The NASA Earth science program needs nutrient monitoring sensors (Topic S1.08). We will develop a submersible, inexpensive microfluidic inorganic nutrient analyzer for coastal and oceanic waters. The low fabrication cost of the proposed robust optical analyzer will allow for its global deployment, thus enhancing NASA¬øs research capabilities. Our nutrient analyzer will be designed to be deployed from a variety of stationary or mobile oceanographic platforms. The key advancements of our design are its extreme mechanical and optical robustness, and its ability to detect low (nanomolar) concentrations of analytes using colorimetric approaches. The robustness will be obtained by integrating all key elements in a glass monolith; and the sensibility will be reached by increasing the flowcell absorption pathlength, making it several orders of magnitude longer than that found on standard microfluidic devices. These advancements will enable the development of autonomous wet chemistry analyzers for open ocean applications using a variety of platforms and vehicles. We will initially monitor nitrites. Later on this will be extended to other nutrients such as ammonium and phosphate. The concentration of inorganic nutrients in aquatic environments is a fundamental water quality parameter needed for environmental assessment, ecological sciences, and ecosystem stewardship activities. There are growing needs for field-deployable nutrient analyzers designed to monitor nitrogen or phosphorus without the need for manual sample collection or manual attention to the instrument during operation. These needs are poorly addressed by the available commercial instruments owing to their complexity, large physical size, high power consumption and excessive reagent usage. Translume anticipates our nutrient analyzers will be of interest to two groups: (a) Researchers in organizations needing robust nutrient analyzers for oceanographic/ life science / and seawater research. NOAA, the Navy, watershed monitoring agencies and the makers of research gliders are potential users. There are also major opportunities associated with developments to pursue the use of algae as a biofuel source. This emerging industry will need a means to optimize algae growth, which could be served by a variant of our nutrient analyzers. (b) Regulatory agencies and regulated industries. EPA, water districts, municipal beach agencies, as well as petroleum and energy companies needing to monitor dead zones are also potential users.