Supervisors: Prof Matt Mowlem, Dr Socratis Loucaides, Dorothee Bakker (UEA), Andy Watson (Exeter)
This project will develop autonomous sensors and integrate them with new robust ocean going autonomous surface vehicles (ASVs) to observe carbon and carbon fluxes in and across the surface ocean. Observing the oceanic uptake of atmospheric CO2 is of critical importance to understanding historic, present and future climate change, with the oceans historically having absorbed ~48% of our fossil fuel emissions. Elevated CO2 concentrations also cause changes in the ocean carbonate system decreasing pH (ocean acidification). The global scientific community currently observes CO2 partial pressure (pCO2) in the surface waters of the world’s oceans (see http://www.socat.info/and http://icos-uk.org/). Together with other data (e.g. from ships and satellites) this enables estimates of the flux (rate of exchange) of CO2 from the atmosphere into the oceans. The majority of existing data come from instruments carried on the merchant vessel fleet. However, there are significant gaps in the data, including in the Southern ocean, Arctic, Indian Ocean, Malayan Archipelago, South Atlantic and South Pacific where there are few suitable shipping routes and /or conditions are challenging for manned systems. The next generation of sensors that this project will develop, and their application on autonomous systems will fill these critical gaps.
This project will develop state of the art of autonomous carbon observing sensors starting with the current best in breed gas phase pCO2 sensors as well as Lab on chip (LOC) and electrochemical sensors for the dissolved carbonate parameters. It will improve and verify the performance and integrate sensor with ASVs and other contextual sensors (such as temperature, wind velocity, salinity).
State of the art surface pCO2 sensors use Infra-Red (IR) spectroscopy to make measurements in the gas phase and can be calibrated with bottled reference gas. To measure pCO2 in water, the water is equilibrated with a carrier gas that is measured in the IR. LOC technology allows reagent based laboratory analytical techniques and metrology reference materials to be used in the environment. The latest generation of electrochemical sensors includes Ion Selective Field Effect Transistors (ISFETs) for pH measurement which are fast (2 second response time), very precise (<0.001 pH) and low-power. This project will compare the performance of state of the art solutions, develop combinations and make developments and adaptations for use on ASVs. Likely developments include improved analytical performance, methods of in field calibration, power and size reduction, and robustness enhancement.
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 Division. 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; metrology of air sea fluxes; autonomous systems, autonomous surface vehicles and their application to carbon observing; instrumentation development; analytical chemistry; and sensor engineering.
Background Reading:
Sabine, C.L., et al., The Oceanic Sink for Anthropogenic CO2. Science, 2004. 305(5682): p. 367-371.
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.
Rerolle, V.M.C., et al., Development of a colorimetric microfluidic pH sensor for autonomous seawater measurements. Analytica Chimica Acta, 2013. 786: p. 124-131.
To apply for this project, use the: apply for a NEXUSS CDT studentship