Copper pollution decreases the resistance of soil microbial community to subsequent dry–rewetting disturbance

• Published in: Journal of environmental sciences (China) Vol. 39; no. 1; pp. 155 - 164
• Main Authors: Li, Jing, Wang, Jun-Tao, Hu, Hang-Wei, Ma, Yi-Bing, Zhang, Li-Mei, He, Ji-Zheng
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 2016
• Subjects: Bacteria - drug effects; bacterial communities; Bacterial community; Bacterial Physiological Phenomena - drug effects; Biodiversity; community structure; Copper - toxicity; Copper stress; Dry–rewetting disturbance; heavy metals; irrigation; pollution; rain; Resistance; soil; Soil - chemistry; Soil Microbiology; soil microorganisms; Soil Pollutants - toxicity; Stress, Physiological - drug effects; structural equation modeling; Substrate induced respiration; variance; Wettability; 土壤微生物群落; 土壤重金属污染; 干燥; 底物诱导呼吸; 微生物群落结构; 抗干扰能力; 数据仓库技术; 铜污染; Resistance; Copper stress; Dry–rewetting disturbance; Bacterial community; Substrate induced respiration
• ISSN: 1001-0742; 1878-7320
• DOI: 10.1016/j.jes.2015.10.009

Dry–rewetting（DW） disturbance frequently occurs in soils due to rainfall and irrigation, and the frequency of DW cycles might exert significant influences on soil microbial communities and their mediated functions. However, how microorganisms respond to DW alternations in soils with a history of heavy metal pollution remains largely unknown.Here, soil laboratory microcosms were constructed to explore the impacts of ten DW cycles on the soil microbial communities in two contrasting soils（fluvo-aquic soil and red soil）under three copper concentrations（zero, medium and high）. Results showed that the fluctuations of substrate induced respiration（SIR） decreased with repeated cycles of DW alternation. Furthermore, the resistance values of substrate induced respiration（RS-SIR）were highest in non-copper-stressed（zero） soils. Structural equation model（SEM） analysis ascertained that the shifts of bacterial communities determined the changes of RS-SIR in both soils. The rate of bacterial community variance was significantly lower in noncopper-stressed soil compared to the other two copper-stressed（medium and high） soils,which might lead to the higher RS-SIR in the fluvo-aquic soil. As for the red soil, the substantial increase of the dominant group WPS-2 after DW disturbance might result in the low RS-SIR in the high copper-stressed soil. Moreover, in both soils, the bacterial diversity was highest in non-copper-stressed soils. Our results revealed that initial copper stress could decrease the resistance of soil microbial community structure and function to subsequent DW disturbance.