The ability to develop and deploy biological sensors in nearshore waters to detect health threats such as from microbial pathogens and harmful algal blooms will enable more rapid response to health risks and improve the ability to open and close beaches and/or fisheries during periods of high risk. Advanced technologies such as the Environmental Sample Processor (ESP) developed by the Monterey Bay Research Aquarium (MBARI) are at hand. The ESP is a fully automated platform for in-situ sampling and genetic analysis. It can collect and concentrate water samples, extract nucleic acids, apply molecular probes to identify microorganisms, and relay the results back to shore. ESP deployments will be used as observatories and early-warning systems. NOAA is working with MBARI, Stanford University, and the Southern California Coastal Water Quality Program (SCCWRP) to improve ESP detection of microbial contaminants in coastal waters, with an emphasis on improving the qua lity and yield of nucleic acid extraction from coastal waters.