Spatial and temporal variability of Light attenuation within Florida Bay, USA was examined at 17 stations over a 1 yr period, with emphasis on the relative roles of algal and non-algal factors in the absorption of light in the water column. Four distinct regions in the bay were identified based on differences in the relationships between light extinction coefficients (K,), non-algal suspended solids (tripton), chlorophyll (chl) a, and color. Ranges of mean values for these key variables, at

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... vidual stations within the bay, were 0.66 to 2.82 m-' for K" 8.1 to 30 g m-3 for tripton, 0.4 to 18.4 mg m-3 for chl a and 1.4 to 15 pt units for color. These results are discussed in relation to light availability for planktonic and benthic primary production in different regions of the bay and seasons of the year. The results indicate a significant potential for light limitat~on of seayrass colonization in certain regions of the bay due to light attenuation in the water column caused by high levels of tripton and/or phytoplankton.