Sanctuary Integrated Monitoring Network
National Marine Sanctuaries


Oceanography_ map
Figure 1. Oceanographic zones within the Monterey Bay, Gulf of the Farallones, and Cordell Bank National Marine Sanctuaries. [View Larger]
The oceanography of the northern California national marine sanctuaries is complex and the result of numerous factors. In particular, regional currents such as the California and Davidson Currents are very influential.

Local tidal currents and submarine and terrestrial physical features also influence the area's oceanographic environment. For example, local outflow from San Francisco Bay affects the Gulf of the Farallones sanctuary.

The calendar year in northern California waters consists of three general oceanographic seasons. Although these occur in each sanctuary at slightly different times (see specific details for Cordell Bank, Gulf of the Farallones and Monterey Bay), the seasons, as they pass through each sanctuary, are characterized by the same phenomena: Longer-term climatic variations, principally El Niño-Southern Oscillation (ENSO), the Pacific Decadal Oscillation (PDO) and global climate change, also affect local physical and biological systems.

ENSO refers to periodic cycling between anomalously warm (El Niño) and cool (La Niña) ocean water temperatures that spread across the equatorial Pacific Ocean. These anomalies indicate perturbations in the ocean and atmosphere that are manifested over broad scales, including the California Current ecosystem. Like ENSO, the PDO comprises a warm and a cool interval (associated with changes in surface water temperatures of several degrees), but over a longer period of time.

Conservation and Management Issues

Lowering a niskin bottle used for water quality sampling during a 2005 CIMT survey. Photo: CIMT

MBARI's M2 mooring. The sensors on this buoy collects various oceanographic and atmospheric measurements around the clock.

Offshore waters in the region are in relatively good condition, but nearshore coastal areas, harbors, lagoons, estuaries and tributaries show a number of problems, including elevated levels of coliform bacteria, detergents, oils, nitrates, sediments and persistent pesticides. These contaminants can have a variety of biological impacts - including bioaccumulation, reduced recruitment of anadramous species and transfer of human pathogens - as well as interference with recreational uses due to beach closures.

Phytoplankton blooms, including harmful algal blooms, have increased in frequency and distribution worldwide since 1980. The frequency of such blooms may be increasing with nutrient enrichment from agricultural and urban storm runoff as well as sewage effluent.


All three sanctuaries are involved in a variety of research and monitoring efforts.

PRBO Conservation Science, in collaboration with Cordell Bank and Gulf of the Farallones sanctuaries, study krill and oceanographic processes within these two sanctuaries: Cordell Bank staff are involved in two projects to learn more about regional oceanographic processes: The Gulf of the Farallones sanctuary is also involved in other oceanographic studies: Examples of the many projects underway with the Monterey Bay sanctuary include the following: