ABSTRACT
Natural waters are complex physical-chemical-biological media comprising living, non-living, and once-living material that may be present in aqueous solution or in aqueous suspension. In the consideration of natural water, pure water is taken to imply water that is free from the optical effects of terrestrially and/or atmospherically derived organic and inorganic matter. Molecular scattering, however, from the pure water/dissolved salt combination assumes greater significance when specific directional scattering is considered. Dissolved organic matter concentrations in natural waters are consequences of either photosynthetic activity of phytoplankton or direct inputs of terrestrially derived matter. All natural water bodies inescapably contain a suspended matter component comprised of organic and inorganic material under the collective term seston. It is widely observed that the relative populations of the phytoplankton classifications comprising natural water bodies display a strong and predictable seasonal cycling, with each of the seasons displaying specific phytoplankton population compositions.
