The Seine River Basin

International audienceAmong the six hydrographic basins of metropolitan France, the Seine-Normandybasin is the most human-impacted. This territory of 76,000 km2and 17 millionpeople receives the highest anthropogenic pressure, due to its industrial and agri-cultural activities linked to the development of the urban area of Paris, which hasbeen and still is the economic and social heart of France. These pressures havegradually impacted the hydrological, chemical, and ecological functioning of thebasin, leading to a maximum chemical degradation between the 1960s and the1990s.The very poor chemical and ecological status of water bodies in the 1980s led asmall group of researchers to propose a PIREN-Seine, i.e. an interdisciplinaryenvironmental research program created by the French National Centre for Scien-tific Research (CNRS). This program was launched in 1989 in the context ofinsufficient wastewater treatment in the Paris conurbation. Its first achievementconsisted in developing models to better understand the river hydrological andbiogeochemical functioning. These tools have made it possible to bring togetherresearch teams on a common object of study, the whole Seine watershed; theprogram has also been a forum for dialogue between the basin ’ s institutionalpartners and researchers, enabling the latter to make management proposals toestablish investment priorities based on the results of these models.Over the past 30 years, the PIREN-Seine program has grown up, has attractedsocial scientists, and has generated a vast number of disciplinary and interdisci-plinary publications, more than 100 PhD theses, hundreds of publications inscientific journals, and as many communications in international workshops andconferences. Nevertheless, the collective visibility of this group of scientists andinstitutional partners is still relatively low internationally, since most publicationcredits are given to individuals, to their laboratories, or to their research institutions.Moreover, the names of these laboratories and institutions have also evolved over time, making the recognition of this collective effort even more difficult. This bookis the opportunity to present the most salient or recent results of the program,presented here as trajectories that relate environmental changes, societal changes,and the state of the Seine River basin waterbodies, which is nowadays largelycontrolled by the balance between pressures, water and river uses, and socialresponses.The book covers a broad range of topics such as (1) the estimation of fluxestransported from headwaters to the coastal zone, at a very fine spatial scale, usingmodels, (2) long-term analyses (50–200 years) of the socio-ecosystem Seine, usingarchives, retro and prospective modeling, (3) the identification and quantification ofsources and transfer of a wide variety of elements and pollutants (nutrients, carbon,trace metals, POPs, pharmaceuticals, pesticides, microplastics, etc.), (4) the studyof microbial contaminations, and (5) the analysis of the impact of water quality andcontaminations on biota.Studies considering the Seine River basin as a socio-ecological system areincreasingly present within the PIREN-Seine program, which has been includedin the Zone Atelier Seine (ZA Seine). The latter coordinates the research activitieson the Paris city, the Seine River basin, and the Seine River estuary. It is also part ofthe European Long-Term Socio-Economic and Ecosystem Research (LTSER) pro-grams. The large size of the basin and the longue-dure´e approach (up to 200 years)make this territory a rare and fully documented example of the multiple andevolving interrelations between a river, its large basin and their society whichcharacterize the Anthropocene era