Name: Emmy Burd

Project Title: Scalar Processes in the Marine N-cycle: How Important are Sub-Oxic Microzones within the Upper Water Column?

Cohort: 2016/17


University of Stirling

SUERC, University of Glasgow



Dr Michael Wyman, University of Stirling

Dr Sabine Matallana–Surget, University of Stirling

Professor Tom Preston, SUERC, East Kilbride

Professor Nick Owens, SAMS, Oban



My PhD project investigates the interactions between the cyanobacterium Trichodesmium, a major marine nitrogen-fixer, and denitrifying bacteria living in association. These associated proteobacteria have been shown to be actively expressing denitrification machinery. Such denitrification in surface waters could represent an important source of losses of fixed nitrogen from oceanic systems, with potential impacts on the oceanic nitrogen budget. This project aims to determine the environmental conditions under which the denitrification machinery is expressed as well as follow the production and consumption of N2 and nitrous oxides in this system. This will provide new information on nitrogen cycling within Trichodesmium colonies. This system needs investigation as if nitrogen newly fixed by Trichodesmium is being quickly denitrified by epibionts this will reduce the N supply throughout the rest of the water column.


  • Characterization of the genome and physiology of the Trichodesmium-associated nitrifier/denitrifier
  • Determine rates of nitrogen cycling within this system using stable isotope methods including 16S RNA/DNA SIP.
  • Trace the flux of nitrogen between Trichodesmium and its epibionts and the atmosphere using 15N stable isotope tracer analysis.
  • Assess the significance of this association for current global nitrogen models.

Publications/Conference talks/Posters:

December 2016 – Poster presentation at University of Stirling’s Winter Symposium for Biological and Environmental Science Department: Burd, E., Matallana-Surget, S., Preston, T., Owens, N. and Wyman, M., 2016. Interactions between a major marine nitrogen-fixing cyanobacterium and its associated bacteria.

Oliver, D. M., Bird, C., Burd, E., & Wyman, M. (2016). Quantitative PCR Profiling of Escherichia coli in Livestock Feces Reveals Increased Population Resilience Relative to Culturable Counts under Temperature Extremes. Environmental Science & Technology 2016 50 (17), 9497-9505.

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