@article{d42bec37ff1041e99cf193bb9c92b647,
title = "Nutrient Controls on Export Production in the Southern Ocean",
abstract = "We use observations from novel biogeochemical profiling floats deployed by the Southern Ocean Carbon and Climate Observations and Modeling program to estimate annual net community production (ANCP; associated with carbon export) from the seasonal drawdown of mesopelagic oxygen and surface nitrate in the Southern Ocean. Our estimates agree with previous observations in showing an increase in ANCP in the vicinity of the polar front (∼3 mol C m−2 y−1), compared to lower rates in the subtropical zone (≤ 1 mol C m−2 y−1) and the seasonal ice zone (<2 mol C m−2 y−1). Paradoxically, the increase in ANCP south of the subtropical front is associated with elevated surface nitrate and silicate concentrations, but decreasing surface iron. We hypothesize that iron limitation promotes silicification in diatoms, which is evidenced by the low silicate to nitrate ratio of surface waters around the Antarctic polar front. High diatom silicification increases the ballasting effect of particulate organic carbon and overall ANCP in this region. A model-based assessment of our methods shows a good agreement between ANCP estimates based on oxygen and nitrate drawdown and the modeled downward organic carbon flux at 100 m. This agreement supports the presumption that net biological consumption is the dominant process affecting the drawdown of these chemical tracers and that, given sufficient data, ANCP can be inferred from observations of oxygen and/or nitrate drawdown in the Southern Ocean.",
keywords = "carbon, export, limitation, nutrient, phytoplankton",
author = "Arteaga, {Lionel A.} and Markus Pahlow and Bushinsky, {Seth M.} and Sarmiento, {Jorge Louis}",
note = "Funding Information: We would like to thank the many people at the Monterey Bay Aquarium Research Institute, the University of Washington, and the University of Maine who quality controlled and corrected the SOCCOM float data. SOCCOM float data were collected and made freely available by the Southern Ocean Carbon and Climate Observations and Modeling (SOCCOM) Project funded by the National Science Foundation, Division of Polar Programs (NSF PLR-1425989), supplemented by NOAA and NASA (PI Jorge Sarmiento). L. Arteaga is mainly supported by NASA under Award NNX17AI73G. S. M. Bushinsky is supported by the SOCCOM project, NASA (NNX17AI73G), and the Carbon Mitigation Initiative (CMI) project sponsored by BP at Princeton University. M. Pahlow was supported by Deutsche Forschungsgemeinschaft (DFG) project SFB754 (Sonderforschungsbereich 754 “Climate-Biogeochemistry Interactions in the Tropical Ocean,” www.sfb754.de). We would also like to thank Rick Slater for providing CM2-1° output to evaluate our methodology. All details and web addresses needed to access the data used to produce our results are described in section of this paper. Funding Information: We would like to thank the many people at the Monterey Bay Aquarium Research Institute, the University of Washington, and the University of Maine who quality controlled and corrected the SOCCOM float data. SOCCOM float data were collected and made freely available by the Southern Ocean Carbon and Climate Observations and Modeling (SOCCOM) Project funded by the National Science Foundation, Division of Polar Programs (NSF PLR‐1425989), supplemented by NOAA and NASA (PI Jorge Sarmiento). L. Arteaga is mainly supported by NASA under Award NNX17AI73G. S. M. Bushinsky is supported by the SOCCOM project, NASA (NNX17AI73G), and the Carbon Mitigation Initiative (CMI) project sponsored by BP at Princeton University. M. Pahlow was supported by Deutsche Forschungsgemeinschaft (DFG) project SFB754 (Sonderforschungsbereich 754 “Climate‐Biogeochemistry Interactions in the Tropical Ocean,” www.sfb754.de ). We would also like to thank Rick Slater for providing CM2‐1° output to evaluate our methodology. All details and web addresses needed to access the data used to produce our results are described in section of this paper. Publisher Copyright: {\textcopyright}2019. American Geophysical Union. All Rights Reserved.",
year = "2019",
month = aug,
day = "1",
doi = "10.1029/2019GB006236",
language = "English (US)",
volume = "33",
pages = "942--956",
journal = "Global Biogeochemical Cycles",
issn = "0886-6236",
publisher = "American Geophysical Union",
number = "8",
}