A nutrient relay sustains subtropical ocean productivity
Name
pnas.2206504119.pdf
Description
Published version
Size
2.24 MB
Format
Adobe PDF
Checksum (MD5)
a8be75c145f567c47180acbba86dc36b
Author(s)
Gupta, Mukund
Williams, Richard G
Lauderdale, Jonathan M
Jahn, Oliver
Hill, Christopher
Dutkiewicz, Stephanie
Follows, Michael J
Date Issued
2022
Journal
Proceedings of the National Academy of Sciences of the United States of America
Publisher
Proceedings of the National Academy of Sciences
Citation
Gupta, Mukund, Williams, Richard G, Lauderdale, Jonathan M, Jahn, Oliver, Hill, Christopher et al. 2022. "A nutrient relay sustains subtropical ocean productivity." Proceedings of the National Academy of Sciences of the United States of America, 119 (41).
Version
Final published version
Abstract
The expansive gyres of the subtropical ocean account for a significant fraction of global organic carbon export from the upper ocean. In the gyre interior, vertical mixing and the heaving of nutrient-rich waters into the euphotic layer sustain local productivity, in turn depleting the layers below. However, the nutrient pathways by which these subeuphotic layers are themselves replenished remain unclear. Using a global, eddy-permitting simulation of ocean physics and biogeochemistry, we quantify nutrient resupply mechanisms along and across density surfaces, including the contribution of eddy-scale motions that are challenging to observe. We find that mesoscale eddies (10 to 100 km) flux nutrients from the shallow flanks of the gyre into the recirculating interior, through time-varying motions along density surfaces. The subeuphotic layers are ultimately replenished in approximately equal contributions by this mesoscale eddy transport and the remineralization of sinking particles. The mesoscale eddy resupply is most important in the lower thermocline for the whole subtropical region but is dominant at all depths within the gyre interior. Subtropical gyre productivity may therefore be sustained by a nutrient relay, where the lateral transport resupplies nutrients to the thermocline and allows vertical exchanges to maintain surface biological production and carbon export.
MIT Department
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
Terms of Use
Creative Commons Attribution 4.0 International license
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DOI of Published Version
https://doi.org/10.1073/PNAS.2206504119
