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Journal = Applied Sciences
Section = Ecology Science and Engineering

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22 pages, 2988 KiB  
Article
Effect of Biostimulant Formulation on Yield, Quality, and Nitrate Accumulation in Diplotaxis tenuifolia Cultivars Under Different Weather Conditions
by Alessio Vincenzo Tallarita, Rachael Simister, Lorenzo Vecchietti, Eugenio Cozzolino, Vasile Stoleru, Otilia Cristina Murariu, Roberto Maiello, Giuseppe Cozzolino, Stefania De Pascale and Gianluca Caruso
Appl. Sci. 2025, 15(15), 8620; https://doi.org/10.3390/app15158620 (registering DOI) - 4 Aug 2025
Abstract
Perennial wall rocket (Diplotaxis tenuifolia L.—DC.) exhibits genotype-dependent responses to biostimulant applications, which have not yet been deeply investigated. A two-year greenhouse factorial experiment was carried out to assess the interactions between five cultivars (Mars, Naples, Tricia, Venice, and Olivetta), three biostimulant [...] Read more.
Perennial wall rocket (Diplotaxis tenuifolia L.—DC.) exhibits genotype-dependent responses to biostimulant applications, which have not yet been deeply investigated. A two-year greenhouse factorial experiment was carried out to assess the interactions between five cultivars (Mars, Naples, Tricia, Venice, and Olivetta), three biostimulant formulations (Cystoseira tamariscifolia L. extract; a commercial legume-derived protein hydrolysate, “Dynamic”; and Spirulina platensis extract) plus an untreated control, and three crop cycles (autumn, autumn–winter, and winter) on leaf yield and dry matter, organic acids, colorimetric parameters, hydrophilic and lipophilic antioxidant activities, nitrate concentration, nitrogen use efficiency, and mineral composition, using a split plot design with three replicates. Protein hydrolysate significantly enhanced yield and nitrogen use efficiency in Mars (+26%), Naples (+25.6%), Tricia (+25%), and Olivetta (+26%) compared to the control, while Spirulina platensis increased the mentioned parameters only in Venice (+36.2%). Nitrate accumulation was reduced by biostimulant application just in Venice, indicating genotype-dependent nitrogen metabolism responses. The findings of the present research demonstrate that the biostimulant efficacy in perennial wall rocket is mainly ruled by genotypic factors, and the appropriate combinations between the two mentioned experimental factors allow for optimization of leaf yield and quality while maintaining nitrate concentration under the regulation thresholds. Full article
(This article belongs to the Section Ecology Science and Engineering)
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19 pages, 1050 KiB  
Article
Fungal Communities in Soils Contaminated with Persistent Organic Pollutants: Adaptation and Potential for Mycoremediation
by Lazaro Alexis Pedroso Guzman, Lukáš Mach, Jiřina Marešová, Jan Wipler, Petr Doležal, Jiřina Száková and Pavel Tlustoš
Appl. Sci. 2025, 15(15), 8607; https://doi.org/10.3390/app15158607 (registering DOI) - 4 Aug 2025
Abstract
The main objective of this study was to select indigenous fungal species suitable for the potential mycoremediation of the soils polluted by organic pollutants. As a sampling area, Litvínov City (North Bohemia, Czech Republic) was selected. The city is characterized by intensive coal [...] Read more.
