Longitudinal variability of size-fractionated N-2 fixation and DON release rates along 24.5 degrees N in the subtropical North Atlantic
Dinitrogen (N-2) fixation and dissolved organic nitrogen (DON) release rates were measured on fractionated samples (>10 mu m and m) along 24.5 degrees N in the subtropical North Atlantic. Net N-2 fixation rates (N-2 assimilation into biomass) ranged from 0.01 to 0.4 nmol N L-1 h(-1), and DON rele...
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ftwilliammarycol:oai:scholarworks.wm.edu:vimsarticles-1257 2024-06-23T07:55:05+00:00 Longitudinal variability of size-fractionated N-2 fixation and DON release rates along 24.5 degrees N in the subtropical North Atlantic Benavides, Mar Bronk, Deborah A. Agawin, Nona S.R. Perez-Hernandez, M. Dolores Hernandez-Guerra, Alonso Aristegui, Javier 2013-01-01T08:00:00Z application/pdf https://scholarworks.wm.edu/vimsarticles/258 doi: 10.1002/jgrc.20253 https://scholarworks.wm.edu/context/vimsarticles/article/1257/viewcontent/jgrc.20253.pdf unknown W&M ScholarWorks https://scholarworks.wm.edu/vimsarticles/258 doi: 10.1002/jgrc.20253 https://scholarworks.wm.edu/context/vimsarticles/article/1257/viewcontent/jgrc.20253.pdf VIMS Articles diazotrophy DON release dissolved N-15(2) unicellular diazotrophs Saharan dust Physical Sciences Peer-Reviewed Articles Marine Biology text 2013 ftwilliammarycol https://doi.org/10.1002/jgrc.20253 2024-06-05T03:30:42Z Dinitrogen (N-2) fixation and dissolved organic nitrogen (DON) release rates were measured on fractionated samples (>10 mu m and m) along 24.5 degrees N in the subtropical North Atlantic. Net N-2 fixation rates (N-2 assimilation into biomass) ranged from 0.01 to 0.4 nmol N L-1 h(-1), and DON release rates ranged from 0.001 to 0.09 nmol N L-1 h(-1). DON release represented approximate to 14% and approximate to 23% of >10 mu m and (assimilation into biomass plus DON release), respectively. This implies that by overlooking DON release, N-2 fixation rates are underestimated. Net N-2 fixation rates were higher in the east and decreased significantly toward the west (r(s)=-0.487, p=0.002, and r(s)=-0.496, p=0.001, for the >10 mu m and fractions, respectively). The sum of both fractions correlated with aerosol optical depth at 550 nm (AOD 550 nm) (r(s)=0.382, p=0.017) and phosphate (PO43-) concentrations (r(s)=0.453, p=0.018), suggesting an enhancement of diazotrophy as a response to aerosol inputs and phosphorus availability. In contrast, DON release was constant among size fractions and did not correlate with any of these variables. We also compared N-2 fixation rates obtained using the N-15(2) dissolved and bubble methods. The first gave average rates 50% (49% 39) higher than the latter, which supports the finding that previously published N-2 fixation rates are likely underestimated. We suggest that by combining N-2 fixation and DON release measurements using dissolved N-15(2), global N-2 fixation rates could increase enough to balance oceanic fixed nitrogen budget disequilibria. Text North Atlantic W&M ScholarWorks Journal of Geophysical Research: Oceans 118 7 3406 3415 |
institution |
Open Polar |
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W&M ScholarWorks |
op_collection_id |
ftwilliammarycol |
language |
unknown |
topic |
diazotrophy DON release dissolved N-15(2) unicellular diazotrophs Saharan dust Physical Sciences Peer-Reviewed Articles Marine Biology |
spellingShingle |
diazotrophy DON release dissolved N-15(2) unicellular diazotrophs Saharan dust Physical Sciences Peer-Reviewed Articles Marine Biology Benavides, Mar Bronk, Deborah A. Agawin, Nona S.R. Perez-Hernandez, M. Dolores Hernandez-Guerra, Alonso Aristegui, Javier Longitudinal variability of size-fractionated N-2 fixation and DON release rates along 24.5 degrees N in the subtropical North Atlantic |
