| Poyang Lake Eco-economic Region is located in the north of Jiangxi province, which is an important ecological functional conservation area and commodity grain base of China. During the process of achieving economic development and environmental protection, atmospheric acid deposition is still an important aspect that constraints the sustainable development of Poyang Lake Eco-economic Region. A number of previous studies are mainly about the relationship between δ34S value of atmospheric precipitation and sulfur source, however, research from the perspective of δ34S values of plants is still rare. On the basis of previous studies, this article takes Nanchang, Jiujiang, Jingdezhen and Fuzhou city within the scope of Poyang Lake Eco-economic Region as the main research areas, and selects rape, wheat and epilithic mosses as the objects of study. By respectively testing the sulfur isotope ratio of epilithic mosses, the seed(grain), stem(straw) and pod(shell) of rape and wheat, this paper analyzed sulfur isotopic composition characteristics of these plants and the relationship with atmospheric sulfur source. Four major conclusions are as follows:1. In the Poyang Lake Eco-economic Region, sulfur contents of rapeseeds are higher than that of rape pods and stems, but the δ34S values of rapeseeds are lower than of pods and stems; sulfur isotopic composition characteristics of wheat is similar to that of rape, showing that the δ34S value of seed(grain) is the lowest.2. All the δ34S values of epilithic mosses in the Poyang Lake Eco-economic Region are positive, and the average is 4.9‰(variation range is 1.9‰ to 9.6‰). Most are distributed between 3.0 ‰ and 7.0 ‰, which are close to the δ34S value of coal in northern China(+3.68 ‰). It shows that the main sulfur source of atmospheric sulfur deposition is caused by coal burning and other human activities; in addition to using local coal, the research areas also use large amounts of coal from northern China; under the influence of atmospheric circulation, long-distance transmission sulfur from the north may be one of the sulfur source of atmospheric sulfur deposition.3. In the Poyang Lake Eco-economic Region, the variation range of the δ34S values of epilithic mosses is close to the δ34S values of its corresponding city’s atmospheric precipitation, showing it can replace the δ34S value of rainwater to reveal the sulfur source of atmospheric acid deposition. On this basis, this article takes the δ34S values of epilithic mosses reflecting atmospheric sulfur environment. By the comparison with soil sulfur environment,it can be seen that δ34S values of epilithic mosses are far below the δ34S values of total sulfur in rape rhizosphere soil, while closer to the δ34S value of soil soluble sulfur, indicating That atmospheric environment is relatively enriched more “light sulfur” while the soil is enriched more heavy sulfur sources, and soluble sulfur in the rhizosphere soil may be mainly derived from atmospheric sulfur deposition.4. In the Poyang Lake Eco-economic Region, the δ34S values of rape tissues is closely related with the concentration of SO2 in the air, and the sulfur isotope ratio of rape in Nanchang City is most affected by acid atmospheric deposition; besides, changes in the δ34S values of wheat tissues have an opposite trend with the interannual variability of SO2 emissions; also, there is a significant negative correlation between the δ34S values of epilithic mosses(x) and SO2 concentration in air(y), namely, y=-82.607x+7.6326,R2=0.85. |
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