Bajard, Manon; Etienne, David; Quinsac, Sébastien; Dambrine, Etienne; Sabatier, Pierre; Frossard, Victor; Gaillard, Jérémie; Develle, Anne-Lise; Poulenard, Jérôme; Arnaud, Fabien; Dorioz, Jean-Marcel (2018): Age-depth model, XRF elemental analysis, loss on ignition, grain size, CNP and total P analyses from Lake Benit sediment sequence [dataset publication series]. PANGAEA, https://doi.org/10.1594/PANGAEA.896613,

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Supplement to: Bajard, M et al. (2018): Legacy of early anthropogenic effects on recent lake eutrophication (Lake Bénit, northern French Alps). Anthropocene, 24, 72-87, https://doi.org/10.1016/j.ancene.2018.11.005

Mountain lakes are integrated sentinels of changes in the terrestrial environment, where these changes threaten the quality of the ecosystem services these lakes provide, including high biodiversity, economic and leisure activities. There are few evidentiary records of the long-term relationships between human pressure and its observed impacts. Multiproxy analyses of the Lake Bénit sediment sequence, including dating, grain-size, geochemistry, pollen, non-pollen palynomorphs and chironomid assemblage reconstructions, allowed us reconstructing past environmental evolution and lake trophic changes. Combined with the soil analyses of the catchment, these data provide a record of the relationships between human activities and the lake-catchment ecosystem, and show the effect of inundation of the shore previously used as pasture. From 2100 to 1100 yrs cal. BP, the catchment was forested. During the Middle Ages, the catchment was deforested for grazing, triggering an increase in erosion and a change in sediment sources. The lake remained oligotrophic over most of the last millennia. The trophic state changed abruptly in the 20th century with the intensification and multiplication of tourist activities in the catchment, i.e., fishing, hiking, while pastoral activities decreased. The sudden eutrophication coincides with an artificial increase of the lake water level in AD 1964 to improve fishing activities. A release of phosphorus from the flooded soils was observed, which may be responsible for the current eutrophication. One thousand years of grazing practices would have led to the observed P concentrations in the lake shore soils, transferred by the cattle to this area, which highlights the combined effects of past and recent activities on the current eutrophication process, and the legacy of both soils and early anthropogenic activities.

This data set combines the data from Lake Benit sediment sequence used for the publication of Bajard, M., Etienne, D., Quinsac, S., Dambrine, E., Sabatier, P., Frossard, V., Gaillard, J., Develle, A.-L., Poulenard, J., Arnaud, F., Dorioz, J.-M., 2018. Legacy of early anthropogenic effects on recent lake eutrophication (Lake Bénit, northern French Alps). Anthropocene 24, 72–87. https://doi.org/10.1016/j.ancene.2018.11.005.

The dataset includes Age-depth model, XRF Avaatech core scanner, Loss On Ignition, laser grain-size analyses, Corg, N, POlsen and total P analyses. The sediment sequence is 98 cm and covers the last two millennia.