Carbon sequestration in terrestrial ecosystems plays an essential role in coping with global climate change and achieving regional carbon neutrality. In mining areas with high groundwater levels in eastern China, underground coal mining has caused severe damage to surface ecology. It is of practical significance to evaluate and predict the positive and negative effects of coal mining and land reclamation on carbon pools. This study set up three scenarios for the development of the Yanzhou coalfield (YZC) in 2030, including: (1) no mining activities (NMA); (2) no reclamation after mining (NRM); (3) mining and reclamation (MR). The probability integral model (PIM) was used to predict the subsidence caused by mining in YZC in 2030, and land use and land cover (LULC) of 2010 and 2020 were interpreted by remote sensing images. Based on the classification of land damage, the LULC of different scenarios in the future was simulated by integrating various social and natural factors. Under different scenarios, the InVEST model evaluated carbon storage and its temporal and spatial distribution characteristics. The results indicated that: (1) By 2030, YZC would have 4341.13 ha of land disturbed by coal mining activities. (2) Carbon storage in the NRM scenario would be 37,647.11 Mg lower than that in the NMA scenario, while carbon storage in the MR scenario would be 18,151.03 Mg higher than that in the NRM scenario. Significantly, the Nantun mine would reduce carbon sequestration loss by 72.29% due to reclamation measures. (3) Carbon storage has a significant positive spatial correlation, and coal mining would lead to the fragmentation of the carbon sink. The method of accounting for and predicting carbon storage proposed in this study can provide data support for mining and reclamation planning of coal mine enterprises and carbon-neutral planning of government departments.

Polycyclic aromatic hydrocarbons (PAHs) are typical high-risk, persistent organic pollutants. Biological slurry reactors are widely used for enhanced bioremediation. In this experiment, a highly efficient phenanthrene-degrading bacteria group was obtained through screening and domestication, and the community was named MZJ_21. After the addition of MZJ_21 to the aerobic slurry bioreactor, with the optimum conditions of the temperature, stirring speed, and aeration rate of 30 °C, 120 rpm, and 1 L/min, respectively, the phenanthrene degradation ratio reached 95.41% within 48 h. The exploration of the degradation of phenanthrene by MZJ_21 indicated that most MZJ_21 communities adsorbed on the soil particle, mainly because MZI_21 could secrete extracellular polymers, which could stably adhere MZJ_21 on the solid phase. At the same time, the distribution ratio of phenanthrene in the solid phase is increased, so that the efficient phenanthrene degradation reaction takes place in the solid phase.

The degradation of polycyclic aromatic hydrocarbons has attracted much attention. Based on toluene-catechol-anthracene multi-substrate progressive domestication, a mixed microbial consortium with synergistic metabolic activity was screened from the activated sludge of coking wastewater. High-throughput sequencing showed that the consortium was dominated by Flavobacteriia at the class level, with the proportion increasing from 8.88% to 56.41% after domestication, and that Myroides and Brevundimonas dominated at the genus level, increasing from less than 1% to 55.53% and 12.28%, respectively. Under temperature conditions of 30 °C, a pH of 7, and an initial anthracene concentration of 40 mg L-1, the degradation ratio reached 85.7% just 16 days after inoculation. Degradation ratio of Anthracene (40 mg L-1) via the consortium plus an indigenous strain Pseudomonas_aeruginosa DM3 on the sixth day (83%) equated to that in the control group without DM3 on the 12th day. The first-order rate constant (k=0.240 and 0.159 d-1) was calculated for the anthracene degradation within 10 days, with a corresponding half-life by the consortium of 2.9 days with DM3 and 4.4 days without DM3. The metabolites 1-naphthol, dibutyl phthalate, and 1,2-benzene dicarboxylic acid, mono (2-ethylhexyl) ester were presented in the reaction, inferring the metabolic pathway of phthalic acid. Our work revealed that inoculating the mixed microbial consortium with indigenous Pseudomonas aeruginosa DM3 has the potential for removing polycyclic aromatic hydrocarbons.