Chlorophyll Dynamics in the Southern California Bight

Craig Gelpi, Catalina Marine Society, Lake Balboa, CA, United States
We analyze a multi-year time series of MODIS chlorophyll product at high spatial resolution to determine spatial and temporal dynamics of chlorophyll in the Southern California Bight. These dynamics are compared to advection and upwelling patterns as well as to the average vertical eddy diffusion coefficient for the center of the Bight. We find the most chl-a events as well as the maximum values of chl-a to be in the Santa Barbara Channel. This source of chl-a is advected southeast to engulf San Nicolas Island, making the region surrounding this island to be the most chlorophyll rich among the Southern Channel Islands. In contrast, the other major Southern Channel Islands, San Clemente, Santa Barbara and Santa Catalina, do not exhibit any local enhancement in chlorophyll. Chl-a is found to have annual cycles in the region of the Southern Channel Islands that initialize nearly simultaneously in late winter or spring. However, the local blooms at Santa Catalina commence earlier, are shorter lived and do not attained the maximum chl-a values found at San Nicolas.