The release of phosphorus from sediment into water in subtropical wetlands: a warming microcosm experiment

Authors

  • Zhang ZhiJian,

    Corresponding author
    1. College of Natural Resource and Environmental Sciences, ZheJiang University, Yuhangtang Avenue 358, HangZhou, ZheJiang Province, 310058, China
    • College of Natural Resource and Environmental Sciences, ZheJiang University, Yuhangtang Avenue 358, HangZhou, ZheJiang Province, 310058, China.
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  • Wang ZhaoDe,

    1. State Key Laboratory of Lake Science and Environment, NanJing Institute of Geography and Limnology, Chinese Academy of Science, NanJing 210008, China
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  • Joseph Holden,

    Corresponding author
    1. water@leeds, School of Geography, University of Leeds, Leeds, LS2 9JT, UK
    • water@leeds, School of Geography, University of Leeds, Leeds, LS2 9JT, UK.
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  • Xu XinHua,

    1. College of Natural Resource and Environmental Sciences, ZheJiang University, Yuhangtang Avenue 358, HangZhou, ZheJiang Province, 310058, China
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  • Wang Hang,

    1. College of Natural Resource and Environmental Sciences, ZheJiang University, Yuhangtang Avenue 358, HangZhou, ZheJiang Province, 310058, China
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  • Ruan JingHua,

    1. College of Natural Resource and Environmental Sciences, ZheJiang University, Yuhangtang Avenue 358, HangZhou, ZheJiang Province, 310058, China
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  • Xu Xin

    1. College of Natural Resource and Environmental Sciences, ZheJiang University, Yuhangtang Avenue 358, HangZhou, ZheJiang Province, 310058, China
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Abstract

Global warming poses a great threat to wetland ecological stability and water quality improvement. In this paper, we sampled six types of wetlands representing different kinds of land utilisation around the TaiHu Lake Basin in southeast China. An outdoor computerized microcosm was set up in May 2008 to simulate climate scenarios of ambient temperature (control) and a warmed ambient temperature (+5 °C) using a novel minute-scale daily and seasonal temperature manipulation technology. The 18-month incubation indicated that warming impaired the ecological sink of sediment (fixing P from porewater) while strengthening the role of the ecological source, moreover, the rate of P release from sediment into porewater (19–113% for total phosphorus) was much stronger than from top sediment into overlying water. Warming enhanced the activity of neutral and alkaline phosphatases for P-deficient wetland sediments and neutral phosphatases for P-rich sediments, at the 14th month of incubation. A significant increase in total phospholipid fatty acids (PLFAs) occurred under warming in sediments with relatively low levels of PLFAs, but bacterial abundance in the sediment biomass tended to decrease (18%) along with an increase (4·5%) of the fungi-to-bacteria ratio. The variations of carbon consumption and availability indicated by measured dissolved organic carbon in sediment may have contributed to P release from sediments to water. Copyright © 2011 John Wiley & Sons, Ltd.

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