The main objective of this study was to select indigenous fungal species suitable for the potential mycoremediation of the soils polluted by organic pollutants. As a sampling area, Litvínov City (North Bohemia, Czech Republic) was selected. The city is characterized by intensive coal mining, coal processing, and the chemical industry, predominantly petrochemistry. The elevated contents of persistent organic pollutants (POPs) such as polyaromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were identified in urban soils due to the long-term industrial pollution. The results confirmed elevated contents of PAHs in all the analyzed soil samples with high variability ranging between 0.5 and 23.3 mg/kg regardless of the position of the sampling area on the city map. PCBs and PCDD/Fs exceeded the detection limits in the soil at the sampling points, and several hotspots were revealed at some locations. All the sampling points contained a diverse community of saprotrophic and mycorrhizal fungi, as determined according to abundant basidiomycetes. Fungal species with a confirmed ability to degrade organic pollutants were found, such as species representing the genera Agaricus from the Agaricaceae family, Coprinopsis from the Psathyrellaceae family, Hymenogaster from the Hymenogasteraceae family, and Pluteus from the Pluteaceae family. These species are accustomed to particular soil conditions as well as the elevated contents of the POPs in them. Therefore, these species could be taken into account when developing potential bioremediation measures to apply in the most polluted areas, and their biodegradation ability should be elucidated in further research. The results of this study contribute to the investigation of the potential use of fungal species for mycoremediation of the areas polluted by a wide spectrum of organic pollutants. Full article
(This article belongs to the Section Ecology Science and Engineering)
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13 pages, 3189 KiB  
Article
Synthesis of Thermo-Responsive Hydrogel Stabilizer and Its Impact on the Performance of Ecological Soil
by Xiaoyan Zhou, Weihao Zhang, Peng Yuan, Zhao Liu, Jiaqiang Zhao, Yue Gu and Hongqiang Chu
Appl. Sci. 2025, 15(15), 8279; https://doi.org/10.3390/app15158279 - 25 Jul 2025
Viewed by 204
Abstract
In high-slope substrates, special requirements are imposed on sprayed ecological soil, which needs to exhibit high rheological properties before spraying and rapid curing after spraying. Traditional stabilizers are often unable to meet these demands. This study developed a thermo-responsive hydrogel stabilizer (HSZ) and [...] Read more.
In high-slope substrates, special requirements are imposed on sprayed ecological soil, which needs to exhibit high rheological properties before spraying and rapid curing after spraying. Traditional stabilizers are often unable to meet these demands. This study developed a thermo-responsive hydrogel stabilizer (HSZ) and applied it to ecological soil. The effects of HSZ on the rheological, mechanical, and vegetation performance of ecological soil were investigated, and the mechanism of the responsive carrier in the stabilizer was explored. The experimental results show that the ecological soil containing HSZ has high flowability before response, but its flowability rapidly decreases and consistency sharply increases after response. After the addition of HSZ, the 7 d unconfined compressive strength of the ecological soil reaches 1.55 MPa. The pH value of the ecological soil generally ranges from 6.5 to 8.0, and plant growth in a simulated vegetation box is favorable. Conductivity and viscosity tests demonstrate that the core–shell microcarriers, upon thermal response, release crosslinking components from the carrier, which rapidly react with the precursor solution components to form a curing system. This study provides a novel method for regulating ecological soil using a responsive stabilizer, further expanding its capacity to adapt to various complex scenarios. Full article
(This article belongs to the Section Ecology Science and Engineering)
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19 pages, 2173 KiB  
Article
The Effect of Slow-Release Fertilizer on the Growth of Garlic Sprouts and the Soil Environment
by Chunxiao Han, Zhizhi Zhang, Renlong Liu, Changyuan Tao and Xing Fan
Appl. Sci. 2025, 15(15), 8216; https://doi.org/10.3390/app15158216 - 24 Jul 2025
Viewed by 343
Abstract
To address the issue of excessive chemical fertilizer use in agricultural production, this study conducted a pot experiment with four treatments: CK (no fertilization), T1 (the application of potassium magnesium sulfate fertilizer), T2 (the application of slow-release fertilizer equal to T1), and T3 [...] Read more.
