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1.
Environ Monit Assess ; 192(11): 674, 2020 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-33011837

RESUMO

Prediction of dissolved organic carbon (DOC) based on catchment characteristics is a useful tool for efficient and effective water management, but in the case of arid and semi-arid regions, such predictive capacity is scarce. Accordingly, the main objective of this study was to evaluate the significance of principal components for predicting DOC concentrations and fluxes in nine headwater catchments of the Hiv catchment located in the Southern Alborz Mountains in the west of Tehran, Iran. To achieve this aim, data were assembled on 24 headwater catchment characteristics comprising soil properties, physiography, seasonal rainfall, and flow attributes, as well as estimates of DOC concentrations and fluxes across four seasons. The results revealed a major positive correlation between DOC and soil organic matter parameters related to soil biological processes. Using general linear modelling, an organic matter component related to soil biology, a seasonal component related to the dummy effect of sampling seasons, and a soil physical component related to soil texture were found to be the best predictors for DOC responses in the study area.


Assuntos
Ciclo do Carbono , Monitoramento Ambiental , Carbono/análise , Irã (Geográfico) , Solo
2.
J Environ Qual ; 49(2): 460-471, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33016418

RESUMO

The agricultural reuse of urban sewage sludge (USS) modifies soil properties depending on sludge quality, management, and pedo-environmental conditions. The aim of this microcosm study was to assess C mineralization and subsequent changes in soil properties after USS addition to two typical Mediterranean soils: sandy (Soil S) and sandy loam (Soil A) at equivalent field rates of 40 t ha-1 (USS-40) and 120 t ha-1 (USS-120). Outcomes proved the biodegradability of USS through immediate CO2 release inside incubation bottles in a dose-dependent manner. Accordingly, the highest rates of daily C emission were recorded with USS-120 (3.7 and 3.9 mg kg-1 d-1 for Soils S and A, respectively) after 84 d of incubation at 25 °C. The addition of USS also improved soil fertility by enhancing soil macronutrients, microbial proliferation, and protease activity. Protease showed significant correlation with N, total organic C, and heterotrophic bacteria, reflecting the biostimulation and bioaugmentation effects of sludge. Soil indices like C/N/P stoichiometry and metabolic quotient (qCO2 ) varied mostly with mineralization rates of C and P in both soils. Despite a significant increase of soil salinity and total heavy metal content (lead, nickel, zinc, and copper) with USS dose, wheat germination was not affected by these changes. Both experimental soils showed intrinsic (Soil A) and incubation-induced (Soil S) phytotoxicities that were alleviated by USS addition. This was likely due to the enhancement of biodegradation and/or retention of phytotoxicants originating from previous land uses. Urban sewage sludge amendments could have applications in soil remediation by reducing the negative effects of allelopathic and/or anthropogenic phytoinhibitors.


Assuntos
Poluentes do Solo/análise , Poluentes do Solo/toxicidade , Solo , Carbono/análise , Biomarcadores Ambientais , Esgotos
3.
J Environ Sci (China) ; 97: 149-161, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32933730

RESUMO

Transboundary and domestic aerosol transport during 2018-2019 affecting Bangkok air quality has been investigated. Physicochemical characteristics of size-segregated ambient particles down to nano-particles collected during 2017 non-haze and 2018-2019 haze periods were analyzed. The average PM2.5 concentrations at KU and KMUTNB sites in Bangkok, Thailand during the haze periods were about 4 times higher than in non-haze periods. The highest average organic carbon and elemental carbon concentrations were 4.6 ± 2.1 µg/m3 and 1.0 ± 0.4 µg/m3, respectively, in PM0.5-1.0 range at KU site. The values of OC/EC and char-EC/soot-EC ratios in accumulation mode particles suggested the significant influence of biomass burning, while the nuclei and coarse mode particles were from mixed sources. PAH concentrations during 2018-2019 haze period at KU and KMUTNB were 3.4 ± 0.9 ng/m3 and 1.8 ± 0.2 ng/m3, respectively. The PAH diagnostic ratio of PM2.5 also suggested the main contributions were from biomass combustion. This is supported by the 48-hrs backward trajectory simulation. The higher PM2.5 concentrations during 2018-2019 haze period are also associated with the meteorological conditions that induce thermal inversions and weak winds in the morning and evening. Average values of benzo(a)pyrene toxic equivalency quotient during haze period were about 3-6 times higher than during non-haze period. This should raise a concern of potential human health risk in Bangkok and vicinity exposing to fine and ultrafine particulate matters in addition to regular exposure to traffic emission.