topic_facet |
diazotrophy DON release dissolved N-15(2) unicellular diazotrophs Saharan dust Physical Sciences Peer-Reviewed Articles Marine Biology |
description |
Dinitrogen (N-2) fixation and dissolved organic nitrogen (DON) release rates were measured on fractionated samples (>10 mu m and m) along 24.5 degrees N in the subtropical North Atlantic. Net N-2 fixation rates (N-2 assimilation into biomass) ranged from 0.01 to 0.4 nmol N L-1 h(-1), and DON release rates ranged from 0.001 to 0.09 nmol N L-1 h(-1). DON release represented approximate to 14% and approximate to 23% of >10 mu m and (assimilation into biomass plus DON release), respectively. This implies that by overlooking DON release, N-2 fixation rates are underestimated. Net N-2 fixation rates were higher in the east and decreased significantly toward the west (r(s)=-0.487, p=0.002, and r(s)=-0.496, p=0.001, for the >10 mu m and fractions, respectively). The sum of both fractions correlated with aerosol optical depth at 550 nm (AOD 550 nm) (r(s)=0.382, p=0.017) and phosphate (PO43-) concentrations (r(s)=0.453, p=0.018), suggesting an enhancement of diazotrophy as a response to aerosol inputs and phosphorus availability. In contrast, DON release was constant among size fractions and did not correlate with any of these variables. We also compared N-2 fixation rates obtained using the N-15(2) dissolved and bubble methods. The first gave average rates 50% (49% 39) higher than the latter, which supports the finding that previously published N-2 fixation rates are likely underestimated. We suggest that by combining N-2 fixation and DON release measurements using dissolved N-15(2), global N-2 fixation rates could increase enough to balance oceanic fixed nitrogen budget disequilibria. |
format |
Text |
author |
Benavides, Mar Bronk, Deborah A. Agawin, Nona S.R. Perez-Hernandez, M. Dolores Hernandez-Guerra, Alonso Aristegui, Javier |
author_facet |
Benavides, Mar Bronk, Deborah A. Agawin, Nona S.R. Perez-Hernandez, M. Dolores Hernandez-Guerra, Alonso Aristegui, Javier |
author_sort |
Benavides, Mar |
title |
Longitudinal variability of size-fractionated N-2 fixation and DON release rates along 24.5 degrees N in the subtropical North Atlantic |
title_short |
Longitudinal variability of size-fractionated N-2 fixation and DON release rates along 24.5 degrees N in the subtropical North Atlantic |
title_full |
Longitudinal variability of size-fractionated N-2 fixation and DON release rates along 24.5 degrees N in the subtropical North Atlantic |
title_fullStr |
Longitudinal variability of size-fractionated N-2 fixation and DON release rates along 24.5 degrees N in the subtropical North Atlantic |
title_full_unstemmed |
Longitudinal variability of size-fractionated N-2 fixation and DON release rates along 24.5 degrees N in the subtropical North Atlantic |
title_sort |
longitudinal variability of size-fractionated n-2 fixation and don release rates along 24.5 degrees n in the subtropical north atlantic |
publisher |
W&M ScholarWorks |
publishDate |
2013 |
url |
https://scholarworks.wm.edu/vimsarticles/258 https://scholarworks.wm.edu/context/vimsarticles/article/1257/viewcontent/jgrc.20253.pdf |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_source |
VIMS Articles |
op_relation |
https://scholarworks.wm.edu/vimsarticles/258 doi: 10.1002/jgrc.20253 https://scholarworks.wm.edu/context/vimsarticles/article/1257/viewcontent/jgrc.20253.pdf |
op_doi |
https://doi.org/10.1002/jgrc.20253 |
container_title |
Journal of Geophysical Research: Oceans |
container_volume |
118 |
container_issue |
7 |
container_start_page |
3406 |
op_container_end_page |
3415 |
_version_ |
1802647488704806912 |