To address the issue of excessive chemical fertilizer use in agricultural production, this study conducted a pot experiment with four treatments: CK (no fertilization), T1 (the application of potassium magnesium sulfate fertilizer), T2 (the application of slow-release fertilizer equal to T1), and T3 (the application of slow-release fertilizer with the same fertility as T1). The effects of these treatments on garlic seedling yield, growth quality, chlorophyll content, photosynthetic characteristics, and the soil environment were investigated to evaluate the feasibility of replacing conventional fertilizers with slow-release formulations. The results showed that compared with CK, all three fertilized treatments (T1, T2, and T3) significantly increased the plant heights and stem diameters of the garlic sprouts (p < 0.05). Plant height increased by 14.85%, 17.81%, and 27.75%, while stem diameter increased by 9.36%, 8.83%, and 13.96%, respectively. Additionally, the chlorophyll content increased by 4.34%, 7.22%, and 8.05% across T1, T2, and T3, respectively. Among the treatments, T3 exhibited the best overall growth performance. Compared with those in the CK group, the contents of soluble sugars, soluble proteins, free amino acids, vitamin C, and allicin increased by 64.74%, 112.17%, 126.82%, 36.15%, and 45.43%, respectively. Furthermore, soil organic matter, available potassium, magnesium, and phosphorus increased by 109.02%, 886.25%, 91.65%, and 103.14%, respectively. The principal component analysis indicated that soil pH and exchangeable magnesium were representative indicators reflecting the differences in the soil’s chemical properties under different fertilization treatments. Compared with the CK group, the metal contents in the T1 group slightly increased, while those in T2 and T3 generally decreased, suggesting that the application of slow-release fertilizer exerts a certain remediation effect on soils contaminated with heavy metals. This may be attributed to the chemical precipitation and ion exchange capacities of phosphogypsum, as well as the high adsorption and cation exchange capacity of bentonite, which help reduce the leaching of soil metal ions. In summary, slow-release fertilizers not only promote garlic sprout growth but also enhance soil quality by regulating its chemical properties. Full article
(This article belongs to the Section Ecology Science and Engineering)
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22 pages, 3650 KiB  
Article
Seasonal Biochemical Variations in Mediterranean Halophytes and Salt-Tolerant Plants: Targeting Sustainable Innovations in Ruminant Health
by Marta Oliveira, Catarina Guerreiro Pereira, Viana Castañeda-Loaiza, Maria João Rodrigues, Nuno R. Neng, Hervé Hoste, Karim Ben Hamed and Luísa Custódio
Appl. Sci. 2025, 15(14), 7625; https://doi.org/10.3390/app15147625 - 8 Jul 2025
Viewed by 474
Abstract
Climate change intensifies water scarcity and soil salinization, threatening agriculture and livestock systems, especially in arid Mediterranean regions. Halophytes and salt-tolerant plants offer sustainable alternatives to support ruminant health and productivity where traditional crops fail, helping mitigate climate impacts. This work evaluated seasonality [...] Read more.
Climate change intensifies water scarcity and soil salinization, threatening agriculture and livestock systems, especially in arid Mediterranean regions. Halophytes and salt-tolerant plants offer sustainable alternatives to support ruminant health and productivity where traditional crops fail, helping mitigate climate impacts. This work evaluated seasonality effects on the biochemical properties, including proximate composition, minerals, antioxidant properties, and the phenolic composition of the aerial organs of halophytes and salt-tolerant species, aiming at their future exploitation in ruminant production as novel nutraceutical or phytotherapeutic products. Target species included four halophytic species according to the eHaloph database (Calystegia soldanella (L.) R. Br. 1810, Medicago marina L. 1753, Plantago coronopus L. 1753, and Limoniastrum monopetalum (L.) Boiss. 1848) and five salt-tolerant plants (Pistacia lentiscus L. 1753, Cladium mariscus (L.) Pohl 1809, Inula crithmoides L. (syn. Limbarda crithmoides Dumort. 1827), Helichrysum italicum subsp. picardii (Boiss. & Reut.) Franco 1984, and Crucianella maritima L. 1753). H. italicum, M. marina, and C. soldanella appear well-suited for nutraceutical applications, while P. lentiscus, L. monopetalum, and C. mariscus hold promise for the development of, for example, phytotherapeutic products. This research underscores the significance of seasonal and species-specific variations in nutrient and phytochemical composition, displaying a range of opportunities for novel, sustainable, and tailored solutions to ruminant production systems in arid environments. Full article
(This article belongs to the Special Issue Recent Advances in Halophytes Plants)
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20 pages, 9084 KiB  
Article
Geochemical Assessment of Potentially Toxic Elements in Urban Stream Sediments Draining into the Keban Dam Lake, Turkey
by Hatice Kara
Appl. Sci. 2025, 15(13), 7565; https://doi.org/10.3390/app15137565 - 5 Jul 2025
Viewed by 226
Abstract
The present study investigates the extent and spatial distribution of metal concentration in stream sediments that flow into Keban Dam Lake, Turkey. Sediment samples were analysed for trace and potentially toxic elements (PTEs), including V, Cr, Co, Ni, Cu, Zn, Pb, Tl, Th, [...] Read more.
