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Lakes are essential ecosystems that provide a large number of ecosystem services whose quality is strongly impacted by human pressures. Optimal uses of lakes require adapted management practices which in turn rely on physico-chemical and biological monitoring. Long-term ecological monitoring provides large sets of environmental data. When such data are available, they have to be associated to metadata and to be stored properly to be accessible and useable by the scientific community. We present a data informatics system accessible to anyone who requests it. Maintained online since 2014 (https://si-ola.inrae.fr), it is originated from the Observatory on LAkes (OLA). It contains long-term data from 4 peri-alpine lakes (Lakes Aiguebelette, Annecy, Bourget, Geneva/Léman) and 24 high-altitude lakes of the northern French Alps. We describe the generated long-term data series, the data type, the methodologies and quality control procedures, and the information system where data are made accessible. Data use is allowed under the condition of providing reference to the original source. We show here how such a platform clearly enhances data sharing and scientific collaboration. Various studies referring to these data are regularly published in peer-reviewed journals; providing in fine a better understanding of lakes’ ecosystems functioning under local and global pressures.

Vingt ans après la première conférence de Rio, qu'est devenue la proposition de conduire nos sociétés vers un développement durable ? Adopté par les uns, utilisé comme faire-valoir par les autres, ce concept de développement durable est souvent vidé de son sens. Or, l'impact exponentiel des activités humaines sur les ressources naturelles, la santé des populations et le milieu exige d'expliquer ce qu'il est précisément. Qu'est-ce que le développement durable aujourd'hui ? Qu'en est-il de la disponibilité des ressources et de l'usage que nous en faisons ? Dans le domaine de l'eau, du climat, des sols, de la biodiversité ? En milieu rural, sur le littoral ou encore en milieu urbain, là où la majorité de la population va vivre d'ici 2050, comment consommons-nous au fil du temps, à travers les territoires? Quelles incidences les activités humaines ont-elles sur les ressources, sur la santé des populations et sur le milieu lui-même ? Les relations entre l'humanité et l'environnement doivent-elles évoluer ? Autant de questions posées à des scientifiques qui éclaircissent la complexité des interactions entre les systèmes et proposent des solutions pour un avenir sur le long terme. De nos écosystèmes à nos modes de consommation, des risques naturels aux nouvelles technologies ou aux pollutions, des usines du futur au traitement des déchets, Le développement durable à découvert informe, explique, partage tout ce que la science actuelle est capable d'apporter au défi majeur du XXIe siècle : comment mieux comprendre la complexité des enjeux qui nous concernent tous et assurer le développement de l'humanité sans détruire son biotope. Économistes, physiciens, sociologues, agronomes, écologues... plus de 150 chercheurs se sont mobilisés pour associer leur expertise à leur regard critique et décrire, comprendre, modéliser, imaginer, illustrations et schémas à l'appui, les outils destinés à construire les sociétés équitables de demain.(résumé 4e de couv)

L’ère Anthropocène* – du début de l’ère industrielle à aujourd’hui –, est caractérisée par des tensions entre écosystèmes et sociétés, qui ne cessent de croître. Le changement global en cours inquiète autant par les questions posées par le réchauffement du climat, que par les perturbations des écosystèmes, comme en témoignent les conférences internationales sur le climat ou la promulgation de Directives-cadres pour la restauration des milieux. Ces mesures impliquent une connaissance approfond...

International audience; A study of trace metal (TM) contamination was conducted at Lake Tonga (Algeria), a site surrounded by several indirect contamination point sources such as an abandoned mine and steelworks. Studying two sampling sites over four seasons, we were able to depict the spatial and temporal variability of TM contamination in the lake. Among the seven TM examined (Pb, Cd, Fe, Zn, Ni, Cu, and Cr), only Fe, Pb, and Cd showed concentrations significantly higher than the site's geological background. The contamination index (sediment concentration/background concentration) calculated for these three TM (Cd = 1.9 ± 1.6, Fe = 6.8 ± 1.8, and Pb = 3.3 ± 2.6) clearly indicated anthropogenic contamination. Sediment TM contamination differed both between sampling sites and seasons despite environmental variables (e.g., oxygen and pH) being similar, thus suggesting different TM contamination sources. Fe contamination was high at the two sampling sites and over all studied seasons, possibly indicating general lake-scale Fe contamination, probably related to atmospheric deposition of steelworks emissions both on the lake and within the watershed. Lake tributaries were further suspected of channeling Fe contamination from the watershed into the lake. On the other hand, the sampling site close to the outlet was especially rich in Cd and Pb typically reflecting contamination by mine wastes. The indirect connection between the abandoned mine and the lake indicates that runoff of mine leachates through groundwater was likely a candidate in explaining the specificity of the TM contamination in this part of the lake. This study provides insights for management of TM contamination by addressing both spatial and temporal variability within the lake as well as differences in contamination sources.

Polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) are organic pollutants (OPs) that can originate from both the watershed (i.e. local sources) and long-range emissions. Even when local sources are identified, the propagation of OPs in aquatic systems remains poorly known. The southern part of Lake Bourget (France) is known to be impacted by PAHs and PCBs from local urban sources and surficial sediments exhibit OP concentrations higher than in the North. However, little is known about the propagation of this pollution within the lake. We propose a dual approach to assess the propagation of 13 PAHs and 7 PCBs in 10 littoral sites. The first method quantifies the similarities between the OP profiles of the sites and that of a local urban signature used as a reference of the southern watershed, and the second method is based on concentration ratios. The two independent methods provided convergent results and supported a south–north gradient of the OPs propagation. Southern sediments exhibited the highest OP contents, similarities in profiles with the local signatures, and abundance of heavy molecular weight congeners. PAH contents and profiles seemed to be more variable than for the PCBs. Changes in the littoral OP profiles with tributary distance illustrated the spread from tributary outlets that may act as contamination pathways. Two littoral sites did not match this north–south gradient for PAH contamination, indicating another potential point sources. These results furthermore underline the relevance of focusing on the littoral zone in the prospect of assessing propagation of pollution within a lake.