Postdoctoral position: Climate change impacts on riverine nutrient transfer and delivery to coastal sea

The laboratory of excellence L-IPSL of the Institut Pierre-Simon Laplace offers a 18-months post-doctoral position to work on the impact of climate change on river-coastal area continuum.


Ecological functioning of aquatic ecosystems is directly impacted by increasing human activities and climate changes. Altering these functions sometimes results in environmental damages affecting the whole aquatic continuum from headwaters to coastal sea (such as eutrophication, green tides, anoxia, fish mortality …).

While regional prospective analysis are still greatly supported by statistical approaches, the newly developed biogeochemical model pyNuts, rises up the challenge of a mechanistic representation of microscopic processes operating in the aquatic continuum, scalable and compatible with regional (and up to continental) domains. PyNuts modeling framework (which include the biogeochemical RIVE model) is now operational for all the north-east Atlantic rivers (more than 350 000 km of drainage network) for assessing present nutrient transfer, including the two past decades.

The proposed research aims at further developing the model to be used in climate change impact studies. Two regional domains will be studied, namely: the Seine-Normandy river basins flowing into the Bay of Seine, and the Adour-Garonne systems associated with small Cantabrian rivers flowing into the Bay of Biscay.

This work will benefit from the recent developments brought to the pyNuts modeling framework, nevertheless, it requires substantial improvements to enable the analysis of climate change impacts: (i) implementation of a hydrological module, (ii) regionalization of several model’s parameters under changing climatic conditions, (iii) selection of relevant ecological indicators using existing estuarine model to assess the impacts of climate change on estuary and costal area biogeochemical functioning.

Description of work

The first task is to add a hydrological module to the pyNuts modeling framework. Priority will be given to simple model structures like GR4J, as it only requires few parameters to be defined and show reasonable performances (compared to more complex and physically based models). Such an implementation also implies the use of downscaling methods to retrieve the climatic inputs (rainfall, temperature) at a finer space-scale than climate models projections (Euro-Cordex database).

In a second step the pyNuts model will be used to assess the quality of water resources forced by changing hydrologic conditions (change in seasonality, prolongation of low flow periods, extreme events …), and will incorporate the impacts of climate change on the biogeochemical functioning of river systems (response of biological processes to higher temperatures, e.g. development of bacterial, phytoplankton and zooplankton biomass, taken into account in the RIVE model). A prerequisite to the use of the pyNuts will be the identification of parameters potentially affected by a change of climatic conditions.

Finally, impact of climate change will be evaluated at the scale of coastal area. Riverine export fluxes from all major river systems associated with smaller coastal rivers will be analyzed. Existing estuarine model will be used to assess changes in N, P, Si, C fluxes along the salinity gradients, and to quantify deliveries to coastal area. Ecological indicator (like the existing ICEP: Indicator of coastal eutrophication potential or other indicator to be developed) will be used to point out eutrophication by nutrients and possible harmful algal blooms, hypoxia events and water acidification.

Expected skills (Young Ph-D graduate accepted)

 PhD in environmental sciences, hydrology or biogeochemistry

 Background in environment modelling (either in hydrology or in biogeochemistry )

 Computing skill, ideally Python

 Background in statistics and data processing

 Ability to work both independently and in collaboration

 Scientific writing skills for publication in scientific journals

Supervision team

This study will strengthen the collaboration required between modeling of nutrient transfers in a context of climate change (METIS ex-Sisyphe teams), and analyzing the potential effect of these “impacted” riverine deliveries to coastal area (LSCE teams).

The work will be conducted under the main supervision of Vincent Thieu from METIS and Christophe Rabouille from LSCE together with expert colleagues from the two teams, namely Ludovic Oudin (hydrology), Josette Garnier (biogeochemistry). The work will be performed in both labs METIS and LSCE according to a schedule collectively defined. Discussions by a larger L-IPSL team will be also organized.

Duration and salary

The post-doctorate will be recruited for 18 months with a net monthly salary around 2000 euros, commensurate with experience. This includes social services and health insurance.

Contact for application

Applications should include a vita, a statement of research interests and the names of at least two references including e-mail addresses and telephone numbers. Applications should be submitted by e-mail to Vincent Thieu, METIS ( and Christophe Rabouille, LSCE (

More information:


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