production And Consumption In Eastern Tropical South Pacific Surface Waters

Title: Dissolved Organic Nitrogen Production And Consumption In Eastern Tropical South Pacific Surface Waters.
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Name(s): Knapp, A. N., author
Casciotti, K. L., author
Prokopenko, M. G., author
Type of Resource: text
Genre: Journal Article
Text
Journal Article
Date Issued: 2018-05-01
Physical Form: computer
online resource
Extent: 1 online resource
Language(s): English
Abstract/Description: Models of dissolved organic nitrogen (DON) production and consumption indicate that marine DON is produced in the euphotic zone, especially in upwelling environments, and is consumed as it transits into more oligotrophic regions where it may support export production. However, evaluation of such models is data limited, and in particular, few measurements of DON concentration and/or nitrogen isotopic composition (N-15) exist from the South Pacific. Here we present measurements of the concentration and N-15 of DON collected in the eastern tropical South Pacific during the austral summers of 2010 (El Nino) and 2011 (La Nina). The concentration and N-15 of DON from the eastern tropical South Pacific are broadly consistent with prior measurements elsewhere, that is, DON concentrations of 51M and DON N-15 of 51, but variations were associated with DON production and consumption. Specifically, surface ocean chlorophyll a concentrations were highly correlated with upper 50-m DON stocks (r=0.96), consistent with a photosynthetic source for DON. Additionally, upper 50-m DON stocks and their N-15 were significantly negatively correlated (r=-0.84, p=0.0006), indicating that DON was consumed in surface waters with an isotope effect of 5.51.2 parts per thousand. These results inform our understanding of the controls of DON distributions in the surface ocean and indicate that DON may support export production in nitrate-poor surface waters, which may decouple new from gross production.
Identifier: FSU_libsubv1_wos_000434413500003 (IID), 10.1029/2017GB005875 (DOI)
Keywords: fresh-water, South Pacific, nitrogen, sargasso sea, nitrogen isotopes, net community production, anthropogenic nitrogen, dissolved organic nitrogen, don, eastern tropical South Pacific, gross oxygen production, kinetic fractionation, o-18/o-16 ratios, peptide-bond hydrolysis, subtropical gyre, triple-isotope composition
Publication Note: The publisher’s version of record is available at https://doi.org/10.1029/2017GB005875
Persistent Link to This Record: http://purl.flvc.org/fsu/fd/FSU_libsubv1_wos_000434413500003
Owner Institution: FSU
Is Part Of: Global Biogeochemical Cycles.
0886-6236
Issue: iss. 5, vol. 32

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Knapp, A. N., Casciotti, K. L., & Prokopenko, M. G. (2018). Dissolved Organic Nitrogen Production And Consumption In Eastern Tropical South Pacific Surface Waters. Global Biogeochemical Cycles. Retrieved from http://purl.flvc.org/fsu/fd/FSU_libsubv1_wos_000434413500003