Award: OCE-1414586

The major goal of the project was to develop a rugged, portable multi-parameter inorganic carbon analyzer (MICA) named MICA in a Box (MIB) to allow facile measurements of three of the primary parameters of the aqueous carbon dioxide (CO2) system: total dissolved inorganic carbon (DIC); total alkalinity (TA); and solution acidity (pH) during work along the shores of rivers and lakes and on research vessels. This multi-parameter sensor was designed to be easy to operate, highly portable, and require very little supporting infrastructure. MIB components are housed in an 18" x 13" water-tight Pelican case, allowing for rapid deployment in a wide range of environments. The self-contained system runs user-defined missions fully autonomously, has onboard batteries, and requires little external infrastructure. Reagent bags and the user interface display are mounted inside the case lid or cover. One half of the main case contains the measurement cells and fluidic components, while the other half houses the control electronics, light sources, batteries and pumps. A secondary lid covers the electronics to provide a protective barrier from water. Even though the MIB is not designed to be submerged, normal splashes and light rain should not have an impact on the instrument. The user interface provides a very straightforward display of measurement results and the ability to control instrument functions. During this project the MIB design and construction was completed, and extensive laboratory testing was performed to demonstrate full functionality. The MIB was then tested on the Gulf of Mexico Ecosystems and Carbon Cruise (GOMECC-3) onboard the R/V Ronald H. Brown in July and August 2017. Measurement accuracies and precisions for pH, DIC, and TA prior to the GOMECC-3 cruise were consistent with requirements for high-quality monitoring of ocean acidification. Unfortunately, early in the cruise, seawater leaks from fluidic connections within the MIB led to corrosion damage of many of the electronic components. The pH and TA measurement channels were subsequently restored to operation and over 61,000 measurements of underway pH and over 8500 measurements of underway TA were collected by the MIB during the remainder of GOMECC-3. However, after closer post-cruise inspection of the MIB data, comparison with MIB measurements of reference materials, and measurements from discrete collected samples using other methods, the underway MIB pH and TA data were determined to have been compromised by the corrosion damage. Nonetheless, MIB capabilities for automated continuous underway pH and TA measurements were demonstrated during the cruise, and the experience led to several concepts for design improvements. The cruise led to an improved understanding of the MIB system and promoted capabilities for construction of more ruggedized and fieldable MIB sensors. Future generations of MIB should ultimately have positive impacts on the ocean acidification community by making measurements of the marine carbon system readily accessible to a wider range of researchers than current technology permits. Our overarching objective is to make carbon system measurements as routine as salinity determinations. Last Modified: 08/10/2018 Submitted by: Robert H Byrne