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Effects of radionuclide contamination on leaf litter decomposition in the Chernobyl exclusion zone

Bonzom, Jean-Marc and Hättenschwiler, Stephan and Lecomte-Pradines, Catherine and Chauvet, Eric and Gaschak, Sergey and Beaugelin-Seiller, Karine and Della-Vedova, Claire and Dubourg, Nicolas and Maksimenko, Andrey and Garnier-Laplace, Jacqueline and Adam-Guillermin, Christelle Effects of radionuclide contamination on leaf litter decomposition in the Chernobyl exclusion zone. (2016) Science of the Total Environment, 562. 596-603. ISSN 0048-9697

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Official URL: http://dx.doi.org/10.1016/j.scitotenv.2016.04.006

Abstract

The effects of radioactive contamination on ecosystem processes such as litter decomposition remain largely un- known. Because radionuclides accumulated in soil and plant biomass can be harmful for organisms, the function- ing of ecosystems may be altered by radioactive contamination. Here, we tested the hypothesis that decomposition is impaired by increasing levels of radioactivity in the environment by exposing uncontaminated leaf litter from silver birch and black alder at (i) eleven distant forest sites differing in ambient radiation levels (0.22–15 μGy h−1) and (ii) along a short distance gradient of radioactive contamination (1.2–29 μGy h−1) within a single forest in the Chernobyl exclusion zone. In addition to measuring ambient external dose rates, we estimat- ed the average total dose rates (ATDRs) absorbed by decomposers for an accurate estimate of dose-induced eco- logical consequences of radioactive pollution. Taking into account potential confounding factors (soil pH, moisture, texture, and organic carbon content), the results from the eleven distant forest sites, and from the single forest, showed increased litter mass loss with increasing ATDRs from 0.3 to 150 μGy h−1. This unexpected result may be due to (i) overcompensation of decomposer organisms exposed to radionuclides leading to a higher decomposer abundance (hormetic effect), and/or (ii) from preferred feeding by decomposers on the un- contaminated leaf litter used for our experiment compared to locally produced, contaminated leaf litter. Our data indicate that radio-contamination of forest ecosystems over more than two decades does not necessarily have detrimental effects on organic matter decay. However, further studies are needed to unravel the underlying mechanisms of the results reported here, in order to draw firmer conclusions on how radio-contamination affects decomposition and associated ecosystem processes.

Item Type:Article
Additional Information:Thanks to Elsevier editor. The definitive version is available at http://www.sciencedirect.com The original PDF of the article can be found at Science of The Total Environment website : http://www.sciencedirect.com/science/article/pii/S0048969716306866
HAL Id:hal-01346001
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:French research institutions > Centre National de la Recherche Scientifique - CNRS (FRANCE)
Université de Toulouse > Institut National Polytechnique de Toulouse - INPT (FRANCE)
French research institutions > Institut National de la Recherche Agronomique - INRA (FRANCE)
French research institutions > Institut de Radioprotection et de Sûreté Nucléaire - IRSN (FRANCE)
French research institutions > Institut de Recherche pour le Développement - IRD (FRANCE)
Other partners > Montpellier SupAgro (FRANCE)
Université de Toulouse > Université Toulouse III - Paul Sabatier - UPS (FRANCE)
Other partners > Chornobyl Center for Nuclear Safety, Radioactive Waste and Radioecology (UKRAINE)
Other partners > Ecole Pratique des Hautes Etudes - EPHE (FRANCE)
Other partners > Université de Montpellier 3 (FRANCE)
Laboratory name:
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Deposited By: Eric Chauvet
Deposited On:22 Jun 2016 13:10

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