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Huang W.,Nanjing Forestry University | Ruan H.-H.,Nanjing Forestry University | Xu Z.-K.,Administrative Bureau of Wuyi Mountain National Nature Reserve
Chinese Journal of Ecology | Year: 2014

Dissolved organic carbon (DOC) in freshwater is an important component of the global carbon cycle, and is also carbon and energy source for heterotrophs in freshwater. The response of freshwater DOC to global change will affect the size of global carbon sink, and structure and function of freshwater ecosystems. We reviewed the influence of global change on freshwater DOC, and the feedback of freshwater DOC dynamics to climate change. We pointed out that interactions among global change factors affected freshwater DOC, and the influencing degrees of global change factors varied with time and space. The feedback of freshwater DOC to global change was also substantially different across time and space. But there is little information regarding the feedback of freshwater DOC to global change, and much less is known about the feedback mechanism of freshwater DOC to global change. Based on present researches, more attention should be devoted to the three aspects: (1) to expand research areas to understand the temporal dynamic characteristics of DOC in freshwater ecosystems in different regions; (2) to better understand the effect of global change on DOC composition and structure in freshwater ecosystems; and (3) to gain better insight into the feedback degree and mechanism of freshwater DOC to global change.


Jin Y.-H.,Nanjing Forestry University | Wang J.-S.,Administrative Bureau of Wuyi Mountain National Nature Reserve | Li L.-G.,Nanjing Forestry University | Ruan H.-H.,Nanjing Forestry University | And 2 more authors.
Chinese Journal of Ecology | Year: 2011

This paper measured the activities of soil urease, sucrase, acid phosphatase, and catalase in four typical vegetation zones, i. e., evergreen broadleaf forest (EBF), coniferous forest (CF), sub-alpine dwarf forest (SDF), and alpine meadow (AM), along an altitude gradient in the Natural Reserve of the Wuyi Mountains in Fujian Province of East China. In the four zones, there were no significant seasonal variations in the activities of test enzymes except acid phosphatase, whose activity was significantly higher in autumn than in any other seasons. The activities of test enzymes differed significantly with altitude, but less affected by the interaction of season and altitude. The enzyme activities showed an overall increasing trend with the altitude, being significantly higher in AM zone than in EBF and CF, and decreased with soil depth. The soil urease activity in the four zones was in the range of 1.28-3.87 mg • g-1 •24 h-1, and in the order of AM>EBF>SDF>CF; soil sucrase activities was in the range of 36.18-244.08 mg • g-1 • 24 h-1, and in the order of AM>CF>EBF>SDF; acid phosphatase and catalase activities were in the ranges of 0. 18-0.62 mg • g-1 • 2 h-1 and 1. 78-1. 98 ml • g-1 • 20 min-1, respectively, and in the order of AM>CF>SDF>EBF. The soil enzyme activities were significantly positively correlated with soil total organic carbon and total nitrogen, and had complicated correlations with soil temperature, moisture, and pH.

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