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The following postdoctoral position is now being advertised. It will involve
the use of labelled 15N, and natural abundance 15N/14N + 18O/16O.
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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.