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The global temperature is continuously rising, and the impacts of nighttime warming (NW) and daytime warming (DW) on ecosystems have drawn widespread attention. However, most studies on the effects of daytime and nighttime warming on ecosystems have focused primarily on aboveground processes, but little is known about how they affect underground processes, particularly soil microorganisms. Therefore, we examined the effects of daytime and nighttime experimental warming (CK: control, DW: daytime warming, NW: nighttime warming, DW + NW: daily warming) on soil bacterial and fungal diversities at the Experimental Station of Zengcheng Forestry Science Research Institute in Guangdong, China. The results showed that, compared with the CK treatment, the NW rather than DW treatment significantly increased the abundance-based coverage estimator (ACE) diversity index of bacteria and fungi. Fungal beta diversity significantly differed between the DW and NW treatments, while there was no significant difference in bacterial beta diversity. Our research indicated that the NW treatment creates a more favourable microenvironment than the DW treatment, accelerating the mineralization of soil carbon, nitrogen, and phosphorus nutrients, which may be the reason for changes in microbial diversity. Our study provides important theoretical support and practical guidance for predicting the impact of global climate change on the diversity of microbial ecosystems.

The potential risks of vapor intrusion (VI) can arise from low bulk soil contaminant concentration existing in shallow soils beneath a building foundation. To assess VI risks for such a contamination scenario, a comprehensive study was conducted on a factory building located at a trichloroethylene (TCE)-contaminated site. This study involved the integration of various types of field data, including groundwater, bulk soil, soil gas and indoor air data, along with the utilization of the Vapor Intrusion Screening Level (VISL) calculator. Previously observed high TCE concentrations in soil gas are attributed to accumulation of TCE vapor within the unsaturated soil beneath the building floor, since ground surface is extensively paved at this site. These soil gas data do not directly correlate with the magnitudes of bulk soil and/or groundwater TCE concentration with the linear adsorption model. Soil gas TCE concentration exceeding 107 μg/m³ (or bulk soil concentration exceeding 18.9 mg/kg) observed in shallow soils (at a depth of less than 1 m) may pose health risk to the workers inside the building due to VI, as we have detected TCE vapor concentrations exceeding indoor air screening level several times in the past. This bulk soil TCE concentration, however, falls below soil pollution control standards for TCE, i.e., 60 mg/kg, in Taiwan. As a result, soil remediation is not considered at this site. Soil gas TCE concentrations have reduced to less than 106 μg/m³ after two years of groundwater remediation work at this site. However, we have observed significantly higher soil gas TCE levels at a depth of 0.5 m compared to other depths. This discrepancy raises suspicions that an amount of TCE may still be trapped within the shallow soils that are not reached by groundwater table. [ABSTRACT FROM AUTHOR]