O01_03

Soil dynamics revealed by cosmogenic nuclides

HATTÉ C^1,2, CORNU S³

¹Laboratoire des Sciences du Climat et de l'Environnement, Gif-sur-Yvette, France, ²Silesian University of Technology, Gliwice, Poland, ³CEREGE, Aix-en-Provence, France

Over the last few years, considerable attention has been devoted in the scientific literature and in the media to the concept of “ecosystem” services of soils. The monetary valuation of these services is often depicted as a necessary condition for the preservation of the natural capital that soils represent. Amongst the eleven recognized services of soil, at least eight are associated to soil carbon dynamics and to particles displacement: carbon sequestration, climate regulation, provision of food, nutrient cycling, habitat for organisms, flood regulation and foundation for human infrastructure.

Assessing the capacity of soils to provide these services is an immediate societal priority. Conventional solutions such as measuring carbon content, bulk density, particle size distribution... don’t always allow to reach the dynamics notion and/or to answer questions quickly enough for a process reversal to take place. As an alternative method, measuring cosmogenic nuclides can be used to determine the timing of events and the dynamics of major pedological processes. They can provide clues to soil carbon dynamics and particle movement within the profiles themselves. Their use is thus beyond determining rates of erosion, denudation and uplift by analyzing the upper layers of soil profiles as typically done with such isotopes.

In this presentation, we will outline key elements delivered by cosmogenic nuclides to the soil sciences. They have been used alone or in combination with others isotopes. ¹⁴C, ¹⁰Be, ¹³⁷Cs, ²¹⁰Pb will be discussed for the modeling of carbon dynamics in soils and for the transfer of fine particles in profiles.