Soil Abiotic Properties and Plant Functional Traits Mediate Associations Between Soil Microbial and Plant Communities During a Secondary Forest Succession on the Loess Plateau

In the context of secondary forest succession, aboveground-belowground interactions are known to affect the dynamics and functional structure of plant communities. However, the links between soil microbial communities, soil abiotic properties, plant functional traits in the case of semi-arid and arid ecosystems, are unclear. In this study, we investigated the changes in soil microbial species diversity and community composition, and the corresponding effects of soil abiotic properties and plant functional traits, during a ≥150-year secondary forest succession on the Loess Plateau, which represents a typical semi-arid ecosystem in China. Plant community fragments were assigned to six successional stages: 1–4, 4–8, 8–15, 15–50, 50–100, and 100–150 years after abandonment. Bacterial and fungal communities were analyzed by high-throughput sequencing of the V4 hypervariable region of the 16S rRNA gene and the internal transcribed spacer (ITS2) region of the rRNA operon, respectively. A multivariate variation-partitioning approach was used to estimate the contributions of soil properties and plant traits to the observed microbial community composition. We found considerable differences in bacterial and fungal community compositions between the early (S1–S3) and later (S4–S6) successional stages. In total, 18 and 12 unique families were, respectively, obtained for bacteria and fungi, as indicators of microbial community succession across the six stages. Bacterial alpha diversity was positively correlated with plant species alpha diversity, while fungal diversity was negatively correlated with plant species diversity. Certain fungal and bacterial taxa appeared to be associated with the occurrence of dominant plant species at different successional stages. Soil properties (pH, total N, total C, NH4-N, NO3-N, and PO4-P concentrations) and plant traits explained 63.80% and 56.68% of total variance in bacterial and fungal community compositions, respectively. These results indicate that soil microbial communities are coupled with plant communities via the mediation of microbial species diversity and community composition over a long-term secondary forest succession in the semi-arid ecosystem. The bacterial and fungal communities show distinct patterns in response to plant community succession, according to both soil abiotic properties and plant functional traits

Knowledge base to facilitate anthropogenic resource assessment

The traditional mining sector uses resource assessments to estimate the mineability of natural resources. The results are communicated to investors, authorities and corporate management boards in a standardized manner, at least on a country level. The recycling sector also requires estimates of recoverable anthropogenic resources. Evidence-based resource assessment, including the selection of parameters for characterising resources and methods for assessing their recoverability, is essential to obtain comparable estimates over time and across scales. Within this report, the COST Action MINEA presents a practical and user-friendly knowledge base for facilitating anthropogenic resource assessments. The fouces is on extractives industry residues, residues in landfills, residues from municipal solid waste incineration as well as construction & demolition waste flows. The key objectives are: To relate current knowledge levels, gaps and future needs to assessments of viability of anthropogenic resource recovery. To review case studies that demonstrate anthropogenic resource assessment in combination with resource classification in order to communicate the viability of anthropogenic resource recovery. We encourage academics, businesses and government organisations to use this report for: designing and developing case studies, future planning, developing standards for characterizing resource quantities and evaluating their recoverability, and collecting and harmonizing resource statistics. ************* The “Mining the European Anthroposphere” (MINEA) is a pan-European expert network, which received funding from the COST Association between 2016 and 2020. The network pools knowledge for estimating the future recoverability of raw materials from anthropogenic resources

Low-Carbon Sustainable Development of 5G Base Stations in China

With the construction of new infrastructure is on the rise in many countries, the impact of the 5G developments on circular economy in the era of COVID-19 cannot be overlooked. However, the high energy consumption and rapid construction speed of new infrastructure have led to increased concern about the carbon emissions generated during the operation process. As 5G serves as the foundation for the construction of new infrastructure, China, as the world leader in 5G base station construction, has already built over 1.4 million 5G base stations in 2021 alone. In the same year, 5G base stations in China produced approximately 49.2 million tons of CO2eq. In order to increase the contribution of the communication industry to mitigate the global greenhouse effect, future efforts must focus on reducing the carbon emissions associated with 5G base station construction from four key perspectives: network architecture, network deployment, resource scheduling, and link-level technology. In this way, the 5G network can achieve sustainable development

Uncovering the Carbon Emission Intensity and Reduction Potentials of the Metro Operation Phase: A Case Study in Shenzhen Megacity