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar , Aerossóis/análise , Biomassa , Carbono/análise , Monitoramento Ambiental , Humanos , Tamanho da Partícula , Material Particulado/análise , Estações do Ano , Tailândia
4.
J Environ Manage ; 275: 111221, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32956918

RESUMO

Accurately assessing the effectiveness of industrial carbon emission reduction in each province and optimizing the emission reduction path have important practical significance for China's Nationally Determined Contribution (NDC) emission reduction achievement targets. This study first evaluates the industry's emission reduction effects across 30 provinces of China. Then, the emission reduction paths of "lagging regions," which fail to meet the 2030 industrial carbon emission reduction target, are optimized based on the two-dimensional perspective of carbon emission efficiency and emission reduction cost. This study found that (1) China has exceeded its 2020 industrial carbon emission reduction target. There are 9 potential "lagging regions" that failed to meet their 2020 targets, (2) if the current emission reduction rate is maintained, China is capable of exceeding its 2030 industrial carbon emission reduction target, but there are still 11 "lagging regions," (3) there are clear differences in carbon emission efficiency and shadow price among the "lagging regions," and (4) under the premise of ensuring feasibility and fairness, the three provinces of Liaoning, Guangxi, and Shaanxi can set strict emission reduction targets, while other "lagging regions" can set flexible targets.


Assuntos
Carbono , Indústrias , Carbono/análise , Dióxido de Carbono/análise , China , Custos e Análise de Custo
5.
Nat Commun ; 11(1): 4897, 2020 09 29.
Artigo em Inglês | MEDLINE | ID: mdl-32994415

RESUMO

Soil microbial respiration is an important source of uncertainty in projecting future climate and carbon (C) cycle feedbacks. However, its feedbacks to climate warming and underlying microbial mechanisms are still poorly understood. Here we show that the temperature sensitivity of soil microbial respiration (Q10) in a temperate grassland ecosystem persistently decreases by 12.0 ± 3.7% across 7 years of warming. Also, the shifts of microbial communities play critical roles in regulating thermal adaptation of soil respiration. Incorporating microbial functional gene abundance data into a microbially-enabled ecosystem model significantly improves the modeling performance of soil microbial respiration by 5-19%, and reduces model parametric uncertainty by 55-71%. In addition, modeling analyses show that the microbial thermal adaptation can lead to considerably less heterotrophic respiration (11.6 ± 7.5%), and hence less soil C loss. If such microbially mediated dampening effects occur generally across different spatial and temporal scales, the potential positive feedback of soil microbial respiration in response to climate warming may be less than previously predicted.


Assuntos
Carbono/análise , Metagenoma/genética , Microbiota/fisiologia , Microbiologia do Solo , Solo/química , Aclimatação/genética , Archaea/genética , Archaea/isolamento & purificação , Archaea/metabolismo , Bactérias/genética , Bactérias/isolamento & purificação , Bactérias/metabolismo , Carbono/metabolismo , Ciclo do Carbono , Celulose/metabolismo , DNA Ambiental/genética , DNA Ambiental/isolamento & purificação , Fungos/genética , Fungos/isolamento & purificação , Fungos/metabolismo , Aquecimento Global , Pradaria , Temperatura Alta/efeitos adversos , Metagenômica , Modelos Genéticos , Raízes de Plantas/química , Poaceae/química
6.
Mar Pollut Bull ; 158: 111412, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32753196

RESUMO

The Conwy estuary was evaluated for sediment quality. Microtox bioassay revealed 38 of 39 sites were non-toxic. Hg ranged from 0.001 to 0.153 µg kg-1, mean 0.026 mg kg-1, Σ16 PAH from 18 to 1578 µg kg-1, mean 269 µg kg-1, Σ22 PAH, 18 to 1871 µg kg-1 mean to 312 µg kg-1, two sites had high perylene relative to ΣPAH. Σ22PAH correlated positively with TOC, clay and silt (R2 0.89, 0.92, 0.90) and negatively with sand. Multivariate statistics, delineated four spatial (site) and five variable (measurements) clusters. Spatial clustering relates to sediment grain size, in response to hydrodynamic processes in estuary; fine (clay to silt) sized sediments exhibit the highest Hg and PAH content, because these components partitioned into the fine fraction. Comparison to national and international environmental standards suggests Hg and PAH content of Conwy sediments are unlikely to harm ecology or transfer up into the human food chain.


