Dual regulatory effects of microplastics and heat waves on river microbial carbon metabolism

• Published in: Journal of hazardous materials Vol. 441; p. 129879
• Main Authors: Wang, Zhongwei, Hu, Xiangang, Qu, Qian, Hao, Weidan, Deng, Peng, Kang, Weilu, Feng, Ruihong
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 05.01.2023
• Subjects: K-/r- strategy; Keystone taxa; Microbial community; Thermal adaptation; Warming; Warming; Keystone taxa; Thermal adaptation; K-/r- strategy; Microbial community
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2022.129879

Rivers play a critical role in the global carbon cycle, but the processes can be affected by widespread microplastic (MP) pollution and the increasing frequency of heat waves (HWs) in a warming climate. However, little is known about the role of river microbes in regulating the carbon cycle under the combined action of MP pollution and HWs. Here, through seven-day MP exposure and three cycles of HW simulation experiments, we found that MPs inhibited the thermal adaptation of the microbial community, thus regulating carbon metabolism. The CO2 release level increased, while the carbon degradation ability and the preference for stable carbon were inhibited. Metabonomic, 16 S rRNA and ITS gene analyses further revealed that the regulation of carbon metabolism was closely related to the microbial r-/K- strategy, community assembly and transformation of keystone taxa. The random forest model revealed that dissolved oxygen and ammonia-nitrogen were important variables influencing microbial carbon metabolism. The above findings regarding microbe-mediated carbon metabolism provide insights into the effect of climate-related HWs on the ecological risks of MPs. [Display omitted] •MPs regulate the carbon metabolism in river under HWs via microbial communities.•Reduction of community thermal adaptation prefers to deterministic processes.•Under MPs and HWs, the bacterial community exhibited a more positive response.•Transformation of keystone taxa reduces the complexity of the co-occurrence network.•There are connections between water quality and carbon metabolic index.