Know more

Our use of cookies

Cookies are a set of data stored on a user’s device when the user browses a web site. The data is in a file containing an ID number, the name of the server which deposited it and, in some cases, an expiry date. We use cookies to record information about your visit, language of preference, and other parameters on the site in order to optimise your next visit and make the site even more useful to you.

To improve your experience, we use cookies to store certain browsing information and provide secure navigation, and to collect statistics with a view to improve the site’s features. For a complete list of the cookies we use, download “Ghostery”, a free plug-in for browsers which can detect, and, in some cases, block cookies.

Ghostery is available here for free:

You can also visit the CNIL web site for instructions on how to configure your browser to manage cookie storage on your device.

In the case of third-party advertising cookies, you can also visit the following site:, offered by digital advertising professionals within the European Digital Advertising Alliance (EDAA). From the site, you can deny or accept the cookies used by advertising professionals who are members.

It is also possible to block certain third-party cookies directly via publishers:

Cookie type

Means of blocking

Analytical and performance cookies

Google Analytics

Targeted advertising cookies


The following types of cookies may be used on our websites:

Mandatory cookies

Functional cookies

Social media and advertising cookies

These cookies are needed to ensure the proper functioning of the site and cannot be disabled. They help ensure a secure connection and the basic availability of our website.

These cookies allow us to analyse site use in order to measure and optimise performance. They allow us to store your sign-in information and display the different components of our website in a more coherent way.

These cookies are used by advertising agencies such as Google and by social media sites such as LinkedIn and Facebook. Among other things, they allow pages to be shared on social media, the posting of comments, and the publication (on our site or elsewhere) of ads that reflect your centres of interest.

Our EZPublish content management system (CMS) uses CAS and PHP session cookies and the New Relic cookie for monitoring purposes (IP, response times).

These cookies are deleted at the end of the browsing session (when you log off or close your browser window)

Our EZPublish content management system (CMS) uses the XiTi cookie to measure traffic. Our service provider is AT Internet. This company stores data (IPs, date and time of access, length of the visit and pages viewed) for six months.

Our EZPublish content management system (CMS) does not use this type of cookie.

For more information about the cookies we use, contact INRA’s Data Protection Officer by email at or by post at:

24, chemin de Borde Rouge –Auzeville – CS52627
31326 Castanet Tolosan CEDEX - France

Dernière mise à jour : Mai 2018

Menu Logo Principal ANR logo of NSFC mistea niglas leesu iEES LEMON LBE



The project ANSWER in a few words

ANSWER is a French-Chinese collaborative project which focuses on the modelling and the simulation of eutrophic lake ecosystems to study the impact of anthropogenic environmental changes on the proliferation of cyanobacteria.

Worldwide the current environmental situation is preoccupying: the water needs for humans increase while the quality of the available resources is deteriorating due to pollution of various kinds and to hydric stress. In particular, the eutrophication of lentic ecosystems due to excessive inputs of nutrients (phosphorus and nitrogen) has become a major problem because it promotes cyanobacteria blooms, which disrupt the functioning and the uses of the ecosystems.

For 40 years, some measures of reduction of nutrient inputs, especially of phosphorus, have been applied in developed countries to fight against these blooms whereas a reverse tendency of increase of the nutrient loading is observed in other countries. At the same time, the temperature and the atmospheric CO2 concentration have been increasing with significant consequences on the dynamics of phytoplankton communities in lakes. All these local and global changes finally lead to significant modifications of the C/N/P ratio in ecosystems (i.e. the modification of the availability of the three major elements: C, N & P). The project ANSWER will evaluate the consequences that these variations can have on the dynamics of cyanobacterial blooms, by using modelling approaches and numerical simulations which will be based on existing and specific experiments and field data.

To represent the complexity of the functioning of lentic ecosystems, the use of 3D dynamical models, obtained by coupling hydrodynamic and ecological models, is essential. Because the development, the calibration and the simulation of such models require a wide range of skills, researchers of various fields (computer science, applied mathematics, modelling, physical limnology and microbial ecology) will work together to develop an integrative platform for lake ecosystems modelling, which will include tools of data management and knowledge representation, models and statistical methods for model calibration and validation. The models will be used for:

  1. the simulation of the short-term (weeks) impact of sudden changes of C/N/P ratio (due to weather events) on the initiation of blooms and the evolution of their spatial distribution;
  2. comparative simulations of the dynamics and the composition of phytoplankton communities during an annual cycle following the observed trends for the C/N/P ratio in France and in China;
  3. the test and optimization of control strategies whose combined impact with climate changes results in a modification of the C/N/P ratio.

The processes of recycling of organic matter by bacteria in the water column and of release of nutrients from the sediments will be studied experimentally to improve the model ability. Indeed, although these processes are considered as essential for the dynamics of cyanobacteria, they are often ignored or poorly represented in existing models.

One of the difficulties of the implementation of these modelling approaches often comes from the lack of data, or from their poor quality, which makes the validation and the calibration of the models difficult. Thanks to the diversity of the French and Chinese teams gathered in our consortium, we will have access to a rich database composed of good quality data acquired on diversified ecosystems (the large shallow Lake Taihu in China, the long and deep Villerest reservoir and the small and shallow urban Lake Champs-sur-Marne in France). The broad skills of our consortium, ranging from microbial ecology and limnology to modelling, will allow us to take into account in the construction, the validation and the analysis of the models, all the key processes involved in the ecosystem functioning.