土壤中聚乙烯和聚乳酸微塑料污染对微生物残体和植物木质素的碳积累的差异影响。
Differential carbon accumulation of microbial necromass and plant lignin by pollution of polyethylene and polylactic acid microplastics in soil.
机构信息
State Key Laboratory of Environmental Criteria and Risk Assessment, and State Environmental Protection Key Laboratory of Simulation and Control of Groundwater Pollution, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China; School of Resources and Environment Engineering, Mianyang Teachers' College, Mianyang, 621000, China; School of Chemical and Environmental Engineering, China University of Mining and Technology (Beijing), Beijing, 100083, China.
School of Resources and Environment Engineering, Mianyang Teachers' College, Mianyang, 621000, China.
出版信息
Environ Pollut. 2024 Oct 1;358:124504. doi: 10.1016/j.envpol.2024.124504. Epub 2024 Jul 3.
The wide microplastics (MPs) occurrence affects soil physicochemical and biological properties, thereby influencing its carbon cycling and storage. However, the regulation effect of MPs on soil organic carbon (SOC) formation and stabilization remains unclear, hindering the accurate prediction of carbon sequestration in future global changes under continuous MP pollution. Phospholipid fatty acids, amino sugars and lignin phenols were used in this study as biomarkers for microbial community composition, microbial necromass and plant lignin components, respectively, and their responses to conventional (polyethylene; PE) and biodegradable (polylactic acid; PLA) MPs were explored. Results showed PLA MPs had positive effects on soil microbial biomass, while the positive and negative effects of PE MPs on microbial biomass varied with MP concentration. PE and PLA MPs increased microbial necromass contents and their contribution to SOC, mainly due to the increase in fungal necromass. On the contrary, PE and PLA MPs reduced lignin phenols and their contribution to SOC, mainly owing to the reduction in vanillyl-type phenols. The response of microbial necromass to PLA MPs was higher than that to PE MPs, whereas the response of lignin phenols was the opposite. MPs increased SOC level, with 83%-200% and 50%-75% of additional SOC in PE and PLA treatments, respectively, originating from microbial necromass carbon. This finding indicates that the increase in SOC pool in the presence of MPs can be attributed to soil microbial necromass carbon, and MPs increased capacity and efficacy of microbial carbon pump by increasing microbial turnover and reducing microbial N limitation. Moreover, the increase in amino sugars to lignin phenols ratio in PE treatment was higher than that in PLA treatment, and the increase in SOC content in PLA treatment was higher than that in PE treatment, indicating a high possibility of SOC storage owing to PLA MPs.
广泛存在的微塑料（MPs）会影响土壤理化和生物学特性，从而影响其碳循环和储存。然而，MPs 对土壤有机碳（SOC）形成和稳定的调节作用尚不清楚，这阻碍了在持续的 MP 污染下，未来全球变化中对碳固存的准确预测。本研究分别使用磷脂脂肪酸、氨基糖和木质素酚作为微生物群落组成、微生物残体和植物木质素成分的生物标志物，并探索了它们对常规（聚乙烯；PE）和可生物降解（聚乳酸；PLA） MPs 的响应。结果表明，PLA MPs 对土壤微生物生物量有积极影响，而 PE MPs 对微生物生物量的积极和消极影响随 MP 浓度而变化。PE 和 PLA MPs 增加了微生物残体含量及其对 SOC 的贡献，主要是由于真菌残体的增加。相反，PE 和 PLA MPs 减少了木质素酚及其对 SOC 的贡献，主要是由于香草型酚的减少。微生物残体对 PLA MPs 的响应高于对 PE MPs 的响应，而木质素酚的响应则相反。MPs 增加了 SOC 水平，PE 和 PLA 处理分别使 SOC 增加了 83%-200%和 50%-75%，源于微生物残体碳。这一发现表明，在 MPs 存在的情况下，SOC 库的增加可以归因于土壤微生物残体碳，并且 MPs 通过增加微生物周转和减少微生物 N 限制，增加了微生物碳泵的能力和效率。此外，PE 处理中氨基糖与木质素酚比值的增加高于 PLA 处理，PLA 处理中 SOC 含量的增加高于 PE 处理，表明由于 PLA MPs，SOC 储存的可能性较高。
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