Assuntos
Mercúrio/análise , Poluentes Químicos da Água/análise , Carbono/análise , Monitoramento Ambiental , Estuários , Sedimentos Geológicos , Humanos , Rios , Reino Unido , País de Gales
7.
J Environ Manage ; 271: 110895, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32778257

RESUMO

Effective strategies, policies and measures for carbon emission reduction need to be developed and implemented according to good understanding of both local conditions and spatial differentiation mechanism of energy consumption associated with human activities at high resolution. In the study, we first collected statistical yearbooks, high resolution remotely sensed imageries, and 3895 usable questionnaires for the urban areas of Kaifeng; then measured the carbon emissions from household energy consumption, using the accounting method provided in the IPCC GHG Inventory Guidelines; and finally applied both exploratory and explanatory statistical methods to characterize the spatial pattern of carbon emissions at high resolution, identify key influencing factors, and gain better understanding of the spatial differentiation mechanism of urban residential carbon emissions. Our study reached the following conclusions: (1) Central heating facilities with controllable flow are important for carbon emissions reduction, but its spatial distribution shows unfairness; (2) Spatial clusters of high carbon emission areas were primarily located in the outer suburbs of the city, validated to some extent the hypothesis that urban sprawl has a driving effect on the increasing urban residential carbon emissions; (3) Factors like size of residential area, family structure, life style, personal preference and behavior rather than household income have significant impacts on household carbon emissions, implying that effective control of residential areas, promotion of family life and low-carbon lifestyle, and effective guidance of proper behaviors and preferences will play a crucial role in reducing urban residential carbon emissions; and (4) Most of the identified influencing factors exhibit clear and specific spatial patterns and gradients of impact, implying that measures for urban residential carbon emission reduction should be adapted to location conditions. The study has generated a set of concrete evidences and improved understandings of the spatially differentiated mechanisms upon which the formation and deployment of any effective strategies, policies and measures for reducing urban residential carbon emissions should be based.


Assuntos
Dióxido de Carbono/análise , Carbono/análise , China , Cidades , Calefação , Humanos
8.
Environ Monit Assess ; 192(9): 571, 2020 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-32772191

RESUMO

Forests hold significant potential for carbon sequestration and climate change mitigation. Forest biomass estimation is vital for sustainable forest management, providing critical input data for implementing the United Nations Reducing Emissions from Deforestation and forest Degradation-plus (REDD+) mechanism. This study investigates the total carbon pools-aboveground biomass (AGB), belowground biomass (BGB), forest floor biomass, and soil carbon-using field-based information in the muyong forest management system, which is native to Ifugao in the Philippines. This study reveals that a difference may be observed between the total carbon stock of the private woodlots (muyong) and that of the communal forest (bilid). The results indicate that the bilid forest has trees with a small diameter at breast height (DBH) and high tree density in contrast to the muyong, which has trees with high DBH and low tree density. The average carbon stock per unit area is higher in muyong (150.8 tC/ha) than in bilid (126.1 tC/ha). These findings are valuable in determining whether Ifugao's muyong forest system should be included under the REDD+ framework. Human mediation and management helps forests to sequester a greater amount of carbon than they would without human intervention. Implementation of REDD+ should promote Ifugao's ecosystem and biodiversity conservation and agroforestry practices in addition to protecting traditional agricultural practices and livelihoods in relation to rice terraces.


Assuntos
Carbono/análise , Ecossistema , Conservação dos Recursos Naturais , Monitoramento Ambiental , Florestas , Filipinas
9.
Sci Total Environ ; 737: 140299, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32783867

