Relationship between chlorophyll a fluorescence and underwater light transmission in coastal waters off Southern California

The continuous measurement of underwater light attenuation was investigated as a means of estimating chlorophyll distributions in Southern California coastal waters. In contrast to previous studies at other locales, depth profiles showed that the volume attenuation coefficient ( a) covaried nonlinearly with chlorophyll a fluorescence. However, when measured over time at a fixed depth a and chlorophyll a fluorescence were observed to be linearly related. Results are consistent with a model that considers contributions to a from nonfluorescing particles whose distributions are influenced by thermal stratification of the water column.