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Towards a better understanding of global soil carbon fluxes: The role of weathering and soil development
Sebastian Doetterl
ETH Zürich
Thu, Dec. 12th 2019, 11:00-12:00
Bât. 714, P. 1129, LSCE Orme des Merisiers

State-of-the-art Earth System Models (ESMs) predict that terrestrial carbon (C) storage and its trajectory over time are influenced by two major feedbacks: a negative feedback, in which CO2 fertilization and increased plant productivity increases C storage, and a positive feedback, where C is lost from vegetation and soils due to both warming (Todd-Brown et al. 2013; Friend et al. 2014) and soil degradation. However, soil in ESMs is not represented mechanistically, but rather given a mostly budgetary “black box” function. Similarly, to date, no methodological framework is available that accounts for the combined effects of climate, geology and disturbance on soil C dynamics at larger scales. In addition, most of our process understanding of biogeochemical cycling in soils is derived from data-rich temperate regions. This data has limited applicability in low latitudinal (tropics) or high latitudinal (boreal/subpolar) climate zones, where soils have different properties and drastically different development history. Hence, the lack of soil data from these regions introduces large uncertainty in global estimates of the future C cycle. In my talk I will highlight with a few examples how the weathering history of soils can influence and dominate biogeochemical cycles and microbial processing of carbon in soils. I will also discuss some directions where geochemical proxies that are available at the global scale can be useful to model and predict the spatial and temporal patterns of soil carbon storage and turnover.

Contact : Aline Govin
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