Dissolved Organic Nitrogen Production and Consumption in Eastern Tropical South Pacific Surface Waters

Dissolved Organic Nitrogen Production and Consumption in Eastern Tropical South Pacific Surface... 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 (“δ15N”) exist from the South Pacific. Here we present measurements of the concentration and δ15N of DON collected in the eastern tropical South Pacific during the austral summers of 2010 (El Niño) and 2011 (La Niña). The concentration and δ15N of DON from the eastern tropical South Pacific are broadly consistent with prior measurements elsewhere, that is, DON concentrations of 5 ± 1 μM and DON δ15N of 5 ± 1‰, 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 δ15N were significantly negatively correlated (r = −0.84, p = 0.0006), indicating that DON was consumed in surface waters with an isotope effect of 5.5 ± 1.2‰. 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. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Global Biogeochemical Cycles Wiley

Dissolved Organic Nitrogen Production and Consumption in Eastern Tropical South Pacific Surface Waters

Loading next page...
 
/lp/wiley/dissolved-organic-nitrogen-production-and-consumption-in-eastern-gDwvH0ckJ0
Publisher
Wiley
Copyright
©2018. American Geophysical Union. All Rights Reserved.
ISSN
0886-6236
eISSN
1944-9224
D.O.I.
10.1029/2017GB005875
Publisher site
See Article on Publisher Site

Abstract

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 (“δ15N”) exist from the South Pacific. Here we present measurements of the concentration and δ15N of DON collected in the eastern tropical South Pacific during the austral summers of 2010 (El Niño) and 2011 (La Niña). The concentration and δ15N of DON from the eastern tropical South Pacific are broadly consistent with prior measurements elsewhere, that is, DON concentrations of 5 ± 1 μM and DON δ15N of 5 ± 1‰, 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 δ15N were significantly negatively correlated (r = −0.84, p = 0.0006), indicating that DON was consumed in surface waters with an isotope effect of 5.5 ± 1.2‰. 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.

Journal

Global Biogeochemical CyclesWiley

Published: Jan 1, 2018

Keywords: ; ; ; ; ;

References

You’re reading a free preview. Subscribe to read the entire article.


DeepDyve is your
personal research library

It’s your single place to instantly
discover and read the research
that matters to you.

Enjoy affordable access to
over 18 million articles from more than
15,000 peer-reviewed journals.

All for just $49/month

Explore the DeepDyve Library

Search

Query the DeepDyve database, plus search all of PubMed and Google Scholar seamlessly

Organize

Save any article or search result from DeepDyve, PubMed, and Google Scholar... all in one place.

Access

Get unlimited, online access to over 18 million full-text articles from more than 15,000 scientific journals.

Your journals are on DeepDyve

Read from thousands of the leading scholarly journals from SpringerNature, Elsevier, Wiley-Blackwell, Oxford University Press and more.

All the latest content is available, no embargo periods.

See the journals in your area

DeepDyve

Freelancer

DeepDyve

Pro

Price

FREE

$49/month
$360/year

Save searches from
Google Scholar,
PubMed

Create lists to
organize your research

Export lists, citations

Read DeepDyve articles

Abstract access only

Unlimited access to over
18 million full-text articles

Print

20 pages / month

PDF Discount

20% off