The huge energy consumption of metro operations has become a significant challenge faced by the urban public transportation sector to achieve low-carbon development. Using Shenzhen as an example, this study has made efforts to quantify the metro’s energy consumption and carbon emission intensity during the operation phase by using the Life Cycle Assessment approach. Furthermore, this study evaluates the actions that can be taken to reduce energy consumption and emissions. A comparative analysis between metros and other public transportation modes has also been conducted. The results show that the annual carbon emissions from the metro’s operation phase in Shenzhen city increased from 63,000 t CO2e in 2005 to 1.3 Mt CO2e in 2021, and the historically accumulated carbon emissions are 9.5 Mt CO2e. The unit operating mileage, the unit station area, and the per capita carbon emission intensity were 2.1 kg CO2e/km, 132.5 kg CO2e/m2, and 0.6 kg CO2e per capita (13th Five-Year Plan Period), respectively. By continually promoting the low-carbon operation of the subway, the cumulative carbon savings could reach 0.1 Mt CO2e (2022–2035)

Development patterns, material metabolism, and greenhouse gas emissions of high-speed railway in China

Abstract China built the longest high-speed railway system by consuming massive construction materials. However, characterization material metabolism in HSR system remains less explored. Here we conducted a bottom-up material metabolism study and revealed the material stocks, flows, and greenhouse gas emissions from 2008 to 2035 in China’s high-speed railway. We show that material stocks temporally amount from 0.6 gigatons in 2010 to 3.7 gigatons in 2020, dominated by aggregate and cement. Spatially, material stock distribution gaps across Chinese provinces are becoming more narrowed. Material flows wise, growing high-speed railway speed increased resource demands, but construction technology and material production advances could offset these increases. Our results demonstrate the carbon replacement value of 1008 megatons by 2020 and the operational emissions of 31 megatons annually. Compared with road and aviation passenger transport, we highlighted the environmental benefits of high-speed railway for informing green transitions

High-resolution mapping of material stocks in the built environment across 50 Chinese cities

Urban built environment stocks significantly influence the societal progression and resource consumption. Rapid urbanization has led to a near-doubling of anthropogenic mass in buildings and infrastructure every 20 years. Despite escalated energy consumption and environmental pollution, urban built environment stocks function as vital reservoirs for secondary raw materials or urban mines

Component-Level Residential Building Material Stock Characterization Using Computer Vision Techniques

Residential building material stock constitutes a significant part of the built environment, providing crucial shelter and habitat services. The hypothesis concerning stock mass and composition has garnered considerable attention over the past decade. While previous research has mainly focused on the spatial analysis of building masses, it often neglected the component-level stock analysis or where heavy labor cost for onsite survey is required. This paper presents a novel approach for efficient component-level residential building stock accounting in the United Kingdom, utilizing drive-by street view images and building footprint data. We assessed four major construction materials: brick, stone, mortar, and glass. Compared to traditional approaches that utilize surveyed material intensity data, the developed method employs automatically extracted physical dimensions of building components incorporating predicted material types to calculate material mass. This not only improves efficiency but also enhances accuracy in managing the heterogeneity of building structures. The results revealed error rates of 5 and 22% for mortar and glass mass estimations and 8 and 7% for brick and stone mass estimations, with known wall types. These findings represent significant advancements in building material stock characterization and suggest that our approach has considerable potential for further research and practical applications. Especially, our method establishes a basis for evaluating the potential of component-level material reuse, serving the objectives of a circular economy

Product and Metal Stocks Accumulation of China's Megacities: Patterns, Drivers, and Implications

The rapid urbanization in China since the 1970s has led to an exponential growth of metal stocks (MS) in use in cities. A retrospect on the quantity, quality, and patterns of these MS is a prerequisite for projecting future metal demand, identifying urban mining potentials of metals, and informing sustainable urbanization strategies. Here, we deployed a bottom up stock accounting method to estimate stocks of iron, copper, and aluminum embodied in 51 categories of products and infrastructure across 10 Chinese megacities from 1980 to 2016. We found that the MS in Chinese megacities had reached a level of 2.6-6.3 t/cap (on average 3.7 t/cap for iron, 58 kg/cap for copper, and 151 kg/cap for aluminum) in 2016, which still remained behind the level of western cities or potential saturation level on the country level (e.g., approximately 13 t/cap for iron). Economic development was identified as the most powerful driver for MS growth based on an IPAT decomposition analysis, indicating further increase in MS as China's urbanization and economic growth continues in the next decades. The latecomer cities should therefore explore a wide range of strategies, from urban planning to economy structure to regulations, for a transition toward more "metal-efficient" urbanization pathways