Non-additive effects of mixing different sources of dissolved organic matter on its biodegradation |
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| Institution: | 1. College of Horticulture and Forestry Sciences/Hubei Engineering Technology Research Center for Forestry Information, Huazhong Agricultural University, Wuhan 430070, China;2. Research Institute of Forest Ecology Environment and Protection/State Forestry Administration Key Laboratory of Forest Ecology and Environment, Chinese Academy of Forestry, Beijing 100091, China;3. Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing 210037, China |
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| Abstract: | To examine the potential impact of plant species richness on ecosystems, we studied non-additive effects of different plant litters on the biodegradation rate of dissolved organic matter (DOM) when mixing plant leaf-derived DOM derived from different plant species. A full factorial biodegradation experiment (31 possible singular and multiple combinations of five litter type-derived DOM sources) was conducted using plant litters from the five most abundant plant species in a subtropical watershed ecosystem, from which dissolved organic carbon (DOC) disappearance was measured. Loss of DOC over time was considered biodegradable DOC. We tested whether DOM diversity, measured as source species richness and composition, would affect biodegradation rates. Overall, we found significant non-additive (synergistic) effects of DOM diversity on biodegradation rates of DOM, which were explained both by plant species richness and composition. Across all treatments, a significantly higher biodegradation rate was correlated with the presence of DOM from higher nitrogen (N) containing plant litters; conversely, the presence of lower N decreased these rates. The N content and chemical characteristic of DOM might influence the magnitude of the synergistic effect. Our results suggest that loss of plant litter species diversity would not affect DOC biodegradation rate, provided that at least two species are conserved. However, the variability in DOC biodegradation rate across the treatments decreased with increased DOM diversity at three incubation time points. Our results also indicate that in an ecosystem with low plant biodiversity, loss of key species such as Lophostemon confertus could reduce the synergistic effects on DOC biodegradation rate. |
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| Keywords: | Non-additive effect Biodegradation Litters Dissolved organic carbon NMR |
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