Testing and Refinement of Long Pathlength Liquid Core Waveguide Sensors for Autonomous In-Situ Analysis of the Upper Ocean

The broad objectives of this work are the testing, deployment and refinement of spectroscopic sensors for monitoring the distributions of reactive chemicals in seawater. The analytes of special interest in this work are iron, copper, nitrate, nitrite, ammonia, phosphate and CO2-system variables (total inorganic carbon, total alkalinity, CO2 partial pressure and pH). The desired accuracy of the in-situ instrumentation is 0.1%, and the anticipated limit of detection for micronutrients is better than one nanomolar. The sensors should be capable of autonomous operations on a wide variety of platforms including AUVs, profiling floats, gliders and moorings.