How is climate change affecting Cordell Bank?

The Foundation funds the long-term monitoring that helps answer this question.

As waters warm, the ability of the ocean to hold oxygen decreases. Warming waters also cause the ocean to form distinct layers, reducing mixing and limiting the exchange of oxygen and nutrients. The global ocean has already experienced a 2% decline in oxygen since 1960 and is predicted to decline up to another 3-4% by 2100. Low oxygen conditions, called hypoxia, have become increasingly common in the ocean off California in recent years. Ocean oxygen concentrations off California have fallen 20% since 1980 and may fall below the range of natural variability by 2030. The deepest parts of Cordell Bank National Marine Sanctuary are naturally low in oxygen, but shallow areas are also experiencing low oxygen events for short periods in some years. Upwelling brings low oxygen water to the surface and plankton blooms fueled by upwelled nutrients can further reduce oxygen levels when they use oxygen at night or decay. Decreased ocean oxygen globally, and changes to the supply of oxygen to deep waters as a result of climate change, are producing upwelled water that is even lower in oxygen than in the past with direct impacts on oxygen concentrations in the Sanctuary.

Direct effects from hypoxia to organisms in the deep sea are less well understood but could increase stress and shrink available habitat. Economically important species like Dungeness crab and rockfish have been shown to move away from hypoxic areas and future conditions could reduce the available habitat for these species. Decreased oxygen could also lead to an increase in species that can thrive in these conditions such as Humboldt squid, which prey on economically important species. As hypoxic conditions become more widespread in the coming century, effects such as these are likely to become more common in the sanctuary. The long-term hypoxia monitoring funded by the Foundation is integral to learning about these changes and their implications for marine wildlife. 

To read the full report about climate change impacts to Cordell Bank National Marine Sanctuary, go to: https://sanctuaries.noaa.gov/management/climate/impact-profiles.html