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TitreHuman and climate global-scale imprint on sediment transfer during the Holocene
AuteurJenny, J -P; Koirala, S; Gregory-Eaves, I; Francus, P; Niemann, C; Ahrens, B; Brovkin, V; Baud, A; Ojala, A E K; Normandeau, A; Zolitschka, B; Carvalhais, N
SourceProceedings of the National Academy of Sciences of the United States of America 2019 p. 1-5, https://doi.org/10.1073/pnas.1908179116 (Accès ouvert)
Année2019
Séries alt.Ressources naturelles Canada, Contribution externe 20180346
ÉditeurNational Academy of Sciences
Documentpublication en série
Lang.anglais
DOIhttps://doi.org/10.1073/pnas.1908179116
Mediapapier; en ligne; numérique
Formatspdf (Adobe® Reader®); html
ProvinceCanada; Colombie-Britannique; Alberta; Saskatchewan; Manitoba; Ontario; Québec; Nouveau-Brunswick; Nouvelle-Écosse; Île-du-Prince-Édouard; Terre-Neuve-et-Labrador; Territoires du Nord-Ouest; Yukon; Nunavut
SNRC1; 2; 3; 10; 11; 12; 13; 14; 15; 16; 20; 21; 22; 23; 24; 25; 26; 27; 28; 29; 30; 31; 32; 33; 34; 35; 36; 37; 38; 39; 40; 41; 42; 43; 44; 45; 46; 47; 48; 49; 52; 53; 54; 55; 56; 57; 58; 59; 62; 63; 64; 65; 66; 67; 68; 69; 72; 73; 74; 75; 76; 77; 78; 79; 82; 83; 84; 85; 86; 87; 88; 89; 92; 93; 94; 95; 96; 97; 98; 99; 102; 103; 104; 105; 106; 107; 114O; 114P; 115; 116; 117; 120; 340; 560
Lat/Long OENS-180.0000 180.0000 90.0000 -90.0000
SujetsHolocène; climatologie; effets climatiques; paléoclimats; carottes de sediments lacustres; sols; paléosols; érosion; bassins versants; eaux de surface; lacs; dispersion des sédiments; débit de sedimentation; datation radiométrique; datation au radiocarbone; analyses polliniques; modèles; écosystèmes; carbone; changement climatique; couverture du sol; évaluation environnementale; sédiments lacustres; géologie de l'environnement; géologie des dépôts meubles/géomorphologie; pédologie; géochronologie; paléontologie; Nature et environnement
Illustrationslocation maps; histograms; frequency distribution diagrams; tables; plots; time series
Diffusé2019 10 28
Résumé(disponible en anglais seulement)
Accelerated soil erosion has become a pervasive feature on landscapes around the world and is recognized to have substantial implications for land productivity, downstream water quality, and biogeochemical cycles. However, the scarcity of global syntheses that consider long-term processes has limited our understanding of the timing, the amplitude, and the extent of soil erosion over millennial time scales. As such, we lack the ability to make predictions about the responses of soil erosion to long-term climate and land cover changes. Here, we reconstruct sedimentation rates for 632 lakes based on chronologies constrained by 3,980 calibrated 14C ages to assess the relative changes in lake-watershed erosion rates over the last 12,000 y. Estimated soil erosion dynamics were then complemented with land cover reconstructions inferred from 43,669 pollen samples and with climate time series from the Max Planck Institute Earth System Model. Our results show that a significant portion of the Earth surface shifted to human-driven soil erosion rate already 4,000 y ago. In particular, inferred soil erosion rates increased in 35%of the watersheds, and most of these sites showed a decrease in the proportion of arboreal pollen, which would be expected with land clearance. Further analysis revealed that land cover change was the main driver of inferred soil erosion in 70% of all studied watersheds. This study suggests that soil erosion has been altering terrestrial and aquatic ecosystems for millennia, leading to carbon (C) losses that could have ultimately induced feedbacks on the climate system.
Résumé(Résumé en langage clair et simple, non publié)
Nous avons reconstitué les taux de sédimentation de 651 lacs dans le monde afin d'évaluer les changements relatifs des taux d'érosion de leurs bassins versants depuis 12 000 ans (Holocène). Cette synthèse montre que les humains ont un effet sur les taux d'érosion depuis des millénaires, la première période d'accélération mondiale s'étant produite il y a environ 4 000 ans cal BP. D'importantes variations régionales dans le moment de survenue de l'érosion étaient également apparentes. Elles dépendaient de la densité de population humaine, des migrations et des techniques agricoles.
GEOSCAN ID313442