Oxygen declines and the shoaling of the hypoxic boundary in the California Current
Article first published online: 28 JUN 2008
Copyright 2008 by the American Geophysical Union.
Geophysical Research Letters
Volume 35, Issue 12, 28 June 2008
How to Cite
2008), Oxygen declines and the shoaling of the hypoxic boundary in the California Current, Geophys. Res. Lett., 35, L12607, doi:10.1029/2008GL034185., , , , , , and (
- Issue published online: 28 JUN 2008
- Article first published online: 28 JUN 2008
- Manuscript Accepted: 30 APR 2008
- Manuscript Received: 31 MAR 2008
- California Current System;
- dissolved oxygen;
- oxygen minimum layer;
 We use hydrographic data from the California Cooperative Oceanic Fisheries Investigations program to explore the spatial and temporal variability of dissolved oxygen (DO) in the southern California Current System (CCS) over the period 1984–2006. Large declines in DO (up to 2.1 μmol/kg/y) have been observed throughout the domain, with the largest relative DO declines occurring below the thermocline (mean decrease of 21% at 300 m). Linear trends were significant (p < 0.05) at the majority of stations down to 500 m. The hypoxic boundary (∼60 μmol/kg) has shoaled by up to 90 m within portions of the southern CCS. The observed trends are consistent with advection of low-DO waters into the region, as well as decreased vertical oxygen transport following near-surface warming and increased stratification. Expansion of the oxygen minimum layer could lead to cascading effects on benthic and pelagic ecosystems, including habitat compression and community reorganization.