The present study investigates the extent and spatial distribution of metal concentration in stream sediments that flow into Keban Dam Lake, Turkey. Sediment samples were analysed for trace and potentially toxic elements (PTEs), including V, Cr, Co, Ni, Cu, Zn, Pb, Tl, Th, and U. Enrichment Factor (EF), Contamination Factor (CF), Geo-accumulation Index (Igeo), and Pollution Load Index (PLI) were employed to assess contamination levels. Results reveal that Cr exhibited very high enrichment (EF = 15.95) in downstream urban samples, while Cu and Zn showed high enrichment in samples collected from the middle to lower reaches of the stream, probably indicating anthropogenic contributions. Most other elements, such as Pb, Tl, Th, and U, were within natural background levels. Sediment Quality Guidelines (SQGs) indicate that Cr, Ni, and Cu may pose potential ecological risks, especially in samples from urban-influenced and downstream areas where concentrations exceed the Probable Effect Levels (PEL; Cr: 160 mg/kg, Ni: 42.8 mg/kg, Cu: 108 mg/kg). Multivariate statistical analyses, including Pearson correlation and hierarchical clustering, reveal three distinct geochemical groupings. Among these, the most contaminated cluster—corresponding to midstream and downstream regions—is characterized by elevated Cu and Zn concentrations. Strong correlations among Cu–Zn, Ni–Cu, and Th–U suggest there is a combination of anthropogenic and lithogenic sources for most metals. While most sites showed low to moderate pollution, urban downstream locations exhibited significant metal accumulation, necessitating the region’s continued environmental monitoring and management strategies. Full article
(This article belongs to the Special Issue Ecotoxicology of Trace Elements on Ecosystems)
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20 pages, 1230 KiB  
Article
The Evolutionary Traits of Carbon Emissions from the Planting Industry in Beijing, China
by Limin Chuan, Hui Zhang, Jiang Zhao, Jingjuan Zhao and Ailing Wang
Appl. Sci. 2025, 15(13), 7535; https://doi.org/10.3390/app15137535 - 4 Jul 2025
Viewed by 210
Abstract
Making clear the exact amount of carbon emissions from the planting industry is of great significance for developing low-carbon agriculture and helping achieve carbon neutrality. The current carbon emissions from the planting industry in Beijing, the capital of China, are still unclear, and [...] Read more.
Making clear the exact amount of carbon emissions from the planting industry is of great significance for developing low-carbon agriculture and helping achieve carbon neutrality. The current carbon emissions from the planting industry in Beijing, the capital of China, are still unclear, and there is a lack of quantitative research on the production, economic, and ecological benefits of carbon emissions. This paper used the carbon emissions factor method to study the inter-annual variation characteristics of carbon emissions and carbon benefits in Beijing’s planting industry since 2000. The results show that the carbon emissions from the planting industry in Beijing in 2023 were 256,400 tons, of which the carbon emissions from agricultural inputs, nitrous oxide (N2O) from farmland, and methane (CH4) from rice cultivation were 149,300, 105,200, and 2000 tons, respectively. From 2000 to 2023, the total carbon emissions from the planting industry in Beijing have shown a downward trend. Compared with 2000, the carbon emissions from agricultural inputs and N2O in 2023 decreased by 59.88% and 74.52%, respectively. The carbon emissions of CH4 from rice cultivation were only 2.38% of those in 2000, and the total carbon emissions from the planting industry in Beijing decreased by 70.43%. The average carbon emissions from agricultural inputs and N2O accounted for 50.85% and 47.95% of the total level of the planting industry, respectively, and were the main sources of carbon emissions in Beijing. Chemical fertilizer and agricultural film inputs were important sources of carbon emissions from agricultural inputs. Reducing inputs for agriculture and sources of N2O from farmland is an important way to reduce carbon emissions from agriculture in Beijing. In the end, some suggestions were proposed for reducing carbon emissions from the planting industry. Full article
(This article belongs to the Section Ecology Science and Engineering)
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27 pages, 2707 KiB  
Systematic Review
The Role of Trees in Sand Dune Rehabilitation: Insights from Global Experiences
by Lucian Dinca, Aurora Coca, Nicu Constantin Tudose, Mirabela Marin, Gabriel Murariu and Dan Munteanu
Appl. Sci. 2025, 15(13), 7358; https://doi.org/10.3390/app15137358 - 30 Jun 2025
Viewed by 383
Abstract
The present review summarizes the existing knowledge regarding the afforestation of sand dunes. Our main focus was on the role of trees in stabilizing and rehabilitating these complex ecosystems. We analyzed 937 publications through a systematic bibliometric review and then proceeded to select [...] Read more.
