CE01 - Terre fluide et solide

Global soil erosion and carbon transfers to inland waters during the Anthropocene: A paleolimnological approach – C-ARCHIVES

Soil erosion and carbon transfers to inland waters during the Anthropocene: A paleolimnological approach

Coupling lake sediment archives and numerical models to investigate past variations in soil erosion and carbon exports from land

Objective of the project and main issues

Accelerated soil erosion alters lateral exports of carbon (C) along the land to ocean aquatic continuum (LOAC) that needs to be accounted for closing the global C budget. However, monitoring data do not extend back as far as few decades, limiting our comprehension of the role of soil erosion and its dynamics in the global C budget on centennial timescale. As such, we lack the ability to make predictions about the responses of soil erosion and C transfers to long-term climate and land cover changes. To address this gap, I propose to analyse the spatial and temporal variability of soil erosion and C exports using an unprecedented data collection of near-annual terrigenous and C signatures preserved in sediments from hundreds of lakes around the world. Paleolimnological reconstructions will be integrated to semi-empirical models of erosion constrained for the last 300 years by pollen fossil and climate paleodata in order to quantify the C exports to inland waters. With a new perspective on empirically constrained models of C-exports, the project will advance our understanding of the influence of land use and climate on the C cycle during the Anthropocene.

C-ARCHIVES focus on organic carbon (OC) transfers as it is the first and largest lateral C-flux released to inland waters globally (5). The methodological strategy proposed for this project is characterized by a strong integration of concepts on soil erosion and sediment dynamics, on decadal and centennial scales, with the inclusion of new estimates of C transfers in lake watersheds based on empirical and model approaches.
In C-ARCHIVES, the efforts will concentrate on: 1) 420 lakes sediment archives that will be used to conduct a data-driven assessment of soil and C transfers, to analyse environmental drivers during the last 300 years, and to validate our model approaches before being exported globally; 2) French EDF dams that will be used to calibrate a semi-empirical erosion model; and 3) a subset of 3-4 sediment archives among the 420 lakes that are part of the well-monitored perialpine lakes (c.f. SOERE OLA observatory managed by the CARRTEL si-ola.inra.fr/si_lacs/login.jsf). These 3-4 sites will be used to set-up and test our models strategy and proxies, and to anticipate future developments with biologists at CARRTEL to investigate downstream responses of lake conditions to altered C fluxes
(coordination - lab level). Altogether, the highly contrasting regions of the global scale investigation (i.e., temperate, boreal, tropical) and the contrasting degrees of anthropization (i.e.,
degree of urbanisation, cropland, grass area…) will allow to depict the effects of the climatic context, climate change and of human activities on long-term C transfers along the LOAC.

In progress

NA

In progress

Accelerated soil erosion alters lateral exports of carbon (C) along the land to ocean aquatic continuum (LOAC) that needs to be accounted for closing the global C budget. However, monitoring data do not extend back as far as few decades, limiting our comprehension of the role of soil erosion and its dynamics in the global C budget on centennial timescale. As such, we lack the ability to make predictions about the responses of soil erosion and C transfers to long-term climate and land cover changes. To address this gap, I propose to analyse the spatial and temporal variability of soil erosion and C exports using an unprecedented data collection of near-annual terrigenous and C signatures preserved in sediments from hundreds of lakes around the world. Paleolimnological reconstructions will be integrated to semi-empirical models of erosion constrained for the last 300 years by pollen fossil and climate paleodata in order to quantify the C exports to inland waters. With a new perspective on empirically constrained models of C-exports, the project will advance our understanding of the influence of land use and climate on the C cycle during the Anthropocene.

Project coordination

Jean-Philippe Jenny (Centre Alpin de Recherche sur les Réseaux Trophiques des Ecosystèmes limniques)

The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.

Partner

CARRTEL Centre Alpin de Recherche sur les Réseaux Trophiques des Ecosystèmes limniques

Help of the ANR 253,018 euros
Beginning and duration of the scientific project: December 2020 - 48 Months

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