Underwater spectrophotometric detection: Scaling down ocean acidification monitoring

The increasing demand for monitoring capabilities required by ocean acidification survey programs is forcing sensor developers to find suitable arrangements for long-term, drift-free deployments. The increasing application of microtechnology will help the development of fault-free, calibration-free solid state probes. Spectrophotometry already helps oceanographers in retrieving fundamental datasets of high quality data about the status of ocean health, both in surface and deep water, and including carbon bio-geochemistry. This work describes the advancements on two spectrophotometric flow-through devices optimized for pH and carbonate detection with accuracy limited by the knowledge of equilibrium properties of reagents in seawater.