Supervisors: Dr Socratis Loucaides (NOC), Prof Matt Mowlem (NOC), Nick Bates (Ocean & Earth Science, UoS)
Understanding the temporal and spatial variability in CO2 concentrations and fluxes in the ocean, year-round high spatial resolution measurements are needed. 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 data will allow for a more complete understanding of the oceanic CO2 cycle and evaluate with more confidence anthropogenic perturbations.
Carbonate chemistry sensors technologies developed at the Ocean Technology and Engineering group (OTEG) at NOC are now reaching maturity with a fast-growing track record of successful deployments. To completely characterize the seawater carbonate system, two of the four carbonate chemistry parameters must be measured simultaneously at high accuracy and precision. The purpose of this PhD project will be to identify the most appropriate analytical assays and technologies and implement them on a single unit fit for integration on autonomous vehicles.
The speciation of the seawater carbonate system can be resolved if only two of the four parameters (pH, TA, DIC, pCO2) are known. Several analytical techniques are currently under development by OTEG for the measurement of all four parameters individually including titrations, spectrophotometry, fluorescence and conductimetric analysis. In some cases, the same technology can be used to measure more than one parameter. For example, pH, TA and DIC can be measured spectrophotometrically with only minor changes to the analytical setup. Similarly fluorescence can be used for measurements of pH and pCO2and conductivity for DIC and TA. The students main goal will be to numerically and experimentally evaluate each technique and identify a design that will lead to a two-in-one sensor system for the characterization of the seawater carbonate system on-board gliders and other autonomous vehicles.
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 the University of Southampton, and hosted at the National Oceanography Centre in the Ocean Technology and Engineering Group. We welcome applicants from a range of numerate scientific and engineering disciplines and expect to do extensive training and up skilling to enable high level achievement in this new and growing area. 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.
Background Reading:
Martz, T.R., et al., TECHNOLOGY FOR OCEAN ACIDIFICATION RESEARCH Needs and Availability. Oceanography, 2015. 28(2): p. 40-47.
Beaton, A.D., et al., Lab-on-Chip Measurement of Nitrate and Nitrite for In Situ Analysis of Natural Waters. Environmental Science & Technology, 2012. 46(17): p. 9548-9556.
Rérolle, V.M.C., et al., Development of a colorimetric microfluidic pH sensor for autonomous seawater measurements. Analytica Chimica Acta, 2013. 786(0): p. 124-131.
To apply for this project, use the: apply for a NEXUSS CDT studentship