Status: this preprint has been withdrawn by the authors.
Mercury fluxes, budgets and pools in forest ecosystems of China: A critical review
Jun Zhou,Buyun Du,Zhangwei Wang,Lihai Shang,and Jing Zhou
Abstract. Mercury (Hg) accumulation and retention in forest ecosystems play a key role in global biogeochemical cycling of Hg. Especially in China, forests are suffering highly elevated Hg loads. Numerous studies have been conducted to characterize the fluxes and pools of Hg in the terrestrial forests in China during the past decade, which provide insights into spatial distributions and estimate the Hg mass balance in forests through observations at widely diverse subtropical and temperate locations. In this paper, we present a comprehensive review of the research status of forest Hg in China to characterize the Hg budgets and pools. Averaged total Hg (THg) inputs at remote forests and rural & suburban forests in China are about 2 to 4-fold and 2.5 to 5-fold higher than the observed values in Europe and North America, respectively. The highly elevated THg inputs are mainly derived from the elevated atmospheric Hg concentrations. Additionally, production of litterfall biomass is showed to be an important influential factor raising the high Hg inputs at subtropical forests. Compared to the input, THg outputs from the forest ecosystems are relative small, which results in large amount of Hg resided in the forest soils. The annual THg retentions range from 26.1 to 60.4 µg m−2 at subtropical forests and from 12.4 to 26.2 µg m−2 at temperate forests of China, which are about 3.8- to 7.9-fold and 1.2 to 2.8-fold higher compared to those in North America. Given the large areal coverage, THg retention in forest is appropriately 69 t yr−1 in China and is much high than that in global scale estimated by models. The much higher THg retention has elevated the THg pools in Chinese subtropical forests, which poses a serious threat for large Hg pulses remitted back to the atmosphere and additional ecological risks in the forest. The current study has implication for the role of China forests in the global Hg biogeochemical cycle and the optimization of atmospheric Hg transport and deposition models.
This preprint has been withdrawn.
Received: 24 Aug 2017 – Discussion started: 23 Apr 2018
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Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
National Engineering and Technology Research Center for Red Soil Improvement, Red Soil Ecological Experiment Station, Chinese Academy of Sciences, Yingtan 335211, China
Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
Buyun Du
State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
University of Chinese Academy of Sciences, Beijing 100049, China
Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
University of Chinese Academy of Sciences, Beijing 100049, China
Lihai Shang
State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
Jing Zhou
Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
National Engineering and Technology Research Center for Red Soil Improvement, Red Soil Ecological Experiment Station, Chinese Academy of Sciences, Yingtan 335211, China
The current knowledge concerning mercury budgets and pools of forest in China is reviewed, including THg and MeHg input fluxes by precipitation, throughfall and litterfall, output by runoffs and soil-atmosphere exchange fluxes, Hg storage in soils and biomass, and their risk assessment. The annual THg retentions at forests of China are about 1.2 to 7.9-fold higher compared to those in North America, and THg retention in forest is much high than that in global scale estimated by models.
The current knowledge concerning mercury budgets and pools of forest in China is reviewed,...
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