Programme website: http://inspire-dtp.ac.uk
In order to investigate the oceanic carbonate system, four of its chemical parameters (pH, DIC = total dissolved inorganic carbon, TA = total alkalinity, pCO2) can be measured consistently and readily. Usually, determination of any two of these suffices to compute a suite of properties that describe the state of the oceanic carbonate system. One of the most reliably and routinely measured parameters is TA, which represents the ability of oceanic water to buffer pH changes with the addition of acids, most notably that which is generated by the invasion of CO2 from the atmosphere. While ex situ measuring TA and the other carbonate system parameters is an essential aspect of global ocean biogeochemistry, the technology for measuring TA accurately and precisely in situ is poorly developed. 
This project will contribute to filling this technology gap with the development of a microfluidic lab-on-chip sensor which can autonomously measure oceanic TA over a wide range of values. The small size and low resource consumption inherent in lab-on-chip technologies means that the resulting device could be placed on a wide range of ocean measurement platforms, including autonomous underwater vehicles and surface vehicles, for short and long time scale TA monitoring.
This project will explore the use of droplet microfluidics for performing automated TA measurements in seawater. Droplet microfluidics is a technique that allows the rapid creation, manipulation, and analysis of small (<µL) aqueous samples as droplets dispersed in an oil-filled channel. Relative to the current state-of-the-art (non-droplet) microfluidic chemical sensors, the droplet approach allows higher analytical throughput, a wider analytical range, and the ability to de-gas samples efficiently, making it a promising candidate for TA measurement. One of the project supervisors (AN) has developed a unique field-deployable droplet microfluidic platform, which will form the foundation of the technology.
The Ocean Technology & Engineering group (OTEG) at the National Oceanography Centre, Southampton, have developed non-droplet microfluidic sensors, which have been deployed in the deep ocean to measure various ocean chemical parameters (nitrate, phosphate, pH).  Some generic aspects of this proven technology (e.g. housings, control electronics, etc.) will be adapted into a final device design for droplet-based TA measurements. The student will have design and manufacturing support from the group’s engineers, as well as chemistry support from the chemists, with the goal of developing a field-deployable sensor, which will undergo initial field trials by the end of the project.
The INSPIRE DTP programme provides comprehensive personal and professional development training alongside extensive opportunities for students to expand their multi-disciplinary outlook through interactions with a wide network of academic, research and industrial/policy partners. The student will be registered at the University of Southampton and hosted at UoS and the NOC. Specific training will include:
· the modeling, design, fabrication, and analysis of droplet microfluidic devices,
· engineering best practices,
· best practices in carbonate system chemical analyses,
· handling and preparing chemical reagents,
· data analysis using MATLAB or similar software,
· practical skills in developing and deploying in situ oceanographic sensor technology, and
· research communication skills including writing and publishing papers.
This project is multidisciplinary and we expect that the exact focus and emphasis of the student’s work will be defined by their skillsets and interests within the scope of the project. The supervisors have wide-ranging complementary expertise across all areas of the project and will provide additional support and training in unfamiliar fields.
 R. H. Byrne, “Measuring Ocean Acidification: New Technology for a New Era of Ocean Chemistry,” Environ. Sci. Technol., vol. 48, no. 10, pp. 5352–5360, May 2014.
 A. M. Nightingale, G. W. H. Evans, P. Xu, B. J. Kim, S. Hassan, and X. Niu, “Phased peristaltic micropumping for continuous sampling and hardcoded droplet generation,” Lab Chip, vol. 17, no. 6, pp. 1149–1157, Mar. 2017.
 A. D. Beaton et al., “Lab-on-Chip Measurement of Nitrate and Nitrite for In Situ Analysis of Natural Waters,” Environ. Sci. Technol., vol. 46, no. 17, pp. 9548–9556, Sep. 2012.