Date of Award

8-2002

Level of Access Assigned by Author

Open-Access Thesis

Degree Name

Master of Science (MS)

Department

Oceanography

Advisor

Fei Chai

Second Committee Member

David W. Townsend

Third Committee Member

Huijie Xue

Abstract

Monterey Bay is an upwelling region with high biological productivity in the California Coastal Current System. Several moorings, developed and maintained by the Monterey Bay Aquarium Research Institute (MBARI), have produced a long-term, highquality time series oceanographic data set for the Monterey Bay. The data set has revealed a more comprehensive picture of physical-biological interaction on seasonal and interannual variability. To improve our understanding of how the marine ecosystem responds to physical forcing, especially upwelling, an open ocean ecosystem model was modified for the Monterey Bay upwelling region. The result was a nine-component ecosystem model of Monterey Bay, which produced simulated results comparable to the observations. The model included three nutrients (silicate, nitrate, and ammonia), two phytoplankton groups (small phytoplankton and diatoms), two zooplankton grazers (microzooplankton and mesozooplankton), and two detrital pools (silicon and nitrogen). The observed upwelling velocity, nutrient concentrations at the base of the euphotic zone (40m), and solar radiation at the ocean surface were used to force the ecosystem model. Through model and data comparison, as well as sensitivity studies testing ecosystem parameters, the model was capable of detailing the seasonal cycle of nutrient dynamics and phytoplankton productivity, as well as interannual variability, including El Nifio Southern Oscillation (ENSO) impacts on biological productivity in the Monterey Bay.

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