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Physical and Biogeochemical Drivers of Alongshore pH and Oxygen Variability in the California Current System
Author(s) -
Cheresh Julia,
Fiechter Jerome
Publication year - 2020
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2020gl089553
Subject(s) - upwelling , biogeochemical cycle , oceanography , hypoxia (environmental) , environmental science , ecosystem , advection , ocean acidification , current (fluid) , forcing (mathematics) , marine ecosystem , climate change , geology , oxygen , atmospheric sciences , ecology , environmental chemistry , chemistry , physics , organic chemistry , biology , thermodynamics
In the California Current System (CCS), the nearshore environment experiences natural exposure to low pH and reduced oxygen in response to coastal upwelling. Anthropogenic impacts further decrease pH and oxygen below biological thresholds, making the CCS particularly vulnerable to ocean acidification and hypoxia. Results from a coupled physical‐biogeochemical model reveal a strongly heterogeneous alongshore pattern of nearshore pH and oxygen in the central CCS, both in their long‐term means and trends. This spatial structuring is explained by an interplay between alongshore variability in local upwelling intensity and subsequent primary production, modulated by nearshore advection and regional geostrophic currents. The model solution suggests that the progression of ocean acidification and hypoxia will not be spatially homogeneous, thereby highlighting the need to consider subregional processes when assessing natural and anthropogenic impacts on coastal ecosystems in eastern boundary current upwelling regions.