The present review summarizes the existing knowledge regarding the afforestation of sand dunes. Our main focus was on the role of trees in stabilizing and rehabilitating these complex ecosystems. We analyzed 937 publications through a systematic bibliometric review and then proceeded to select 422 articles that met our criteria. This methodological approach—combining a comprehensive bibliometric analysis with an in-depth traditional literature review—represents a novel contribution to the field and allows for both quantitative trends and qualitative insights to be captured. This was then complemented by an in-depth literature review. Our results sustain the global importance of this subject, as they include studies from more than 80 countries, with a focus on the USA, China, Australia, and Japan. We have also identified a series of main tree species that are usually used in the afforestation of sand dunes (Pinus, Acacia, Juniperus) and then proceeded to analyze their ecologic and socio-economic impact. As such, we have analyzed case studies from all continents, showcasing a variety of strategies that were successful and adapted to local conditions. This did not exclude challenges, mainly invasive species, low survival rates, and effects on biodiversity and stabilization. The main factors that impact the success of afforestation are represented by topography, soil structure, water dynamics, and climate. Unlike previous reviews, this study offers a global synthesis of both the scientific output and the applied outcomes of sand dune afforestation, bridging the gap between research and practice. As such, afforestation has a positive impact on soil fertility and carbon sequestration but can also present a major risk to native ecosystems. In this context, the present review highlights the need to adopt strategies that are unique for that site, and that must integrate all aspects (ecological, social, economic) to ensure good results. Our ISI-indexed literature review helped us to address the link between the current knowledge, research trends, and future topics that must be addressed. Full article
(This article belongs to the Special Issue Ecosystems and Landscape Ecology)
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18 pages, 2863 KiB  
Article
Evolution of Microbial Community Structure and Denitrifying Functional Microorganisms in the Biological Sponge Iron System
by Jing Li, Huina Xie, Wei Zhao and Jie Li
Appl. Sci. 2025, 15(13), 7244; https://doi.org/10.3390/app15137244 - 27 Jun 2025
Viewed by 307
Abstract
With the growing problem of global water pollution, nitrogen pollution has become a key factor affecting aquatic ecosystems and human health. The biological sponge iron system (BSIS) has gained attention as a research hotspot due to its efficient denitrification capability. This study focused [...] Read more.
With the growing problem of global water pollution, nitrogen pollution has become a key factor affecting aquatic ecosystems and human health. The biological sponge iron system (BSIS) has gained attention as a research hotspot due to its efficient denitrification capability. This study focused on the changes in microbial community structure and the relative abundance and interrelationships of nitrogen cycle-related functional bacteria at different operational stages of the BSIS with a sponge iron (SFe) dosage of 90 g/L. The results showed that as the operation time of the reactor extended, the relative abundance of denitrifying genera such as Saccharimonadales, Arenimonas, and Acinetobacter significantly increased, while the relative abundance of Proteobacteria showed a trend of initial increase followed by a decrease. The relative abundance of nitrifying bacteria exhibited a more complex variation, whereas the abundance of denitrifying bacteria showed a continuous upward trend. In addition, there were complex interrelationships among different denitrifying bacteria, such as a positive correlation between Saccharimonadales and Acetobacteraceae, and a negative correlation between Rhodothermus and Pseudoxanthomonas. This study not only revealed the changes in the relative abundance and interrelationships of microbial communities and nitrogen cycle-related functional bacteria over time with an SFe dosage of 90 g/L, but also provided a new perspective for understanding the intrinsic mechanism of enhanced biological denitrification by sponge iron. These findings are of great significance for optimizing the operating parameters of the BSIS, improving denitrification efficiency, and promoting the practical application of this technology in the field of environmental engineering. Full article
(This article belongs to the Section Ecology Science and Engineering)
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15 pages, 2670 KiB  
Article
Empirical Study on Failure Prediction of Rotating Biological Contactors Available for Landfill Site Operators: Scoring Analysis Based on 17-Year Daily Inspection Reports
by Hiroyuki Ishimori, Yugo Isobe, Tomonori Ishigaki and Masato Yamada
Appl. Sci. 2025, 15(13), 6950; https://doi.org/10.3390/app15136950 - 20 Jun 2025
Viewed by 312
Abstract
This study proposes a practical method for the early detection of failure signs in a rotating biological contactor (RBC) system that has been in long-term operation at a municipal solid waste landfill. Seventeen years of inspection logs, recorded between 2006 and 2023, were [...] Read more.
