| PhD Student:
Ranking stresses using food web analysis
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Nijmegen, (Gelderland),
40 hours per week Radboud University Nijmegen
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Job description
Within the framework of the ongoing cooperation
between the Department of Environmental Science (Radboud University, RU-DES)
and the Laboratory for Ecological Risk Assessment (National Institute for
Public Health and the Environment, RIVM-LER), new computational and ecological
methods are developed for the assessment of ecotoxicological risks of exposure
to multiple physical and chemical stressors. RU-DES has currently one vacancy
for a PhD position within the aforementioned framework entitled ‘Ranking
stresses using food-web analysis’. In order to obtain insights into the
relative importance of different kinds of stressors on the occurrence (presence/absence)
and numerical abundance of species, expected species distributions in relation
to the impact of anthropogenic stressors will be obtained by exploring
the structure (topology) of food webs (e.g. Mulder et al. 2005a) and networks
(e.g. Posthuma and De Zwart 2006). This can be achieved in several ways.
To analyse the effects of chemicals, biotic and abiotic monitoring data
will be combined with metabolic functions to describe the toxicokinetics
and toxicodynamics at species level. Toxicity extrapolation (Luttik et
al. 2005) also plays an important role here. Alternatively, stressors may
also be considered to destabilize the system in a more general sense, for
instance by favouring species with certain traits and strategies. Other
human-mediated stressors to be evaluated include macronutrients (total
Kjeldahl nitrogen, phosphorus), micronutrients and trace elements (Cr,
Cu, Ni, Pb and Zn) and pH. Recently we have begun to investigate monitoring
data this way (e.g. Mulder et al. 2003, 2005b). The selection of stressors
will be performed by multiple regressions and generalized linear models.
Patterns and processes predicted by model simulations must be tested by
the available field data (empirical evidence). For example, one model may
explain the extent to which certain stressors will contribute to increasing
occurrence of taxa that better fit the dynamics of a new situation at community
level. Such models will therefore be able to provide a quantitative prediction
of such changes, although we will include all other trends predicted by
these models. Using these approaches it will be possible to select stepwise
the environmental pressure with the highest impact, or the stressor that
can be managed more effectively, giving precious guidelines for action
to policy and environmental managers. 1. Luttik R, Mineau, P, Roelofs,
W (2005) A review of interspecies toxicity extrapolation in birds and mammals
and a proposal for long-term toxicity data Ecotoxicology 14, 817-832 2.
Mulder, C, Aldenberg, T, De Zwart, D, Van Wijnen, HJ, Breure, AM (2005)
Evaluating the impact of pollution on plant-Lepidoptera relationships.
Environmetrics 16, 357-373 3. Mulder, C, Cohen, JE, Setälä, H, Bloem, J,
Breure, AM (2005) Bacterial traits, animals’ body mass and numerical abundance
in the detrital soil food web of Dutch agricultural grasslands. Ecology
Letters 8, 80-90 4. Mulder, C, De Zwart, D, Van Wijnen, HJ, Schouten, AJ,
Breure, AM (2003) Observational and simulated evidence of ecological shifts
within the soil nematode community of agroecosystems under conventional
and organic farming. Functional Ecology 17, 516-525 5. Posthuma, L, De
Zwart, D (2006) Predicted effects of toxicant mixtures are confirmed by
changes in fish species communities in Ohio, USA, rivers. Environmental
Toxicology and Chemistry 25, 1094–1105
Requirements
University Graduate
The candidate should hold an MSc degree in Natural (Environmental) Sciences.
A combined empirical-theoretical expertise on the impact of physical-chemical
stressors on populations and communities is required. Important selection
criteria are: curiosity, commitment, elementary modelling, good communication
skills, good writing skills in English and experience in ecotoxicology
and statistical techniques.
Organization
Radboud University Nijmegen Faculty of
Science
Strategically located in Europe, Radboud
University Nijmegen is one of the leading academic communities in the Netherlands.
A place with a personal touch, where top-flight education and research
take place on a beautiful green campus in modern buildings with state-of-art
facilities.
The Department of Environmental Science
is embedded in the Institute for Water and Wetland Research, Faculty of
Science, Radboud University. Its mission is (1) scientific research on
environmental issues, (2) education at BSc-MSc-PhD levels and (3) service
to society for regional management and national and international policy.
We aim to understand and assess biological responses to combined physical-chemical
pressures. Our efforts concentrate on: - (topics) interactions of multiple
stressors, in particular physical reconstruction and chemical pollution,
with ecosystems and human health - (aim) understanding and predicting -
(geography) rivers and estuaries, in particular the Rhine-Meuse-Scheldt
delta and - (methods) theoretical concepts (models) developed in interaction
with practical cases (laboratory experiments and field surveys) - (results)
monodisciplinary in-depth insight and multidisciplinary overall assessment
For additional information see website. The Laboratory for Ecological Risk
Assessment (LER) of RIVM. The mission of LER is to provide a scientific
basis for the assessment of impacts of different types of environmental
stress on the composition and functioning of ecosystems in their mutual
coherence. The emphasis is on the fate of substances in ecosystems, the
exposure of organisms and the subsequent effects on ecosystems. LER focuses
on developing knowledge of the structure and functioning of ecosystems
and the effect of different types of ecosystem stress thereon, individually
or in combinations. LER enables model development as well as experimental
research. The models derived describe the relationships between environmental
stress and the structure and functioning of ecosystems. These are applied
in the risk assessment methods that are developed and in the decision support
systems for the impacts of environmental stress on ecosystem quality. Results
are applied in environmental policy and management to derive scientifically
sound and effective policy measures. For additional information see website.
Conditions of employment
Maximum salary amount in Euro's a month 2.612
Employment basis: Temporary for specified period
Duration of the contract: 4 years with a go/no go decision after 18 months.
Maximum hours per week: 40
Additional Information
Additional information about the vacancy
can be obtained from:
prof.dr. A.M. Breure
Telephone number: +31-30-2743068
E-mail address: ton.breure <at> rivm.nl,
t.breure <at> science.ru.nl
Or additional information can be obtained through one of the following
links.
Application
You can apply for this job before 31-12-2008
by sending your application to:
Faculteit der Natuurwetenschappen, Wiskunde
en Informatica
Mr. M. Frieling
PO Box 9010, 6500 GL Nijmegen, NL
E-mail address: pz <at> science.ru.nl
When applying for this job always mention
the vacancy number 62.39.08.
The short URL code for this job opening
is: 00345-333.
You can use this as a direct link to the job by adding the code to the
URL www.academictransfer.org/
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