{"id":21261,"date":"2023-10-16T06:26:38","date_gmt":"2023-10-16T04:26:38","guid":{"rendered":"https:\/\/www.cerege.fr\/?p=21261"},"modified":"2023-12-20T10:17:39","modified_gmt":"2023-12-20T09:17:39","slug":"les-tectites-de-cote-divoire-un-tresor-scientifique-en-territoire-aurifere-3","status":"publish","type":"post","link":"https:\/\/www.cerege.fr\/en\/le-chlore-36-un-nouvel-outil-pour-levaluation-de-la-dynamique-du-carbone-des-sols\/","title":{"rendered":"Chlorine 36, a new tool for assessing soil carbon dynamics"},"content":{"rendered":"
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Soil organic carbon is a key component of soil health, because of its role in soil structure and fertility and in mitigating annual anthropogenic CO2<\/sub>Soil organic carbon is one of the largest terrestrial carbon reservoirs that humans can manage.<\/p><\/div>

An important element in assessing a soil's capacity to store carbon is its age, which can be assessed by modelling or experimentally using carbon isotopes. But the results obtained by the different methods are not consistent, and there are even major differences. For example, the well-known carbon-14 dating method gives soil carbon ages that are a factor of 6 to 10 higher than those estimated by modelling and using stable carbon isotopes.<\/p>

A totally independent method is therefore required. We propose an alternative and independent method based on the measurement of the 36<\/sup>Cl in soils. The 36<\/sup>Cl is a radionuclide produced naturally in the atmosphere by cosmic radiation, but it is also man-made by the nuclear industry. Its production increased by three orders of magnitude when nuclear bombs were tested in the 50s and 70s. In soils, some chlorine, including 36<\/sup>Cl, is retained by soil organic matter in the form of organochlorine molecules.<\/p>

We show that the massive arrival of 36<\/sup>Cl in soils during nuclear testing and its storage in soils can be used to assess the age of soil organic carbon. We measured the stocks of 36<\/sup>Cl retained in the different layers of a forest soil sampled at one of the stations of the Observatoire P\u00e9renne de l'Environnement (OPE) workshop site in Meuse\/Haute-Marne. Cl and 36<\/sup>Cl were extracted from the soils using a hydropyrolysis protocol developed at CEREGE. Measurements of Cl and 36<\/sup>These data are compared with the inflows (rain, vegetation) and outflows (drainage) in the region. 36<\/sup>Cl (Figure 1) and can be used to determine the retention time of the 36<\/sup>Cl in the soil. Our results show that this time increases with depth, with durations ranging from 20 years at the surface to 322 years at a depth of 60 cm. These retention times for 36<\/sup>Cl in soils are comparable to the average ages estimated by approaches based on modelling or stable carbon isotopes. This work therefore suggests that the retention time of 36<\/sup>Cl in a soil can be used as an indicator of the age of the soil's organic carbon.<\/p>

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Figure 1: Conceptual model used to estimate the retention time of 36<\/sup>Cl in the soil. The different boxes represent the stocks of 36<\/sup>Cl measured in different soil layers. The arrows represent the fluxes between these different layers. Within each layer, a small fraction of the 36<\/sup>Cl is fixed in the organic matter of the layer. This fraction is estimated at 5 % of the surface flux and decreases exponentially with depth. This decrease in quantities retained is matched by an increase in retention time with depth.<\/p>

Read more<\/strong><\/p>

36<\/sup>Cl, a new tool to assess soil carbon dynamics, Scientific Report, https:\/\/doi.org\/10.1038\/s41598-023-41555-x<\/a><\/p>

C\u00e9cile Grapeloup, Sophie Cornu, Xavier Giraud, Julie Pupier, Aster Team, Valery Guillou, Philippe Ciffroy, Beatriz Lourino Cabana, C\u00e9cile Couegnas, Christine Hatt\u00e9, Lucilla Benedetti<\/p>

Contact<\/strong><\/p>

Sophie Cornu<\/a> and Lucilla Benedetti, <\/a>CEREGE<\/p>

SCIENTIFIC RESULTS CONTINENTAL SURFACES <\/a>Published on 12 October 2023<\/div><\/div>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<\/div>","protected":false},"excerpt":{"rendered":"

Le carbone organique du sol est un \u00e9l\u00e9ment cl\u00e9 de la sant\u00e9 des sols du fait de son r\u00f4le sur leur structure, leur fertilit\u00e9 et sur l\u2019att\u00e9nuation des \u00e9missions anthropiques […]<\/p>\n","protected":false},"author":724,"featured_media":21262,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[19],"tags":[],"class_list":["post-21261","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-archive"],"acf":[],"publishpress_future_action":{"enabled":false,"date":"2026-06-06 12:53:23","action":"change-status","newStatus":"draft","terms":[],"taxonomy":"category","extraData":[]},"publishpress_future_workflow_manual_trigger":{"enabledWorkflows":[]},"_links":{"self":[{"href":"https:\/\/www.cerege.fr\/en\/wp-json\/wp\/v2\/posts\/21261","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.cerege.fr\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.cerege.fr\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.cerege.fr\/en\/wp-json\/wp\/v2\/users\/724"}],"replies":[{"embeddable":true,"href":"https:\/\/www.cerege.fr\/en\/wp-json\/wp\/v2\/comments?post=21261"}],"version-history":[{"count":5,"href":"https:\/\/www.cerege.fr\/en\/wp-json\/wp\/v2\/posts\/21261\/revisions"}],"predecessor-version":[{"id":21410,"href":"https:\/\/www.cerege.fr\/en\/wp-json\/wp\/v2\/posts\/21261\/revisions\/21410"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.cerege.fr\/en\/wp-json\/wp\/v2\/media\/21262"}],"wp:attachment":[{"href":"https:\/\/www.cerege.fr\/en\/wp-json\/wp\/v2\/media?parent=21261"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.cerege.fr\/en\/wp-json\/wp\/v2\/categories?post=21261"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.cerege.fr\/en\/wp-json\/wp\/v2\/tags?post=21261"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}