This study proposes a practical method for the early detection of failure signs in a rotating biological contactor (RBC) system that has been in long-term operation at a municipal solid waste landfill. Seventeen years of inspection logs, recorded between 2006 and 2023, were digitized and analyzed with a focus on abnormal noise, electric current values, operational status, and failure history. The analysis revealed that frequent occurrences of abnormal noise and sudden fluctuations in current tend to precede equipment failures. Based on these findings, we developed a scoring model for the predictive maintenance of RBCs. Traditionally, determining the score required professional knowledge such as performing a sensitivity analysis. However, by utilizing AI (ChatGPT o4), we were able to obtain recommended values for these parameters. This means that operators can now build and adjust a scoring model for predictive maintenance of RBCs according to their specific on-site conditions. On the other hand, sudden increases in current and abnormal noises were previously considered strong indicators of failure prediction. These parameters will depend on factors such as the sensitivity of electrical current meters and surrounding noise. Therefore, depending on the specific environmental conditions at the site, the scoring model developed in this study may have limited predictive accuracy. Full article
(This article belongs to the Section Ecology Science and Engineering)
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15 pages, 4753 KiB  
Article
Continuous Electrical Resistivity Tomography Monitoring in Waste Landfill Sites with Different Properties and Visualization of Water Channels
by Yugo Isobe and Hiroyuki Ishimori
Appl. Sci. 2025, 15(12), 6920; https://doi.org/10.3390/app15126920 - 19 Jun 2025
Cited by 1 | Viewed by 450
Abstract
This study aims to obtain findings on the internal water behavior, the presence of water channels, and the degree of washout due to rainfall infiltration in Japanese municipal solid waste (MSW) final disposal sites. Electrical resistivity tomography (ERT) monitoring and undistributed waste sampling [...] Read more.
This study aims to obtain findings on the internal water behavior, the presence of water channels, and the degree of washout due to rainfall infiltration in Japanese municipal solid waste (MSW) final disposal sites. Electrical resistivity tomography (ERT) monitoring and undistributed waste sampling for X-ray computed tomography (X-ray CT) analysis were conducted in the field. The study sites were targeted at Site A, which is mainly composed of non-combustible residues, and Site B, which is mainly composed of incineration ash. The time-dependent resistivity distributions obtained from real-time ERT monitoring were effective for us to understand the water content distribution after water infiltration during water injection tests. As a result, the global flow behavior and the local water channel flow were determined. In addition, X-ray CT analysis of the undisturbed waste samples obtained from the sites clarified the different pore structures, indicating the possibility of more advanced washing out at Site A than at Site B. Furthermore, the soil cover layer and gas extraction wells had a significant effect on the resistivity structure with respect to water flow behavior. Since soil cover layer and gas extraction wells are significant factors affecting waste stabilization by washout, it is suggested that these factors should be considered in the design and maintenance of landfills. Full article
(This article belongs to the Special Issue Advanced Technologies in Landfills)
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8 pages, 2357 KiB  
Article
Net Ecosystem Exchanges of Spruce Forest Carbon Dioxide Fluxes in Two Consecutive Years in Qilian Mountains
by Bingying Qiao, Lili Sheng, Kelong Chen and Yangong Du
Appl. Sci. 2025, 15(12), 6845; https://doi.org/10.3390/app15126845 - 18 Jun 2025
Viewed by 210
Abstract
The net ecosystem CO2 exchange (NEE) of spruce forest ecosystems is poorly understood by the lack of measurements of CO2 in the Qilian Mountain of Western China. Thus, we conducted consecutive measurements of CO2 fluxes using tower-based the eddy covariance [...] Read more.
