Greenhouse Gases in River Catchments to Coastal Seas

Approximately 40 % of methane and 60 % of nitrous oxide come from natural sources which include soils, rivers, estuaries and oceans. As greenhouse gases (GHGs) which account for 17 and 6% respectively of radiative forcing, they play a significant role in our changing climate. Inland waters, estuaries and coasts are important players in the global budgets of GHGs, acting as vigorous sources to the atmosphere of methane and nitrous oxide. The strength of these sources though is highly variable, being related to factors which include nutrient loading, oxygen status and residence time in the system which each impact on production and consumption processes. Whilst there has been significant research activity relating to terrestrial, riverine, estuarine and coastal fluxes of these gases, there is a lack of data which accounts for biological processing and which tracks fluxes between river catchment and the coastal ocean.
Aims
The aims of this PhD project are:
1) To further develop methodology for determination of stable isotopes (15N/14N, 18O/16O and 13C/12C) in dissolved nitrous oxide and methane.
2) To determine seasonal and spatial variability in concentrations, stable isotopes and fluxes of dissolved nitrous oxide and methane between the river catchment and coastal waters.
3) To use stable isotopes in the evaluation of GHG source and sink processes.
The student will receive specialist training in the use of state of the art equipment for measuring: nitrous oxide and methane in air and seawater (PML, UEA) and the determination of N2O and CH4 isotopologues (PML, UEA, Sercon). As a CASE project, the student will spend one month annually at Sercon, to develop an automated extraction system for dissolved gases. They will learn good laboratory practice, quality assurance techniques and receive training in health and safety. They will undertake sea survival training and will acquire skills and logistical acumen required for field sampling. He/she will be encouraged to work with a degree of independence which is essential for fieldwork in remote locations. The student will receive generic research and innovation training via ARIES DTP. The student will join an active and dynamic group at PML undertaking novel and topical research into estuarine, coastal and oceanic biogeochemistry. They will interact closely with scientists and other students working on nutrient cycling, GHG production and consumption, air-sea exchange and the cycling of organic carbon.