Timing of the anthropogenic carbon invasion in the Southern California Current
- 1Centro de Investigación Científica y de Educación Superior de Ensenada (Ensenada, Mexico)
Abstract
The Eastern Boundary Upwelling Systems (EBUS), such as the Southern California Current System (CCS), are well-known high-productivity regions driven by alongshore winds, although their role as oceanic sources and sinks of atmospheric CO ₂ in the global carbon cycle is poorly understood. In the southern CCS, off Baja California, wind-driven vertical mixing upwells nutrient and carbon-rich waters from late winter to early summer, while weaker winds during the rest of the year allow the intrusion of nutrients and carbon-depleted subtropical surface waters. Here, we interpret the isotopic composition of organic carbon and calcitic records spanning ∼ 160 years from high-resolution sediment cores collected off Baja California, showing a clear trend toward lighter carbon isotopic compositions of the organic and inorganic carbon for the past seven decades. These trends are similar to the atmospheric records associated with the ¹³ C Suess effect, suggesting an atmospheric carbon invasion into the surface waters of the California Current. Nevertheless, the slope of the atmospheric carbon isotopic records is steeper than our marine record, most likely related to the upward mixing of subsurface waters with a relatively heavier carbon isotopic signature and advection processes inherent to the strong seasonality of the CCS southern boundary. These results will allow a better characterization of the relative role of the EBUS regions in the global carbon cycle.
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BibTeX
@article{contreraspacheco2026timing,
title = {{Timing of the anthropogenic carbon invasion in the Southern California Current}},
author = {Yéssica Vanessa Contreras-Pacheco and Jose Luis Abella-Gutiérrez and Gerardo Vallejo-Espinosa and Juan Carlos Herguera-García},
journal = {Biogeosciences},
year = {2026},
month = oct,
doi = {10.5194/bg-23-7397-2026},
url = {https://bg.copernicus.org/articles/23/7397/2026/},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Timing of the anthropogenic carbon invasion in the Southern California Current
AU - Yéssica Vanessa Contreras-Pacheco
AU - Jose Luis Abella-Gutiérrez
AU - Gerardo Vallejo-Espinosa
AU - Juan Carlos Herguera-García
PY - 2026
DA - 2026/10/23
JO - Biogeosciences
DO - 10.5194/bg-23-7397-2026
UR - https://bg.copernicus.org/articles/23/7397/2026/
AB - The Eastern Boundary Upwelling Systems (EBUS), such as the Southern California Current System (CCS), are well-known high-productivity regions driven by alongshore winds, although their role as oceanic sources and sinks of atmospheric CO ₂ in the global carbon cycle is poorly understood. In the southern CCS, off Baja California, wind-driven vertical mixing upwells nutrient and carbon-rich waters from late winter to early summer, while weaker winds during the rest of the year allow the intrusion of nutrients and carbon-depleted subtropical surface waters. Here, we interpret the isotopic composition of organic carbon and calcitic records spanning ∼ 160 years from high-resolution sediment cores collected off Baja California, showing a clear trend toward lighter carbon isotopic compositions of the organic and inorganic carbon for the past seven decades. These trends are similar to the atmospheric records associated with the ¹³ C Suess effect, suggesting an atmospheric carbon invasion into the surface waters of the California Current. Nevertheless, the slope of the atmospheric carbon isotopic records is steeper than our marine record, most likely related to the upward mixing of subsurface waters with a relatively heavier carbon isotopic signature and advection processes inherent to the strong seasonality of the CCS southern boundary. These results will allow a better characterization of the relative role of the EBUS regions in the global carbon cycle.
SN - 1726-4189
SN - 1726-4170
ER -