Inherent and apparent optical properties as measured in case 1 waters often deviate in seemingly random ways from values predicted by bio-optical models that parameterize the microbial composition of the water in terms of the chlorophyll concentration alone. We believe that this `random' variability in optical properties can be explained in terms of variability in the detailed microbial composition of the water, and we outline a research program for testing this hypothesis. Our approach combines laboratory experiments on monospecific microbial cultures, Mie scattering calculations, and radiative transfer numerical modeling. This approach also provides a unique means for improving bio-optical models and for developing new optical methods or algorithms for the study of biological processes in the upper ocean. We present here a few examples from preliminary results of this work. These examples show selected measures of the underwater light field for a hypothetical ocean that consists of pure water, viruses, heterotrophic bacteria, cyanobacteria, and small diatoms as optically significant components.