Transitioning Submersible Chemical Analyzer Technologies for Sustained, Autonomous Observations From Profiling Moorings, Gliders and other AUVs

Grant nos. N00014-05-1-0649 and N00014-05-WX20853. Part of the National Oceanographic Partnership Program (NOPP). Prepared in collaboration with the Graduate School of Oceanography, University of Rhode Island, Narragansett, RI; WET Labs, Inc., Philomath, OR; and the Ocean Technology Branch Code 2744, Space and Naval Warfare (SPAWAR) Systems Center, San Diego, CA. The original document contains color images.

The long term goal is to transition existing prototype autonomous profiling nutrient analyzers into commercial products that can be readily deployed on autonomous profiling moorings, coastal gliders and propeller driven unmanned underwater vehicles and used for sustained, autonomous ocean observations of chemical distributions and variability. A series of issues have been identified that need to be addressed to convert prototype nutrient analyzers into commercial units that can be widely used by the community for sustained and accurate, stable, autonomous operation in the ocean. These issues are; (1) a more compact size, (2) reduced reagent and power consumption, (3) enhanced biofouling suppression, (4) ease of use by non-chemists, and (5) documented performance when deployed on different platforms. Our plan to address those issues involves using recent advances in micro-fluidics and optical detectors (new SubChem and WET Labs technologies) to reduce sample flow rates and volumes and thus reagent and power consumption; (2) extend the length of field deployments by periodically isolating sensitive components so that back-flushing and chemical techniques can be used to suppress biofouling, (3) increase the ease of use by simplifying operation, pre-packaging reagents and outputting the data in engineering units, and (4) thoroughly documenting the performance by conducting demonstration experiments at field sites that have strong vertical and horizontal nutrient gradients and episodic phytoplankton blooms.