State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Institute of Plant Virology, Ningbo University, Ningbo 315211, China.
Centre for Environmental and Climate Science, Lund University, 22362 Lund, Sweden.
J Hazard Mater. 2021 Aug 15;416:126221. doi: 10.1016/j.jhazmat.2021.126221. Epub 2021 May 26.
Microplastics (MPs) are a widespread pollutant in terrestrial ecosystems. However, knowledge on how MPs impact soil organic matter (SOM) decomposition and the priming effect (PE) in rice paddy soil remains limited. By employing a three-source-partitioning approach, we investigated the interactive impact of MP dosage (none, low [0.01% w/w] or high [1% w/w]), labile C (C-labeled glucose), and C-labeled rice straw addition on SOM decomposition and PE. Compared to soil without C addition (i.e., control), total SOM-derived CO in low-MP soil declined by 13.2% and 7.1% after straw and glucose addition, respectively. Under combined glucose and rice straw addition, glucose-induced PE was up to 10 times stronger in the presence of low-MPs compared to that in high-MPs. However, glucose induced negative PE on rice straw decomposition in the presence of MPs. SOM decomposition was much higher under low MP dosage than under high MP dosage. However, MPs had a negligible effect on the mineralization of exogenous C substrate (glucose or straw). This study provides a novel and valuable insight on how MPs affect SOM turnover and C sequestration in paddy soil, highlighting the significance of interactions between environmental pollutants and biogeochemical processes that affect CO fluxes.
微塑料（MPs）是陆地生态系统中广泛存在的污染物。然而，关于 MPs 如何影响土壤有机质（SOM）分解和水稻土中的激发效应（PE）的知识仍然有限。本研究采用三源分区法，研究了 MP 剂量（无、低[0.01% w/w]或高[1% w/w]）、易位碳（C 标记葡萄糖）和 C 标记稻草添加对 SOM 分解和 PE 的相互影响。与未添加 C 的土壤（即对照）相比，低 MP 土壤中添加稻草和葡萄糖后，总 SOM 衍生 CO 分别减少了 13.2%和 7.1%。在葡萄糖和稻草联合添加下，低 MPs 存在时葡萄糖诱导的 PE 比高 MPs 存在时强 10 倍。然而，在 MPs 存在的情况下，葡萄糖对稻草分解产生了负激发效应。在低 MP 剂量下，SOM 分解比高 MP 剂量下高得多。然而，MPs 对外源 C 底物（葡萄糖或稻草）的矿化几乎没有影响。本研究提供了一个关于 MPs 如何影响水稻土中 SOM 周转和 C 固存的新的有价值的见解，强调了环境污染物与影响 CO 通量的生物地球化学过程之间相互作用的重要性。
