Effects of radionuclide contamination on leaf litter decomposition in the Chernobyl exclusion zone
Effects of radionuclide contamination on leaf litter decomposition in the Chernobyl exclusion zone
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DOI：
10.1016/j.scitotenv.2016.04.006
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发表时间：
2016-08-15
影响因子：
9.8
通讯作者：
Adam-Guillermin, Christelle
中科院分区：
文献类型：
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作者：
Bonzom, Jean-Marc;Hattenschwiler, Stephan;Adam-Guillermin, Christelle
放射性污染对凋落物分解等生态系统过程的影响在很大程度上仍然未知。由于土壤和植物生物量中积累的放射性核素对生物体有害，因此放射性污染可能改变生态系统的功能。在这里，我们通过将未受污染的白桦和黑桤木凋落叶暴露在(i) 11个环境辐射水平不同的遥远森林地点（0.22-15 μ Gy h(-1)）和（ii）在切尔诺贝利禁区内的一个森林内沿着放射性污染的短距离梯度（1.2-29 μ Gy h(-1)）来测试分解被环境放射性水平增加所损害的假设。除了测量环境外剂量率外，我们还估计了分解者吸收的平均总剂量率（ATDRs），以准确估计放射性污染剂量引起的生态后果。考虑到潜在的混杂因素（土壤pH、水分、质地和有机碳含量），11个偏远森林站点和单个森林的结果显示，随着ATDRs从0.3到150 mu Gy h（-1）的增加，凋落物质量损失增加。这一意想不到的结果可能是由于(i)暴露于放射性核素的分解者有机体的过度补偿导致了更高的分解者丰度（辐射效应），和/或（ii）与本地生产的受污染的凋落叶相比，我们实验中使用的分解者更喜欢吃未受污染的凋落叶。我们的数据表明，20多年来森林生态系统的放射性污染不一定对有机物腐烂产生有害影响。然而，需要进一步的研究来揭示本文报告的结果的潜在机制，以便就放射性污染如何影响分解和相关生态系统过程得出更确切的结论。(C) 2016 Elsevier B.V.版权所有
The effects of radioactive contamination on ecosystem processes such as litter decomposition remain largely unknown. Because radionuclides accumulated in soil and plant biomass can be harmful for organisms, the functioning 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 mu Gy h(-1)) and (ii) along a short distance gradient of radioactive contamination (1.2-29 mu Gy h(-1)) within a single forest in the Chernobyl exclusion zone. In addition to measuring ambient external dose rates, we estimated the average total dose rates (ATDRs) absorbed by decomposers for an accurate estimate of dose-induced ecological 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 mu Gy 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 uncontaminated 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 drawfirmer conclusions on howradio-contamination affects decomposition and associated ecosystem processes. (C) 2016 Elsevier B.V. All rights reserved.