The role of minerogenic particles in light scattering in several lakes and a river (total of ten sites) in central New York, which represent a robust range of scattering conditions, was evaluated based on an individual particle analysis technique of scanning electron microscopy interfaced with automated x-ray microanalysis and image analysis (SAX), in situ bulk measurements of particle scattering and backscattering coefficients and ), and laboratory analyses of common indicators of scattering. SAX provided characterizations of the elemental x-ray composition, number concentration, particle size distribution (PSD), shape, and projected area concentration of minerogenic particles of sizes . Mie theory was applied to calculate the minerogenic components of and with SAX data. Differences in , associated primarily with clay minerals and , were responsible for most of the measured differences in both and across the study sites. Contributions of the specified minerogenic particle classes to were found to correspond approximately to their contributions to . The estimates of represented substantial fractions of , whereas those of were the dominant component of . The representativeness of the estimates of and was supported by their consistency with the bulk measurements. Greater uncertainty prevails for the estimates than those for , associated primarily with reported deviations in particle shapes from sphericity. The PSDs were well represented by the “B” component of the two-component model or a three parameter generalized gamma distribution [Deep-Sea Res. Part I 40, 1459 (1993)]. The widely applied Junge (hyperbolic) function performed poorly in representing the PSDs and the size dependency of light scattering in these systems, by overrepresenting the concentrations of submicrometer particles especially. Submicrometer particles were not important contributors to or .
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