List members The following postdoctoral position is now being advertised. It will involve the use of labelled 15N, and natural abundance 15N/14N + 18O/16O. ---------------------------------------------------------------------------- ---------------- UNIVERSITY OF NOTTINGHAM (England), School of Life and Environmental Sciences Postdoctoral Ecologist/Environmental Scientist Applications are invited for a postdoctoral research assistant to work on a cross-disciplinary NERC GANE programme project investigating nitrogen dynamics in Arctic terrestrial ecosystems. Applicants should have field experience (not necessarily polar) and a sound biological and chemical background. A Ph.D. in a relevant subject is essential. Further information and applications forms can be obtained from the Personnel Department, The University of Nottingham, University Park, Nottingham NG7 2RD. Informal enquiries to Professor Johanna Laybourn-Parry phone 0115 951 6262, e-mail:[log in to unmask] Summary The high Arctic contains delicate, relatively pristine ecosystems that are increasingly subject to exported aerial pollution, and higher than average climatic temperature change. Together these factors combine to impose considerable potential change to important biogeochemical processes (e.g. the cycling of carbon and nitrogen) and ecosystem dynamics. This project will concentrate on an important event in the annual cycle - the spring snow melt, which initiates the short summer phase of biological activity. During the period of snow fall (approximately September to May) aerial deposition of elements and pollution (e.g. nitrogen) is accumulated in the snow pack. At melt these elements are deposited as a big pulse into ecosystems which are effectively switching on. The prime questions we propose addressing are (I) how important is this event in transferring enhanced N deposition to tundra ecosystems, and how much is lost as run-off to lacustrine and inshore marine environments., (ii) how does this enhanced N affect the carbon cycle (i.e. plant growth, decomposition processes) and (iii) what is the impact on soil N mineralization*immobilization dynamics. We plan to address these questions via a multi-disciplinary approach using a team which includes soils scientists, geochemists, microbial ecologists and an environmental modeller, over two summers at a high Arctic site in Svalbard (78oN). The work will involve quantifying annual nitrogen fluxes, following snow melt in the Arctic using complementary approaches of 15N-labelling the melting snow pack and determining natural isotopic abundance (18O/16O and 15N/14N) in important terrestrial, biological and aquatic components. The emphasis throughout will be to achieve a unique data set using recently-developed and reliable chemical and biological assays. This information will be used to parameterise an N-flux model which will enable us to predict the ecological consequences of defined N-enrichment scenarios. The Principle Investigators are Professor Johanna Laybourn-Parry, Drs Scott Young, Helen West and Neil Crout from the University of Nottingham, Dr Tim Heaton from the British Geological Survey and Mr Paul Poulton from IACR Rothamstead. The project also has a tied postgraduate studentship which will focus on the modelling aspect of the project. The postdoctoral research assistant will be involved in the experimental work in the field at Svalbard and in the laboratory analysis at Nottingham. We are seeking an individual with a sound biological background who has a good grounding in biogeochemistry. He/she should have field experience. While polar experience would be preferable it is not essential.