The Marine Science Institute of the University of Texas, with continuous use by resident research staff since 1946, is the oldest marine laboratory on the Texas Gulf Coast. The Institute has excellent facilities, and eight new research staff have been hired in the past three years. This project will provide funds for two essential pieces of multi-user equipment currently lacking at the site: an image analysis sytem and an inverted epifluorescence microscope. These items are needed by scientists studying marine bacteria, phytoplankton, zooplankton and ichthyoplankton to help characterize field-collected samples to estimate biomass, productivity, trophic relationships and species diversity. Computer enhanced video images provide several improvements to traditional enumeration and characterization of samples, with the added advantages of greater accuracy and faster processing. Image analysis in combination with fluorescence microscopy and appropriate stains or labelled probes can be used to rapidly characterize size, trophic level, taxonomy and physiology of marine microbes. The Institute will house the equipment in a newly created center for image and motion analysis. The center will provide a unique opportunity for both visiting investigators and resident staff to characterize and analyze preserved samples or prepared slides using image analysis, or to study the behavior of living organisms using motion analysis.