Di-(2-ethylhexyl) phthalate (DEHP) exposure significantly decreased soil nitrification through inhibiting ammonia-oxidizing bacteria and destabilizing their co-occurrence networks

• Published in: Environmental technology & innovation Vol. 35; p. 103682
• Main Authors: Zhang, Hanjie, Ye, Zhuang, Gu, Xiuping, Hu, Baowei, Wakelin, Steve A., Chu, Guixin
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.08.2024
• Subjects: Ammonia oxidizers of AOA and AOB; Calcareous soil; Di-(2-ethylhexyl) phthalate; Microbial co-occurrence network; Nitrification potential; Nitrification potential; Di-(2-ethylhexyl) phthalate; Calcareous soil; Ammonia oxidizers of AOA and AOB; Microbial co-occurrence network
• ISSN: 2352-1864; 2352-1864
• DOI: 10.1016/j.eti.2024.103682

Di-(2-ethylhexyl) phthalate (DEHP) has increasingly accumulated in soils due to DEHP-containing plastic film has been extensively used in agriculture. However, the exposure of DEHP on calcareous soil nitrification potential, ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) are poorly investigated. Here, an incubation experiment was established containing four treatments:(ⅰ) unfertilized blank control, (ⅱ) urea addition alone, (ⅲ) urea plus DEHP (10 mg kg-1), (ⅳ) urea plus DEHP (100 mg kg-1). The influences of DEHP exposure on soil NH4+-N, NO3--N, soil potential nitrification rate (PNR), ammonia monooxygenase (AMO) activity, AOA and AOB were analyzed. We found that DEHP exposure (10 and 100 mg kg-1) lowered NO3--N in the treatments of urea plus DEHP10 and urea plus DEHP100, and it significantly decreased soil PNR and AMO activity. Also, the exposure of DEHP reduced the numbers of AOA and AOB gene copies, and decreased AOB community’s α-diversity. Moreover, DEHP exposure destabilized AOB community’s co-occurrence network and decreased key module abundance, but its influences on AOA community was not significant. Taken together, the exposure of DEHP inhibited PNR in a calcareous soil through decreasing AOB gene copies and weakening the co-occurrence network of AOB community. Our findings provide a novel insights into microbial mechanisms about the detrimental effects of DEHP pollution on soil PNR and nitrification process in calcareous soil. [Display omitted] •DEHP exposure significantly suppressed soil potential nitrification rate (PNR)•Nitrifiers of AOB was more susceptible than AOA community to DEHP exposure•DEHP exposure destabilized the co-occurrence network of AOB community