Research Task 10 Development of nM nutrient sensors for the marine environment
PhD position. Supervisors: Prof. Eric Achterberg, Dr Matt Mowlem and Malcolm Woodward. Host: SOTON, NOC and PML with secondments to CTG.
Over much of the world’s surface oceans (ca. 40%), nutrient concentrations are depleted to levels below the detection limit of conventional analytical techniques. In these highly stratified oligotrophic waters, biological uptake depletes these nutrients to nanomolar concentrations. Recent work has shown that NO3 is limiting phytoplankton communities in the subtropical North Atlantic Ocean, whilst PO4 is co-limiting (with iron) nitrogen fixation.(1) Oligotrophic ocean regions will increase in size as a consequence of global warming and this strengthens the requirement for nanomolar techniques as conventional methods are unable to observe changes in these regions where NO3 and PO4 control primary production. In recent years, a number of techniques have been developed for shipboard nanomolar nutrient analysis, (2,3), with a high sample throughput. The aim of this PhD studentship is to improve and miniaturize technologies for nanomolar NO3 and PO4 analysis in seawater for autonomous deployment. The objectives are (1) Develop an automated flow system for precise, accurate and high-resolution nitrate and phosphate measurements using optical approaches. (2) Integrate nanomolar nutrient system with communication technologies developed in ITN project. (3) Trial and deploy instrumentation on research cruises, buoys (Western Channel Observatory) and ships of opportunity. We will build upon the existing sea-going nanomolar nutrient system currently operating at NOCS and PML.(4,5) The current system will be miniaturized, with improved control and read-out electronics, liquid wave guide technology and fluidic systems. The system will be interfaced to the communication systems developed in the ITN project, WP3 using the Western Channel Observatory buoys of Plymouth. The instrumentation will be trialled and deployed on NOCS research cruises and ships of opportunity (see RT4). Finally the ESR will be given input and guidance on pre production prototyping by CTG.
(1) Mills, M.M., et al., 2004. Nature, 429, 292–294. (2) Woodward, E.M.S., 2002. Eos, Trans. AGU, 83(4): 92. (3)(4) Wensheng Y, et al., 1998. E. S. & T., 32(17): 2646-2649. (5) Zhang, J.Z. and Chi, J., 2002. E. S. & T. 36(5): 1048-1053. Patey, M.D et al., 2008. Trends in Anal. Chem., 27, (2), 169-182.
