Dear colleagues,
Please find below a PhD opportunity about the role of meiofauna in the
functioning of coastal food webs. Work will have to be carried out at
the University of La Rochelle (UMR LIENSs) in France and at the Alfred
Wegener Insititut (Wadden Sea Station Sylt) in Germany.
Do not hesitate to contact me ([email protected]) if any
further question.
Best regards,
Benoit Lebreton
*_Title of the project_*
*Role of meiofauna in the functioning of soft-bottom coastal food webs:
Determination of relationships between properties of food resources and
the structure and functional diversity of meiofauna assemblages.*
*_Hosting institutions_*
**
- UMR Littoral, Environment et Societies (CNRS – University of La
Rochelle), France
- Alfred Wegener Institute for Polar and Marine Research – Wadden Sea
Station Sylt, Christian Albrechts University of Kiel, Germany
- UMR 8222 Laboratoire d’Ecogéochimie des Environnements Benthiques
(LECOB), Sorbonne Universités, UPMC Univ Paris 06, Observatoire
Océanologique, F-66650, Banyuls/mer, France
*_
_*
*_PhD advisors_*
*_
_*
*Dr. Benoit Lebreton (Main supervisor, 60%) *(UMR LIENSs, University of
La Rochelle): Associate professor.
**
*PD Dr. Harald Asmus (40%) *(Alfred Wegener Institute for Polar and
Marine Research – Wadden Sea Station Sylt, Christian Albrechts
University of Kiel, Allemagne) : Researcher
*The salary of this PhD position is funded (100%) by the University of
La Rochelle. It will be a co-supervised position between the University
of La Rochelle, France and the Christian Albrechts University of Kiel,
Germany. This PhD project will be realized in the frame of a European
label.*
*_Project_*
*Background*
Research carried out on the functioning of intertidal mudflats during
the last 20 years demonstrated the high production of these habitats,
mostly due to the very high productivity of benthic microalgae. As a
result mudflats provide numerous ecosystem services, like nurseries and
feeding grounds for fish and shore birds. Functional typology of benthic
microalgae is closely related to sediment grain size, promoting the
dominance of epipelic (i.e. motile) diatoms on muddy sediments whereas
epipsammic (i.e. non motile) diatoms mostly occur in sandy habitats.
Both microalgal groups represent the trophic base of macro- and
microconsumers and among the latter, meiofauna play a role that is
poorly understood. Meiobenthos create a food web of its own including
primary consumers as well as predators, but is connected to the food web
of macroconsumers especially via consumption by small benthic fish and
predatory invertebrates.
In the context of the evolution of coastal areas, in relation with
anthropogenic activities and global change, geomorphology of coasts is
changing. For example, oyster farming activities increase quantity of
fine sediment close to oyster farming areas in the Marennes-Oléron bay.
In the bay of Sylt-Rømø, sand bank movements due to tidal currents
change the morphology of the Bay, and particularly reduce seagrass beds
and mudflat areas. Geomorphological changes of coastal embayments thus
affect the structure of benthic algae assemblages, which very probably
affect the functioning of coastal food webs, and ecosystem services
provided by these habitats.
**
*Aims of the project *
The general aim of this PhD thesis will be to determine how changes of
food source properties affect fluxes of organic matter in soft bottom
coastal habitats. A particular attention will be paid to trophic
relationships between food sources (i. e., benthic diatoms, detrital
matter…) and the meiobenthic consumers.
Different bays and habitats, fueled by very different food resources,
will be compared. Two bays will be studied: the Marennes-Oléron Bay,
dominated by mudflats, and the Sylt-Rømø Bay, mostly dominated by
sandflats. Studied habitats will be mudflats (dominated by epipelic
microalgae), sandflats (dominated by epipsammic microalgae) and seagrass
beds, characterized by a mixture of epipelic and epipsammic microalgae
and high quantities of detrital organic matter).
Many studies have been carried out on the functioning of these two
coastal ecosystems. As a result, food web models of the Marennes-Oléron
and the Sylt-Rømø Bay have already been built, mostly based on
relationships between food resources and macrofauna. Results obtained
during this PhD will be included into preexisting models; to improve the
knowledge about the role of meiofauna in soft-bottom ecosystems.
Finally, this will allow determining what are gains or loss of ecosystem
services provided by meiofauna when sediment grain size is changing.
This project will be built following three steps:
1. Determination of the composition of meiofaunal assemblages in the
different habitats (collaboration with the laboratory UMR 8222 – LECOB,
through a 4-6 months student training or through a scientific stay of
the PhD student at LECOB, under the supervision of J. Rzeznik-Orignac).
A particular attention will be paid to nematodes and copepods, which are
dominant in coastal ecosystems and which present different trophic
types. This step will allow comparing the trophic assemblage of
consumers with the properties of food resources (availability, quality,
quantity).
2. Determination of food sources used by meiofaunal organisms.
Combination of different trophic markers (stable isotopes, fatty acids)
will be used to determine fluxes of organic matter for groups (i. e.
nematodes, copepods) and for feeding types. Fluxes of organic matter
will be estimated thanks to mixing models. Stable isotope signatures of
food sources from the sediment, which are particularly complex to
define, will be computed through determination of the stable isotope
signature of particular fatty acids, markers of these different food
sources.
3. Inclusion of the new data into preexisting models about
Marennes-Oléron and Sylt-Rømø Bay. Methods for the inclusion of data
from stable isotope and fatty acid analyses have already been developed.
The aim of this step will be to complete the existing theoretical models
thanks to the new data and the new methods already developed.
*_General skills and experience_*
The candidate should have a completed postgraduate degree (Master,
Diploma) in Biology, Ecology (especially Marine Ecology) or
Environmental Science. The candidate has to be interested in food webs
and should have a broad background in ecology. His theoretical skills
should include interest in ecology, mathematics and modelling.
Experience in trophic markers in food webs (i.e., stable isotopes, fatty
acids) and/or in static models (ECOPATH, ENA (Ecological network
analysis), inverse analysis) will be welcome. Also practical experience
in coastal research will be helpful. Samplings will have to be carried,
so the selected candidate will have to be autonomous for the samplings
in the field. Because this project is based on a partnership between
France and Germany, very good skills in English are needed for the
realization of this project. Skills in French or in German are a plus,
but are not mandatory.
*_Realization of the PhD project in the frame of the co-supervision and
of the European label_*
The PhD student will work at both locations, i.e. the UMR LIENSs (La
Rochelle, France) and the Wadden Sea Station Sylt (List auf Sylt,
Germany), for several months per year, in order to carry out samplings
and to benefit from the co-supervision.
Application (i.e., cover letter, curriculum vitae with list of
publications when relevant) has to be sent before June 15^th , 2015 at
[email protected] <mailto:[email protected]>et
[email protected].
*_
_*
--
Benoit LEBRETON, PhD
Associate professor
Tel : + 33 (0)5 16 49 67 31
Email : [email protected]
Web page: http://lienss.univ-larochelle.fr/Lebreton-Benoit-MCF-english
UMR Littoral, Environnement et Sociétés
CNRS - Université de La Rochelle
Institut du littoral et de l'environnement
2 rue Olympe de Gouges
17000 La Rochelle
France
http://lienss.univ-larochelle.fr