RESUMO

Fine roots (≤2 mm in diameter) play a more significant role in regulating the biogeochemical cycles of forest ecosystems, but our current knowledge of fine root stoichiometry and its driving factors is extremely limited. In this study, fine root biomass (FRB) and their carbon (C), nitrogen (N) and phosphorus (P) concentrations were measured from dominant forests along environmental gradients in Northwestern China. The results showed that forest type (coniferous vs. broadleaved, and plantation vs. secondary forest) and climatic factors had no effects on FRB. FRB was only correlated with soil P, C:P and N:P in coniferous forests and N:P in secondary forests. Thus, forest type, soil C:N:P stoichiometry and climatic factors were less important to FRB. The fine root C and C:N and C:P were higher, and N and P were lower in coniferous than in broadleaved forests. Only fine root N concentration was higher in plantations than in secondary forests. The fine root C was positively correlated with soil C, N and C:N, C:P and N:P except in coniferous forests. The fine root N was negatively correlated soil C:N, C:P and N:P in plantations and C:N in broadleaved forests, but positively correlated with soil C, N, C:P and N:P in secondary forests. The fine root P was positively correlated with soil P in plantations and in coniferous forests, but negatively correlated with soil C:N, C:P and N:P in all forest types. The fine root C in broadleaved and in secondary forests was positively correlated with mean annual precipitation (MAP) and fine root N and N:P in plantations were negatively correlated with MAP. Only the fine root P and C:P in broadleaved forests were correlated with mean annual temperature (MAT). Collectively, forest type, soil C:N:P stoichiometry and climatic factors explained 29, 13 and 12% of the variation in the fine root C, N and P, and their most important explanatory variables were leaf form, soil C:N and soil C:P, respectively. These results advance our knowledge about the regional fine root stoichiometry and its driving factors and provide basic data for improving the key below-ground parameters for biogeochemical models.


Assuntos
Ecossistema , Florestas , Biomassa , Carbono/análise , China , Nitrogênio , Solo
10.
Environ Pollut ; 265(Pt A): 115106, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32806403

RESUMO

The conversion of natural forests to tea plantations largely affects soil nitrous oxide (N2O) emissions and soil microbial communities. However, the impacts of this conversion on the contribution of fungi to N2O emission and on fungal community structure remain unclear. In this study, we determined the soil N2O emission rate, N2O production by fungi, associated fungal community diversity, and related ecological factors in chronological changes of tea crop systems (3, 36 and 105 years old tea orchards named T3, T36 and T105, respectively), and in an adjacent soil from a natural forest. The results indicate that the tea plantations significantly enhanced soil N2O production compared with the forest soil. Tea plantations significantly decreased soil pH and C/N ratio, but increased soil inorganic nitrogen (N). Furthermore, they increased the fungal contribution to the production of soil N2O, but decreased the bacterial counterpart. We also observed that fungal community and functional composition differed distinctly between tea plantations and forest. Additionally, most of the fungal groups in high N2O emission soils (T36 and T105) were identified as the genus Fusarium, which were positively correlated with soil N2O emissions. The variation in N2O emission response could be well explained by NO3--N, soil organic carbon (SOC), C/N, and Fusarium, which contributed to up to 97% of the observed variance. Altogether, these findings provide significant direct evidence that the increase of soil N2O emissions and fungal communities be attributed to the conversion of natural forest to tea plantations.


Assuntos
Micobioma , Carbono/análise , Florestas , Fungos , Solo , Microbiologia do Solo , Chá
11.
Environ Monit Assess ; 192(9): 585, 2020 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-32809133

RESUMO

Wetlands are carbon pools for terrestrial ecosystems and play an important role in the global carbon cycle. The Nanhui tidal flat is located at the Yangtze River estuary and has been disturbed by various human activities. However, the effect of human activities on the carbon accumulation capability and carbon storage of wetlands in the Nanhui tidal flat is poorly understood. In this study, the annual carbon accumulation capability and carbon storage of three types of Spartina alterniflora Loisel. wetlands in the Nanhui tidal flat, which were defined as a natural wetland, silt-promoting wetland, and artificial restored wetland, were evaluated by analyzing the plant carbon fixation capability, soil carbon emissions, and soil organic carbon (SOC) density. The results showed that the three wetlands all had a carbon sink effect and the natural wetland, artificial restored wetland, and silt-promoting wetland annually accumulated 7.94, 7.14, and 6.33 kg m-2 CO2, respectively. The existing SOC density in the subsurface soil (0-40 cm) in the natural wetland, silt-promoting wetland, and artificial restored wetland was 23.26, 17.95, and 12.21 kg m-2 CO2, respectively. The natural wetland, with no human disturbance, had a longer duration of waterlogging and greater tidal nutrition inputs than the other wetlands, resulting in a higher plant biomass and lower soil respiration (SR). It therefore had the strongest carbon accumulation capability and highest SOC storage.


