High resolution in-situ nutrient analysis: Development of a nitrate sensor

Understanding the water column nutrient dynamics is fundamental to quantifying primary productivity and the assessment of water quality. Nutrients such as nitrate ammonia and phosphate are typically evaluated from field samples, collected, transported, stored and analysed in the lab. Sample processing is time consuming and impractical for studies requiring high spatial and/or temporal resolution. In addition, sample handling and storage can introduce contamination and analysis errors. This paper discusses the development of a engineering prototype, the chemical process, testing and the deployment of a high resolution nitrate sensor. The mechanical, electrical and control systems are reviewed in detail. Data analysis and processing is also discussed. Preliminary sensor results are presented and compared to conventional sampling techniques. Finally, the paper outlines future work and improvements.