[ES_JOBS_NET] Ph.D. opportunity in plant-soil nitrogen cycling at Aarhus University

[Erika Marín-Spiotta]

---------- Forwarded message ----------
From: "Thomas Larsen" <tl at leibniz.uni-kiel.de>
Date: Jan 8, 2014 3:46 AM
Subject: [ISOGEOCHEM] Ph.D. opportunity in plant-soil nitrogen cycling at
Aarhus University
To: <ISOGEOCHEM at list.uvm.edu>
Cc:

Hello everyone,



I would like to announce the following Ph.D position “Is dissolved organic
nitrogen (DON) the key to plant-soil N cycling?” on behalf of my colleague,
Jim Rasmussen from Aarhus University, Denmark. The deadline is Feb. 1,
2014. See
http://talent.au.dk/phd/scienceandtechnology/opencalls/specific-projects/is-dissolved-organic-nitrogen-don-the-key-to-plant-soil-n-cycling/for
further details.



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*Research area and project description:*

Efficient use of nutrients in agricultural systems is essential to meet a
sustainable intensification of the food production. Legumes add nitrogen
(N) to soils via biological N2-fixation which can substitute energy
demanding mineral N fertilizers. Increasing the dependence on N from
legumes requires better knowledge of plant-soil N cycling to sustain crop
production and reduce environmentally harmful losses. A key issue is
turnover of complex organic N forms to simpler organic N forms, where the
flow through the higher molecular weight (Mw) dissolved organic N (DON)
pools have been identified as the key process in the supply of N to plants
from organic N sources. There is however at lack of knowledge of the
mechanisms controlling the fate of DON pools in soil.

The aim the project is to qualify and quantify the role of higher Mw DON in
plant-soil N cycling in cultivated ecosystems. In special focus is to
elucidate the quantitative importance of plant organic N uptake, the role
of different organic N sources on the flow through the DON pools, and
biotic and abiotic factors affecting the availability of N for plant
uptake. This is achieved by experimentation with double-labeling (15N and 13C)
of white clover followed by investigations of the fate and chemical nature
of enriched DON in plant-soil systems by among other compound-specific
isotope analysis. The PhD-study within the project will have a special
focus the specific fate of DON fractions and the biotic drivers for DON
cycling.

Specifically the PhD-fellow is to investigate:
(i) the flow through the DON pools in soil, and
(ii) microbial actors and activity in the treated soils.

Experimentally this is expected to include methods such as DON
fractionation, compound-specific isotope analysis, and investigations of
biomarkers representing active microbial groups. Thus, the PhD-fellow will
be involved in experimental semi-field work, use of stable isotopes, and
analytical chemistry to characterize biomarkers and DON molecules.



*Qualifications and specific competences:*

Applicants to the PhD position must have a relevant Master’s degree (or
graduate in the very near future – documentation for final thesis and date
of examination must be enclosed in the application) or equivalent. The
applicants shall preferably have a background in one or more of the
following topic areas:

- analytical chemistry applied in biological systems,
- environmental chemistry, or
- agronomy/biology with a focus on plant-soil-microbial interactions.

*Place of Employment and Place of Work:*

The place of employment is Aarhus University (AU) and the place of work is
the Department of Agroecology at Research Centre Foulum, Blichers Allé 20,
DK-8830 Tjele, Denmark.

*Contacts:*

Applicants seeking further information are invited to contact: Jim
Rasmussen: jim.rasmussen at agrsci.dk.

###################





--

Thomas Larsen, PhD

Leibniz-Labor, CAU, Max-Eyth-Str. 11-13, 24118 Kiel, Germany. Office:
+49-431-880-3896, Mobile: +49-177-829-3691
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