The Biowatt Program is an interdisciplinary program sponsored by the Office of Naval Research (ONR). One of its primary objectives is to develop predictive models of the temporal and spatial variability of optical properties and bioluminescence in the open ocean. An introduction to Biowatt and a conceptual model for the program were presented by Marra and Hartwig . This model illustrates the causal links between physical, biological, and optical processes in the upper oceans that control the variability of optical and bioluminescent properties. For example, inputs of light, momentum, and heat from the atmosphere can help redistribute phytoplankton, zooplankton, plant nutrients, and other biogenic materials. In turn, this redistribution of biogenic properties can affect the optical properties and physics of the upper ocean. Populations of bioluminescent organisms and their bioluminescent activity are also affected either directly or indirectly by variations in the physical, biological, and optical environment. Clearly, there are many complex interactions and feedback loops that must be included in the Biowatt model.