Quantifying biogeochemical links between land and ocean: closing a major gap in the global carbon cycle

Location: National Oceanography Centre, Southampton.

Lead supervisor: Daniel J Mayor (National Oceanography Centre, NOC)

Co-supervisors: Chris Evans (Centre for Ecology and Hydrology, CEH), Barry Thornton (James Hutton Institute, JHI), Barry Rawlins (British Geological Survey, BGS), Jasmin Godbold (University of Southampton, UoS)


Rationale

Each year a significant fraction of all the carbon taken up by terrestrial ecosystems is exported to fluvial systems as dissolved and particulate organic matter; approximately 1 Mt of organic carbon is exported annually from the UK landmass alone. Only a fraction of this is thought to reach the open ocean, but our understanding of where, how and when organic matter is lost along the land-ocean continuum remains incomplete. This hampers our ability to understand how changing land management strategies and climate change will influence the fate of terrigenous organic matter and hence global biogeochemical cycles. We seek a highly motivated student that is interested in studying biogeochemical cycling along the land-ocean continuum, an exciting and emerging area of research. This project will combine novel incubation experiments and state-of-the-art stable isotope techniques to quantify the biological removal of terrigenous organic matter in contrasting locations, from headwater streams to coastal seas, at different times of the year. It will also investigate how an increase in the export of bioavailable dissolved organic matter influences the fate of biological unreactive carbon, so-called “priming effects”. The outcome of this project will help inform Earth System Models and the development of future IPCC assessments.

Methodology

This project will involve intensive, seasonal field work in association with CEH and BGS on the rivers Thurso (Scotland) and Conwy (Wales) and their associated estuaries. Additional experimentation and sample collection will take place on a research cruise around the UK landmass in 2018. Respiration measurements made with microsensor technologies will be used to quantify CO2 production rates along the land-ocean continuum. Isotopic analysis of CO2 will be used to provide insight into the source of the respired carbon in freshwater, estuarine and marine settings, exploiting the known isotopic differences between terrestrial and aquatically-derived organic matter. Complementary isotopic analysis of specific biomarker compounds will be used to provide insight into the organisms responsible for processing organic matter. Additional 13C ‘pulse-chase’ experiments will be conducted to examine if and how the addition of labile organic substrates influences the fate of biologically refractory organic carbon in freshwater, estuarine and marine environments. There is further potential for the student to develop the study, particularly with regards to the application of molecular techniques.

Training

The SPITFIRE DTP program provides comprehensive personal and professional development training alongside extensive opportunities for students to expand their multi-disciplinary outlook through interactions with a wide network of academic, research and industrial/policy partners. The student will be registered at the University of Southampton and hosted at the National Oceanography Centre, in the Ocean Biogeochemistry and Ecosystems group. The Ocean Biogeochemistry and Ecosystems group is renowned globally as one of the leading centres of excellence in biological carbon research with plankton ecologists, numerical modellers, remote sensing specialists, theoreticians and particle flux geochemists working together to address the most significant problems in biological oceanography. Additional expertise in microrespirometry and stable isotope techniques will be provided through collaboration with academics at CEH, BGS and JHI. Specific training will include: experimental design, field techniques, bulk elemental and compound-specific stable isotope and fatty acid analyses, data synthesis and statistical analysis, organic geochemical/ molecular analyses.

How to apply

Details on the application process can be found at: http://www.spitfire.ac.uk/how-apply

General admission queries should be addressed to the admission team at [Email Address Removed]

Contact Daniel Mayor [Email Address Removed] for further details about the project.

Closing date: 02/01/2017. Interviews are expected to take place in late February 2017.