Bioindicators reveal water quality: Irstea works to support public policy

What do fish, aquatic plants, fresh water invertebrates and microscopic algae have in common? They all act as indicators of the ecological quality of aquatic ecosystems. Developing this type of biological indicator (bioindicators) to evaluate the quality status of bodies of water meets a real need, as confirmed by the implementation of the European Water Framework Directive (EWFD) in 2000. Its aim is to achieve good ecological and chemical status for bodies of water (natural, artificial, subterranean, surface etc.) by 2027 as well as protecting and conserving unspoiled environments. To achieve this, several stages were defined and the EWFD is now entering its second cycle (2016-2021).


Water quality evaluation tools

Aquatic macrophytes and IBMR readings (the Scie at Heugleville, Seine-Maritime. 2013) © Irstea / C. ChauvinSeveral of Irstea’s scientific teams [1] have been working on bioindicators and the concept of community responses to habitat disruptions. In Bordeaux, a team has specialized in the study of relationships between plant populations and stressors in an environment more or less affected by human activity. This research aims to provide tools that contribute to defining the reference condition of the environment and its good ecological status. To achieve this, scientists are working on data acquisition protocols (e.g., sampling) and finalizing rankings and evaluation systems that use floristic readings to indicate variations in certain parameters or the operational status of the ecosystem.

Their result has resulted in the creation of 4 bioindicators [2], including the macrophyte biological index for rivers (IBMR). Developed in the early 2000s and standardized in 2003, the index has since been adapted in order to meet EWFD evaluation criteria. The "macrophytes in rivers" index has now been incorporated into national evaluation regulations for the 2nd cycle of the Directive. It has also been adopted by 8 other European states in an attempt to harmonize methods. Another indicator is the Biological Diatom Index (IBD), finalized at the end of the 1990s and standardized in 2000. This is regularly used to monitor rivers in France. It was renewed in 2007. Scientists have also adapted the "diatom" indicator to the tropical environments of the DOM-TOM regions and are now looking to use these organisms to diagnose toxic or nutritional pollution.


  • Macrophytes: a generic term for all aquatic plants that are visible to the naked eye (reeds, water lilies, filamentous algae, etc.).
  • Diatoms: microscopic algae comprising a single cell protected by an external skeleton called the "frustule."


Standardizing tools: guaranteeing data quality

The tools created as a result of these research programs, run in partnership with the Ministry for the Environment and Onema, have been validated by French standards. Supervisory ministerial decrees on the evaluation and monitoring of bodies of water require the implementation of these standards, which are published by the French National Organization for Standardization (AFNOR). The standards are the result of Irstea hydroecology research, which is highly anticipated by those involved in monitoring activities, and the successful promotion and transfer of this research. The team is now working on a new "diatom" indicator for lakes (unique in France). "The 4 bioindicators for plant populations are now part of standardized (published or in development) sampling and laboratory analysis protocols as well as evaluation and European reporting regulations required by the EWFD," notes Christian Chauvin, senior hydroecology research engineer at the Irstea Bordeaux Center and president of the AFNOR Standardization Commission [3].

Since 2008, Irstea has led this commission as part of its Aquaref [4] activities in order to ensure organized and consistent indicator development, technical standard creation, regulations and conformity with the national “quality” framework (for example, Irstea participates in the debate on the accreditation of laboratories and their approval by the Ministry).

Standardization of methods, both nationally and on a European level (for a common methodological framework), is now an important issue in order to capitalize on these methodological research results and to formalize transfer to users and routine use in monitoring networks.


Public policy support: transferring tools and training to users

Irstea has taken a leadership role in furthering French standardization strategies in this field as part of the Aquaref program, created in 2007 at the instigation of the Ministry for the Environment. "The Ministry’s aim was to have a spokesperson who could encourage cooperation among the various scientific and technical stakeholders involved in supporting public policy to implement EWFD monitoring." The consortium includes 5 organizations: Ineris (coordinator), BRGM, Ifremer, LNE (National Metrology and Testing Laboratory) and Irstea, which leads the "Hydrobiology" section. Reports produced by these 5 research participants are Aquaref-approved and serve as reference documents for activities in France by the Ministry, water agencies and regional environmental, development and housing departments (DREAL), as well as abroad.

Sampling macrophytes and botanical information on Lacanau lake © Irstea / M. CarroueAquaref’s goals include technical training on new protocols for users, organized primarily by ONEMA with the participation of Irstea scientists. This involves explaining the technical principles and implementation of the monitoring protocols along with their various methodological phases to users, consultants, managers and decision-makers. Subjects include sampling and laboratory processing of samples, calculating indicators, using references and class thresholds to evaluate ecological status, practical use of dedicated software, etc. The aim is to collect representative and homogeneous data from over 4,000 surface freshwater monitoring sites across France in order to provide results of adequate and comparable quality for use in evaluations and assessments.

Standardized tools, rolled out by trained users... What about the collected data? Since 2006, Irstea’s teams have built databases for all types of water in order to centralize data collected by the EWFD monitoring networks in accordance with validated protocols. Developed as operational databases for the scientific development of bioindication methods, they have been used to structure the results obtained from the biological monitoring of water, providing a foundation for the implementation of the national systems that are now used to validate, store and make use of this data. "At Irstea Bordeaux, we are now only processing data relating to macrophytes in rivers and lakes, in anticipation of a complete transition to the national system in the near future," specifies Chauvin. "The rest is managed either on the national or catchment level by Onema and water agencies and directed by the Ministry."


From evaluation tools to diagnostic tools: the next phase

The first tools are now in use, but research is ongoing. Since the Directive has been implemented, it is no longer enough to measure water quality; the ecological status of aquatic environments must also be evaluated, a process involving biological (plants, animals, etc.), hydromorphological, chemical and phsyical and chemical (traditional pollutants, medicinal substances, organic micropollutants, etc.) elements. This change of scale must also be applied to indicators: "Until now, we used evaluation indicators: does the body of water have a good ecological status or not? Now, in the 2nd cycle of the EWFD, we have to work with much more precise assessment indicators that can be used to qualify this ecological status: why does it have a poor ecological status? To what degree? What parameters do we need to change for it to return to a good ecological status?” The aim, as always, is to facilitate better management of these bodies of water.

For more information

[1] Teams from the Bordeaux (macrophytes, diatoms and phytoplankton, estuary fish), Lyon (river invertebrates, typology, hydromorphology of rivers), Aix-en-Provence (lake fish and invertebrates, hydromorphology of lakes) and Antony (river fish) centers.

[2] Macrophytes in rivers and lakes, diatoms in rivers, phytoplankton in lakes

[3] AFNOR T95F standardization commission "ecological quality of bodies of water"

[4] Aquaref, the national reference laboratory for monitoring bodies of water, brings together five scientific and technical organizations involved in public policy support to implement the European Water Framework Directive. For more information.