Lateral advection supports nitrogen export in the oligotrophic open-ocean Gulf of Mexico

Kelly, Thomas B.; Knapp, Angela N.; Landry, Michael R.; Selph, Karen E.; Shropshire, Taylor A.; Thomas, Rachel K.; Stukel, Michael R.

doi:10.1038/s41467-021-23678-9

i

Lateral advection supports nitrogen export in the oligotrophic open-ocean Gulf of Mexico

2021
By Kelly, Thomas B. ; Knapp, Angela N. ; Landry, Michael R. ; ...

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Journal Title:

Nature Communications
Personal Author:

Kelly, Thomas B. ; Knapp, Angela N. ; Landry, Michael R. ; Selph, Karen E. ; Shropshire, Taylor A. ; Thomas, Rachel K. ; Stukel, Michael R.
NOAA Program & Office:

OAR (Oceanic and Atmospheric Research) ; NMF (National Marine Fisheries Service) ; SEFSC (Southeast Fisheries Science Center) ; CIMAS (Cooperative Institute for Marine and Atmospheric Studies) ; JIMAR (Joint Institute for Marine and Atmospheric Research) ; CIMEAS (Cooperative Institute for Marine, Earth, and Atmospheric Systems)
Description:

In contrast to its productive coastal margins, the open-ocean Gulf of Mexico (GoM) is notable for highly stratified surface waters with extremely low nutrient and chlorophyll concentrations. Field campaigns in 2017 and 2018 identified low rates of turbulent mixing, which combined with oligotrophic nutrient conditions, give very low estimates for diffusive flux of nitrate into the euphotic zone (< 1 µmol N m−2 d−1). Estimates of local N2-fixation are similarly low. In comparison, measured export rates of sinking particulate organic nitrogen (PON) from the euphotic zone are 2 – 3 orders of magnitude higher (i.e. 462 – 1144 µmol N m−2 d−1). We reconcile these disparate findings with regional scale dynamics inferred independently from remote-sensing products and a regional biogeochemical model and find that laterally-sourced organic matter is sufficient to support >90% of open-ocean nitrogen export in the GoM. Results show that lateral transport needs to be closely considered in studies of biogeochemical balances, particularly for basins enclosed by productive coasts.
Keywords:

Chlorophyll Nitrogen Lateral transport
Source:

Nat Commun 12, 3325
DOI:

https://doi.org/10.1038/s41467-021-23678-9
Document Type:

Journal Article
Funding:

Grant no. NA15OAR4320071 ; Grant no. NA16NMF4320058 ; Grant no. NA15OAR4320064
Place as Subject:

Mexico, Gulf of
License:

https://creativecommons.org/licenses/by/4.0/
Rights Information:

CC BY
Compliance:

Submitted
Main Document Checksum:

urn:sha256:1378ecf329c37114bc0c8d1902066bb23832f6b24786590c00c8a605d50d6b19
Download URL:

https://repository.library.noaa.gov/view/noaa/34229/noaa_34229_DS1.pdf
File Type:

[PDF - 1.83 MB ]

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