The net ecosystem CO2 exchange (NEE) of spruce forest ecosystems is poorly understood by the lack of measurements of CO2 in the Qilian Mountain of Western China. Thus, we conducted consecutive measurements of CO2 fluxes using tower-based the eddy covariance method from 2021 to 2022. These results indicated that daily NEE of spruce forest indicated a robust temporal pattern ranging from −28.43 to 29.62 g C m−2 from 2021 to 2022. Remarkable carbon sink characteristics were presented from late May to late September. Month accumulative NEE fluxes ranged from −336.57 to 142.22 g C m−2 in two years. Additionally, average carbon sink was 591.51 ± 37.41 g C m−2 in Qilian Mountain. NEE was negatively driven by vapor pressure deficit (VPD) and average air temperature (p < 0.05), as determined using the structural equation model. However, the direct effect coefficient of precipitation on NEE was weak. VPD was positively driven by air temperature and negatively determined by precipitation. In conclusion, a future warming scenario would significantly decrease the carbon sink of the spruce forest in Qilian Mountain. Full article
(This article belongs to the Section Ecology Science and Engineering)
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18 pages, 3910 KiB  
Article
Simulation-Based Assessment of Urban Pollution in Almaty: Influence of Meteorological and Environmental Parameters
by Lyazat Naizabayeva, Kateryna Kolesnikova and Victoriia Khrutba
Appl. Sci. 2025, 15(12), 6391; https://doi.org/10.3390/app15126391 - 6 Jun 2025
Viewed by 473
Abstract
Background: Air pollution is a persistent and critical challenge for Almaty, Kazakhstan’s largest city. The city’s unique topographical and meteorological conditions—being located in a mountain basin with dense urban development—restrict natural ventilation and contribute to frequent exceedances of air quality standards. These factors [...] Read more.
Background: Air pollution is a persistent and critical challenge for Almaty, Kazakhstan’s largest city. The city’s unique topographical and meteorological conditions—being located in a mountain basin with dense urban development—restrict natural ventilation and contribute to frequent exceedances of air quality standards. These factors make accurate assessment and management of atmospheric pollution particularly urgent for the region. Aim: This study aims to develop and apply a novel, high-resolution three-dimensional numerical model to analyze the spatial distribution of key atmospheric indicators—air velocity, temperature, and pollutant concentrations in Almaty. The goal is to provide a comprehensive understanding of how meteorological and urban factors influence air quality, with a focus on both horizontal and vertical stratification. Methods: A three-dimensional computational model was constructed, integrating real meteorological data and detailed urban topography. The model solves the compressible Navier–Stokes, energy, and pollutant transport equations using the finite volume method over a 1000 × 1000 × 500 m domain. Meteorological fields are synthesized along all spatial axes to account for vortex structures, urban heat islands, and stratification effects. This approach enables the simulation of atmospheric parameters with unprecedented spatial resolution for Almaty. Results: The simulation reveals significant spatial heterogeneity in atmospheric parameters. Wind velocity ranges from 0.31 to 5.76 m/s (mean: 2.14 m/s), temperature varies between 12.03 °C and 19.47 °C (mean: 16.12 °C), and pollutant concentrations fluctuate from 5.02 to 102.35 μg/m3 (mean: 44.87 μg/m3). Notably, pollutant levels in the city center exceed those at the periphery by more than two-fold (68.23 μg/m3, 29.14 μg/m3), and vertical stratification leads to a marked decrease in concentrations with altitude. These findings provide, for the first time, a comprehensive and quantitative picture of air quality dynamics in Almaty. Conclusion: The developed model advances the scientific understanding of urban air pollution in complex terrains and offers practical tools for city planners and policymakers. By identifying pollution hotspots and elucidating the influence of meteorological factors, the model supports the optimization of urban infrastructure, zoning, and environmental monitoring systems. This research lays the groundwork for evidence-based strategies to mitigate air pollution and improve public health in Almaty and similar urban environments. Full article
(This article belongs to the Section Ecology Science and Engineering)
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35 pages, 2642 KiB  
Review
Targeted Acidogenic Fermentation of Waste Streams for the Selective Production of Volatile Fatty Acids as Bioplastic Precursors
by Dolores Hidalgo, Lidia Garrote, Francisco Infante, Jesús M. Martín-Marroquín, Enrique Pérez-Zapatero and Francisco Corona
Appl. Sci. 2025, 15(11), 5923; https://doi.org/10.3390/app15115923 - 24 May 2025
Viewed by 630
Abstract
The sustainable production of bioplastics is increasingly important for reducing reliance on fossil fuels and addressing environmental challenges. The acidogenic fermentation of waste streams offers a promising pathway for generating key bioplastic precursors, such as volatile fatty acids, which can be used to [...] Read more.
