Soil phosphine: the missing link in the global phosphorus cycle

The phosphorus cycle is arguably the most important elemental cycle in natural and agricultural systems, yet still there are many gaps in our knowledge of it, not least the role of transient, gaseous forms of phosphorus such as phosphine. Tantalising evidence exists suggesting it is an important transformation pathway in soils and other substrates. Working with both academic experts and the research team at Elemental Digest Systems Ltd. (EDS), this project provides a unique opportunity to investigate this enigmatic topic, exploring a range of natural soil systems and sources of phosphorus (including EDS's own fertiliser).
Phosphine has now been discovered in many environments including marshes, landfill sites, soil, animal manure and industrial waste and has been identified as a trace component of the earth's atmosphere, providing an exciting facet of phosphorus cycling in soils that can form the basis of some excellent training and investigation for a soil science PhD. Recent studies by Pasek et al. (2014, PNAS) and Kamat et al. (2013, Nature) have now shown that reduced forms of phosphorus, including gaseous phosphine, are closely linked to methanogenesis and more abundant in the environment than previously thought. This PhD training could help to revolutionise our understanding of phosphorus cycling in soils and develop our knowledge on the global (including atmospheric) phosphorus cycle.
The driving objectives of this project will be to provide insight to this most fundamental of soil topics by:
1) Conducting inductive lab experiments to test the hypothesis that: the methods of biological phosphine formation are dominant over chemical mechanisms.
2) Quantifying the significance of phosphine gas production in a range of soils to determine whether or not it represents a significant transformation pathway.
3) Using data from 1 and 2 to revise our conceptual model of the soil phosphorus cycle, with an additional quantitative estimate of the role of phosphine formation in soils and the underlying controlling mechanisms.
Gaining expertise in a range of specialist and fundamental analytical techniques, this project will deliver an experienced all-round soil scientist, with opportunities to develop overseas collaborations in the process. An enquiring mind and a desire to make a difference are required to undertake this exciting delve into the phosphorus cycle, with potentially globally significant results.
The PhD will be based at Rothamsted Research, North Wyke, Okehampton Devon, with University registration at Lancaster University. Supervisors will include Dr Martin Blackwell (Rothamsted) and Professor Phil Haygarth (Lancaster).