Assuntos
Estuários , Áreas Alagadas , Carbono/análise , China , Ecossistema , Monitoramento Ambiental , Rios , Solo
12.
Environ Sci Pollut Res Int ; 27(30): 38344-38352, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32734542

RESUMO

Some databases report global emissions of certain pollutants. Emissions Database for Global Atmospheric Research (EDGAR) project is one of these, which also records emissions by sources. In this study, the emissions of black and organic carbon and fine particulate matter from the EDGAR database were used as an input to process it in the Sparse Matrix Operator Kernel Emissions (SMOKE) model. We showed the spatial distribution of the fraction of black and organic carbon in particulate matter from each source in the Southern Hemisphere. Also, we extracted these ratios for several cities in the domain of analysis. The results and methodology of this study could improve the emission inventories with bottom-up methodology in areas without information located at Southern Hemisphere. Also, it could be relevant to obtain better performance in air quality modeling at the local level for decision-making on climate change and health effects.


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar/análise , Carbono/análise , Cidades , Mudança Climática , Monitoramento Ambiental , Material Particulado/análise
13.
J Environ Manage ; 273: 111123, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32771850

RESUMO

The Paris Agreement (COP21) further defines the concept of global climate governance as low-carbon green development. Urbanization and carbon emissions are two major characteristics of modern Chinese economic and social development. China's new urbanization requires not only the realization of population, the harmonization of land and economic urbanization also requires the protection of the ecological environment in the process of urbanization to achieve green and low-carbon development. Therefore, it is of great theoretical and practical significance to explore the influencing factors of carbon emissions and compare their differences based on spatial econometric models and from various perspectives of urbanization. Empirical findings of the study are as follows: (1) The Moran's I indexes are all above 0.5, the spatial effects of regional carbon emissions are significant, and it cannot be ignored. Similarly, it shows that the optimal model is a spatial doubly model with dual fixed effects. (2) Direct effects of population, land, and economic urbanization are positive. Whereas, indirect effect about population urbanization is negative, but its total effect is same direction change with carbon emissions. Indirect and total effect of land urbanization are negative, indirect effect of economic urbanization is small and total effect is significantly positive. (3) Per capita GDP, energy intensity, and environmental regulation variables of control variables are all positive; opening to outside be positive but not obvious.


Assuntos
Carbono/análise , Urbanização , Dióxido de Carbono/análise , China , Desenvolvimento Econômico , Paris
14.
J Environ Manage ; 273: 111092, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32805582

RESUMO

Animal excreta are commonly recycled as fertilizers, although attention should be given to environmental impacts. Legislation must also be adapted to new research findings. The framework of this study is an intensive fodder Mediterranean agricultural system affected by EU legislation on the protection of waters against nitrate pollution. This paper studies the effect of two N based dairy cattle slurry (DCS) rates (170 vs. 250 kg N ha-1 yr-1) plus additional mineral N (up to 450 kg N ha-1 divided between two crops), on different soil quality parameters. A control (no N applied) was included. The experiment, which lasted for 8 years, included forage maize followed by ryegrass, grain maize and rapeseed. In the whole period, the organic carbon inputs from the DCS treatments comprised C slurry inputs (14.8 or 21.9 Mg ha-1) plus the C input difference in crop residues (8.3 Mg ha-1) between DCS and the control treatment. In the 0-0.3 m soil depth, slurries significantly increased soil organic carbon (SOC) from by 2.3 or 2.7% yearly (c. 2.8 Mg C with 10 Mg C ha-1 input) mainly in its light fraction. The size of the microbial biomass increased by 5.1% yearly (c. 0.12 Mg C with 10 Mg C ha-1 input). A higher aggregate stability against slaking disruption was observed. Soil pH slightly decreased, P (Olsen) fertility increased (up to 10 mg P kg-1) as did K availability (up to 140 mg K kg-1) and Mn and Ni bioavailability. In rapeseed plants, seed Ca, S, Cu and Mn content increased as did K, S, Fe, Mn and Zn in the rest of the plant biomass. These changes were within acceptable concentration ranges. The higher N rate from DCS has proved useful for the circular nutrient economy, while improving soil physical and chemical quality and the sustainability of the agricultural system as a whole.


