Rodgers K. B., Aumont Olivier, Toyama K., Resplandy L., Ishii M., Nakano T., Sasano D., Bianchi D., Yamaguchi R. (2024). Low-latitude mesopelagic nutrient recycling controls productivity and export. Nature, 632 (8026), p. [19 p.]. ISSN 0028-0836.
Titre du document
Low-latitude mesopelagic nutrient recycling controls productivity and export
Année de publication
2024
Auteurs
Rodgers K. B., Aumont Olivier, Toyama K., Resplandy L., Ishii M., Nakano T., Sasano D., Bianchi D., Yamaguchi R.
Source
Nature, 2024,
632 (8026), p. [19 p.] ISSN 0028-0836
Low-latitude (LL) oceans account for up to half of global net primary production and export(1,2,3,4,5). It has been argued that the Southern Ocean dominates LL primary production and export(6), with implications for the response of global primary production and export to climate change(7). Here we applied observational analyses and sensitivity studies to an individual model to show, instead, that 72% of LL primary production and 55% of export is controlled by local mesopelagic macronutrient cycling. A total of 34% of the LL export is sustained by preformed macronutrients supplied from the Southern Ocean via a deeper overturning cell, with a shallow preformed northward supply, crossing 30 degrees S through subpolar and thermocline water masses, sustaining only 7% of the LL export. Analyses of five Coupled Model Intercomparison Project Phase 6 (CMIP6) models, run under both high-emissions low-mitigation (shared socioeconomic pathway (SSP5-8.5)) and low-emissions high-mitigation (SSP1-2.6) climate scenarios for 1850-2300, revealed significant across-model disparities in their projections of not only the amplitude, but also the sign, of LL primary production. Under the stronger SSP5-8.5 forcing, with more substantial upper-ocean warming, the CMIP6 models that account for temperature-dependent remineralization promoted enhanced LL mesopelagic nutrient retention under warming, with this providing a first-order contribution to stabilizing or increasing, rather than decreasing, LL production under high emissions and low mitigation. This underscores the importance of a mechanistic understanding of mesopelagic remineralization and its sensitivity to ocean warming for predicting future ecosystem changes.
Plan de classement
Sciences du milieu [021]
;
Limnologie physique / Océanographie physique [032]
;
Ecologie, systèmes aquatiques [036]
Description Géographique
OCEAN AUSTRAL, ATLANTIQUE ; PACIFIQUE ; OCEAN INDIEN
Localisation
Fonds IRD [F B010091288]
Identifiant IRD
fdi:010091288
