Freeze-thaw effects on sorption/desorption of dissolved organic carbon in wetland soils |
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Authors: | Xiaofei Yu Yuxia Zhang Hongmei Zhao Xianguo Lu Guoping Wang |
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Institution: | [1]Northeast Institute of Geography and Agroeeology, Chinese Academy of Sciences, Changehun 130012, China [2]Graduate University of the Chinese Academy of Sciences, Beijing 100049, China |
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Abstract: | The effects of freeze-thaw cycles on sorption/desorption of dissolved organic carbon (DOC) in two wetland soils and one reclaimed wetland soil were investigated. DOC concentrations added were 0-600 mg/L. Laboratory in-cubations of sorption/desorption of DOC had been carried out at -15℃ for 10 h, and then at +5℃ for 13 h. Soil sam-ples were refrozen and thawed subsequently for 5 cycles. Initial Mass model was used to describe sorption behavior of DOC. The results indicate that freeze-thaw cycles can significantly increase the sorption capacity of DOC and reduce the desorption capacity of DOC in the three soils. The freeze-thaw effects on desorption of DOC in soils increase with the increasing freeze-thaw cycles. The conversion of natural wetlands to soybean farmland can decrease the sorption capacity and increase the desorption capacity of DOC in soils. Global wanning and reclamation may increase DOC re-lease, and subsequently increase the loss of carbon and the emission of greenhouse gas. |
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Keywords: | DOC sorption desorption freeze-thaw wetland soils |
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