Microbial fuel cells (MFC) can use microorganisms to directly convert the chemical energy of organic matter into electrical energy, and generate electrical energy while pollutants degradation. To solve the critical problem of lower power yield of power production, this study selected Saccharomyces cerevisiae, Escherichia coli, Pseudomonas aeruginosa, and Bacillus subtilis as the anodic inoculums. The influence of the mixed bacteria on the power-producing effect of MFC and the synergy effect between the electrochemically active bacteria in mixed cultures were discussed. The results showed that among the mixed culture system, only the mixed cultures MFC composed of Saccharomyces cerevisiae and Bacillus subtilis had a significant increase in power generation capacity, which could reach to 554 mV. Further analysis of the electrochemical and microbiological performance of this system was conducted afterward to verify the synergy effect between Saccharomyces cerevisiae and Bacillus subtilis. The riboflavin produced by Bacillus subtilis could be utilized by Saccharomyces cerevisiae to enhance the power generation capacity. Meanwhile, Saccharomyces cerevisiae could provide carbon source and electron donor for Bacillus subtilis through respiration. Finally, in the experiment of adding exogenous riboflavin in the mixed bacterial MFC, the result indicated that the mixed bacterial MFC chose the self-secreting riboflavin over the exogenous riboflavin as the electron mediator, and the excess riboflavin might hinder the electron trasfer. Graphical abstract

Land resources are foundational for human survival and development. In contrast, land use/land cover (LULC) dynamics drive considerable changes in ecosystem services. Recently, China witnessed a new stage of rapid urbanization. Therefore, investigating the relationships between ecosystem services value (ESV) and LULC in these areas is highly relevant. Based on the data of land use and socioeconomic development in Shanghai from 2000 to 2020, we adopted a land use/land cover dynamics analysis method and established the ESV per unit area at the city scale, discussed the impact of LULC on ESV spatially and quantitatively, and tested the research process based on the sensitivity analysis of the ESV coefficient. The results show that from 2000 to 2020, the LULC pattern in Shanghai rapidly changed. In particular, the area of cultivated land has shrunk by 123.96 thousand hm², while the construction land has expanded by 141.26 thousand hm², which has led to a decline in ESV of the entire city (especially regarding hydrological adjustment and biodiversity). Nevertheless, although the area of trench and lakes only occupies 1.67–3.16% of the total area of land, its ecological value accounts for an astonishing 23.80–50.70% of the total ESV. At the district level, the primary decline in eco-system services value was noted in the Chongming District in the north and Pudong New Area in the east of Shanghai. However, due to the overall planning of the city and the advantages of its resource endowment, Qingpu District and its surrounding areas in western Shanghai have witnessed improvements in terms of the values of hydrological adjustment, water supply, and environmental purification. This study presents a deeper and more comprehensive understanding of issues regarding ESV in rapidly urbanized areas, thereby providing an important reference for decision-makers regarding the rational layout of cities, sustainable use of land, and management of natural ecosystems.

In order to protect wetland resources, China has developed wetland conservation policies and has made significant conservation investments, but there is still a lack of pathways for the conversion to economic value, making it difficult to meet the demand for continuous investment. We have explored a sustainable ecological conservation mechanism using the Seven Mile Sea as a case study, so that ecological conservation costs can be transformed into economic development behaviors and ecological benefits and socio-economic development can be integrated. This paper assesses the ecological product value of the Qilihai Wetland based on the ecosystem service function value assessment method, which designs the realization path of ecological product value and predicts the value transformation efficiency. The results show the following: (1) The total value of ecological products in the study area is CNY 569.06 million (USD 78.36 million), and the main sources of value are plant products in the supply service and water purification functions in the regulation service, accounting for 54.05% and 26.10% of the total, respectively. (2) The predicted value realization of ecological products, ideally, is CNY 689.65 million (USD 94.96 million), with a value realization rate of 111.60%. Considering the management policy restrictions in different areas of the Qilihai Wetland, the actual value realization volume is CNY 391.94 million (USD 53.97 million), with a value realization rate of 63.42%. (3) Owing to the restriction of the development policy of supply services and cultural services, the value realization path mainly contains two types: one is to drive the development of supply services and cultural services in the surrounding areas, along with product premiums, to realize value transformation. This path is mainly aimed at the supply of local characteristic products and the development of tourism. The second is to realize the value of regulating services through ecological compensation and ecological equity trading. This path is mainly for the adjustment and support services in the core area and buffer area. According to the pre-accounting results, the contribution rates of the two paths are 62.25% and 37.75%, respectively. The second path should be further effectively developed to improve the contribution rate. This study helps assess the ecological value and important ecological elements of the Qilihai Wetland to ensure effective protection and development of important ecological resources and to achieve the sustainable development of wetland resources. It provides a reference for exploring feasible paths to realize the value of ecological goods.