The sustainable production of bioplastics is increasingly important for reducing reliance on fossil fuels and addressing environmental challenges. The acidogenic fermentation of waste streams offers a promising pathway for generating key bioplastic precursors, such as volatile fatty acids, which can be used to produce polymers like polyhydroxyalkanoates. This review explores the potential of various waste streams, including agricultural residues, industrial by-products, and food waste, as substrates for acidogenic fermentation, aligning with circular economy principles by reducing waste and environmental impact. A key feature of this review is its focus on targeted acidogenic fermentation, which optimizes process conditions to maximize the production of specific acids based on waste characteristics. The analysis emphasizes how the chemical composition and biodegradability of waste streams influence the selection of microbial consortia and metabolic pathways, determining the yield and composition of the products generated. The review also highlights the adaptability of acidogenic fermentation to heterogeneous and variable waste streams, underlining its potential as a scalable and sustainable solution for bioplastic precursor production. By tailoring process parameters such as pH and hydraulic retention time to the specific characteristics of the substrate, targeted acidogenic fermentation can effectively transform waste into high-value intermediates. Finally, challenges related to the scalability and economic feasibility of these processes are discussed, along with opportunities for integrating acidogenic fermentation with complementary waste valorization technologies to advance the bio-based economy. The findings underscore the critical role of waste streams in enabling the sustainable and efficient generation of bioplastic precursors, contributing to a circular economy framework. Full article
(This article belongs to the Section Ecology Science and Engineering)
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14 pages, 2915 KiB  
Article
An Integrated DEM–FEM Simulation Framework for Preferential Flow Path Evaluation in Waste Landfill Composed of Non-Spherical Particles
by Hiroyuki Ishimori, Kazuto Endo and Masato Yamada
Appl. Sci. 2025, 15(11), 5798; https://doi.org/10.3390/app15115798 - 22 May 2025
Viewed by 326
Abstract
A numerical experimental method combining the discrete element method (DEM) and the finite element method (FEM) is proposed to analyze water channel flow in heterogeneous porous media such as landfill layers. In this study, non-spherical particles —thin plates and rods—are introduced into DEM-FEM [...] Read more.
A numerical experimental method combining the discrete element method (DEM) and the finite element method (FEM) is proposed to analyze water channel flow in heterogeneous porous media such as landfill layers. In this study, non-spherical particles —thin plates and rods—are introduced into DEM-FEM coupling for the first time, which allows for the virtual reconstruction of complex pore structures beyond the capability of traditional experimental approaches, such as soil tanks or X-ray CT. Fluid flow simulations performed on three types of virtual porous media showed that only the case with non-spherical particles generated water channels. Tortuosity analysis was used to quantify the complexity of the flow paths and showed median values of 1.258 and 1.218 for homogeneous and particle size-distributed cases, respectively. In contrast, the case simulating waste media had a significantly lower median tortuosity of 1.051, with a skewed distribution toward shorter paths, indicating dominant water channels. This shift in tortuosity, coupled with higher variance, serves as quantitative evidence of water channel formation. The results demonstrate that tortuosity analysis complements streamline visualization and provides a reliable means to detect and compare water channel flow behavior. The proposed DEM-FEM framework enables both qualitative and quantitative understanding of flow dynamics in large-scale, highly heterogeneous porous systems and is expected to support further research and practical design in landfill and drainage engineering. Full article
(This article belongs to the Special Issue Advanced Technologies in Landfills)
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