Consequences of Nearshore Low Oxygen and Low pH for Coastal Resources of Southern California

In this project, researchers are investigating the combined effects of low-oxygen, low-pH conditions on marine organisms living at depths between 20 meters and 300 meters off San Diego. Specific goals include mapping dissolved oxygen concentrations and water acidity to characterize the frequency, duration, extent and intensity of these conditions on seasonal and, if possible, weekly time scales. Maps of oxygen concentrations will be superimposed on squid egg- bed habitat maps to identify areas where the species may be susceptible to low-oxygen stress, particularly during its early life history stages. Through laboratory experiments and field collecting, researchers will estimate critical lethal and sublethal oxygen and pH thresholds for the market squid. These thresholds will be used, in conjunction with monitoring data, to identify areas where squid embryos may experience higher than normal mortalities. This work will address the hypothesis that market squid migrate or shift spawning grounds in response to dissolved oxygen concentrations. Results will provide valuable insights into the potential consequences of the shoaling of the oxygen minimum zone in the Southern California Bight on key marine resources with the California Current large marine ecosystem.