Abstract

This paper examines the relationships between fluxes of biogenic siliceous microparticles and two indices of climatology and regional oceanography in the Santa Barbara Channel. As an index of large-scale processes, we use the Pacific Decadal Oscillation Index (PDO). As an index of small-scale processes, we use the first Empirical Orthoganal Function (EOF) of objectively mapped local circulation patterns. Local circulation is correlated with basin-wide climate. Results are consistent with the hypothesis that one influence of climate on phytoplankton flux is initially exerted through climate-driven effects on local circulation. The response of siliceous phytoplankton to changes in circulation and climate occurs relatively rapidly, over periods of a few weeks, consistent with flux being directly mediated by advection of waters from different sources. The maximum response of radiolarians to basin-wide conditions is delayed for several months, and appears to be more indirect than that of phytoplankton, perhaps buffered against environmental changes by differences in trophic level or depth range. Several flux events did not have apparent relationships with either oceanic climate or local oceanography. These anomalies lasted for one to four months and may represent the limits of resolution of flux data.