Coronavirus disease 2019 has significantly impacted mental health. Urban green spaces’ ecological function can improve citizens’ well-being and mental health; thus, this study explored the value realisation mechanism of ecological products in green space by examining the impact of urban green space soundscape on citizens’ emotions. Additionally, we investigated citizens’ subjective perceptions and emotional changes in soundscape through questionnaires. An A-weighted sound pressure level meter was used to measure the sound pressure levels at three points in a day to obtain the sound pressure level changes during different day periods in a park. Subsequently, the universal conclusion through a comparative analysis of the sound pressure level change in urban parks during the day was roughly ‘M’ shape. Further, a structural equation model analysed the influence of different soundscape on public sentiment and used a multigroup analysis to examine the difference in the impact of natural sounds in summer and winter on the change in public opinion. The results show that natural and living sounds positively affect citizens’ emotions, whereas mechanical sounds negatively affect citizens’ emotions. Furthermore, natural sounds in summer positively affect citizens’ moods significantly. Conversely, natural sounds in winter negatively affect citizens’ attitudes, but this is not obvious. Finally, this study proposed some suggestions for managing and improving urban green space soundscape.

The digital economy is an important driving force for promoting national economic growth and achieving high-quality economic transformation, and is a key force in achieving the sustainable development goals (SDGs). This paper measures the digital economy development level of 30 provinces in China from 2013 to 2021 utilizing the entropy of weighting approach, and in order to further reveal its intrinsic laws and differences, it uses three-dimensional kernel density analysis, the Dagum Gini coefficient, spatial autocorrelation analysis, and cold hot spot analysis to explore the spatial and temporal evolution characteristics of the digital economy and its regional imbalance. The empirical results show that ① China’s digital economy has been steadily increasing, spatially showing the characteristics of gradual decrease from east to west and from coast to inland, with obvious spatial agglomeration characteristics and an increasing trend. ② There are obvious regional imbalances in the digital economy, with the southeast coastal region leading significantly. ③ The overall regional differences are large but reduced, mainly from intra-regional differences, the and inter-regional contribution is low. The research in this paper provides data support for revealing the spatial and temporal evolution characteristics of digital economic development and provides new path support for the balanced development of China’s regional digital economy.

Background: Air pollution has aroused global concerns because of its adverse effects on individuals’ physical and psychological health and behavior. Although there has been substantial traditional consideration of the objective impact of air pollution, more knowledge is needed about perceived air quality (PAQ), its association with objective air pollution (OAP), and the relationship between OAP and PAQ with respect to pro-environmental behavior (PEB). Methods: To delineate and investigate the effect of air pollution on both perceived and objective perspectives of PEB and its underlying psychological mechanisms, this study distributed a survey questionnaire related to PAQ, the Positive and Negative Affect Schedule (PANAS), satisfaction with local governmental control of air quality (SAT), and the PEB scale. The monitored data of objective city-level air pollution and 391 samples of survey data were included in this study. Results: The results reveal that both PAQ and OAP increase individuals’ negative affect (NA) and decrease SAT, which sequentially restrains PEB. More importantly, PAQ, NA, and SAT played mediating roles in the relationship between OAP and PEB. Empirical testing for group difference also indicated that while there is no gender-related difference with respect to caring about SAT and PEB caused by air pollution, gender effects on NA were significantly different. Age-related differences exist among younger, medium, and older age groups with respect to NA, SAT, and PEB caused by air pollution, and there are also background differences with respect to NA, SAT, and PEB, although income does not generate a significant group difference effect on NA, SAT, and PEB. Conclusions: The findings corroborate the important roles of affect and SAT in activating public concern about air quality. We discuss the possible ways that affect and SAT might enhance PEB as well as the limitations of this study. More pollutants and mechanisms could be considered in future studies.