Measuring carbonate chemistry using state of the art sensors on marine autonomous vehicles

Understanding the temporal and spatial variability in CO2 concentrations and fluxes in the ocean, year-round high spatial resolution measurements are needed[1]. In remote and operationally challenging regions (e.g. Arctic, Antarctic) field campaigns are infrequent and limited to polar summers creating a seasonal bias to available biogeochemical data. Recent advances to autonomous vehicles and carbonate chemistry sensors (pH, TA, DIC, pCO2) provide new opportunities for high resolution in situ measurements in most oceanic environments. These new data will allow for a more complete understanding of the oceanic CO2 cycle and evaluate with more confidence anthropogenic perturbations.

The Ocean Technology and Engineering group (OTEG) at NOC is a world leader in microfluidic based sensor technology for biogeochemical measurements in the ocean [2, 3]. The purpose of this project is to optimize lab-on-a-chip based carbonate chemistry sensors (pH, TA, DIC, pCO2) developed by OTEG for autonomous measurements on a wide range of autonomous vehicles (Autosubs, Gliders, USVs, floats).

The successful candidate will optimize the operation and performance of these devices in the lab, integrate them on the vehicles and deploy them at sea as a part of several funded projects.

These deployments will demonstrate the capability of these new technologies for autonomous high resolution carbonate chemistry measurements and will generate new observational data from parts of the ocean that so far have been under-sampled.

Lab on chip based sensors for the measurement of pH, DIC, TA and pCO2 have been in development at NOC for the last few years. These devices are now at the prototype stage with initial tests taking place in spring/summer 2018. The successful candidate will work as part of a team of scientists and engineers to optimize the performance and operation of these devices for measurements onboard a wide range of autonomous vehicles. Work will include the optimization of the chemical assays and the measurement’s mechanical sequence to achieve optimum sampling frequency, analytical performance and long-term stability. The student will work closely with software engineers to develop data processing scripts and communications between sensors and vehicles, and mechanical engineers for the design and manufacture of the appropriate bracketry. Initially the work will be based in the laboratories and workshops at NOC and local field test sites, but eventually deployments on autonomous vehicles will span from the tropics to the polar oceans as part of several funded projects.

The NEXUSS CDT provides state-of-the-art, highly experiential training in the application and development of cutting-edge Smart and Autonomous Observing Systems for the environmental sciences, alongside comprehensive personal and professional development. There will be extensive opportunities for students to expand their multi-disciplinary outlook through interactions with a wide network of academic, research and industrial / government / policy partners. The student will be registered at University of Southampton, and hosted by the Ocean Technology and Engineering Group at the National Oceanography Centre in Southampton. Specific training will include: the science and metrology of carbon dioxide and the dissolved carbonate system, autonomous systems and their application to carbon observing, instrumentation development, analytical chemistry and sensor engineering.