Assuntos
Brassica napus , Solo , Agricultura , Animais , Carbono/análise , Bovinos , Fertilizantes/análise , Nitrogênio/análise , Valor Nutritivo
15.
Environ Monit Assess ; 192(8): 555, 2020 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-32740772

RESUMO

This study analyzes the impacts of spatiotemporal changes on C dynamics based on the various C pools and forest structure in western Turkey. The forest C dynamics were projected by forest inventory data between 1972 and 2016, and the spatial distribution of C storage was mapped by GIS. Total C storage increased from 1135.22 Gg in 1972 to 1816.60 Gg in 2016 with a net accumulation of 681.38 Gg. While the largest contribution to C pool was from soil organic carbon with 58.6% and 49.3% of the total C storage in 1972 and 1994, it was from living biomass with 54.0% and 57.7% in 2004 and 2016, respectively. The mean annual C sequestration was 1.57 Mg ha-1 year-1, including 1.49 Mg ha-1 year-1 in biomass and 0.08 Mg ha-1 year-1 in soil over four decades. The mixed cover type was the most significant contributor to biomass, soil, and total C storages. However, the hardwood cover type was the most significant contributor to C densities due to the higher growing stock. The mature development stages (35.6 Gg year-1), the fully covered areas (13.2 Gg year-1), and the older forests have played an essential role in C sequestration. The spatial distribution of C dynamics was heterogenic due to forest cover type, forest structure, and species composition. Monitoring spatiotemporal changes in forest ecosystems in terms of forest cover type, development stage, coverages, and age class distribution can provide opportunities in developing effective forest management policies based on the ecological sustainability of C pools and mitigating climate change effects.


Assuntos
Sequestro de Carbono , Carbono/análise , Biomassa , Ecossistema , Monitoramento Ambiental , Florestas , Solo , Árvores , Turquia
16.
Environ Monit Assess ; 192(9): 604, 2020 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-32857216

RESUMO

Soil quality is the competence of soil to perform necessary functions that are able to maintain animal and plant productivity of the soil. Soil consists of various physical, chemical, and biological parameters, and all these parameters are involved in the critical functioning of soil. There is a need for continuous assessment of soil quality as soil is a complex and dynamic constituent of Earth's biosphere that is continuously changing by natural and anthropogenic disturbances. Any perturbations in the soil cause disturbances in the physical (soil texture, bulk density, etc.), chemical (pH, salinity, organic carbon, etc.), and biological (microbes and enzymes) parameters. These physical, chemical, and biological parameters can serve as indicators for soil quality assessment. However, soil quality assessment cannot be possible by evaluating only one parameter out of physical, chemical, or biological. So, there is an emergent need to establish a minimum dataset (MDS) which shall include physical, chemical, and biological parameters to assess the quality of the given soil. This review attempts to describe various physical, chemical, and biological parameters, combinations of which can be used in the establishment of MDS.


Assuntos
Monitoramento Ambiental , Solo , Animais , Carbono/análise , Plantas , Salinidade
17.
J Environ Sci (China) ; 96: 72-84, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32819701

RESUMO

In this study, the black carbon (BC) measurements in the atmosphere of Nanjing, China were continuously conducted from 2015 to 2018 using a Model AE-33 aethalometer. By combining dataset of PM2.5, PM10, CO, NO2, SO2, O3 and meteorological parameters, the temporal variations and the source apportionment of BC were given in this study. The results showed that the PM2.5 mass concentrations decreased in Nanjing, with an average annual rate of variation of 6.50 µg/(m3⋅year). Differently, the annual average concentrations of BC increased with an average annual variation rate of 214.71 ng/(m3⋅year). The seasonal variations showed the pattern of BC mass concentrations in winter > autumn > spring > summer. The diurnal variations of BC mass concentrations showed a double-peak in all four seasons. The first peak occurred at approximately 7:00 in spring, summer and autumn and around 8:00 in winter. The second peak took place after 18:00. The average AAE (absorption Ångström exponent) was 1.26 with a maximum of 1.35 during wintertime and the lowest (1.12) during summertime. In addition, the AAE was smaller in the daytime than that at night, with a minimum occurring between 13:00 and 14:00. BC and visibility show a good power-function relationship at different humidity levels. The average values of the visibility thresholds of the BC mass concentrations in spring, summer, autumn and winter were 1.326, 5.522, 1.340 and 0.708 µg/m3, respectively. The greater the relative humidity, the smaller the visibility threshold for the BC mass concentrations was.


Assuntos
Poluentes Atmosféricos/análise , Rios , Carbono/análise , China , Monitoramento Ambiental , Material Particulado , Estações do Ano
18.
PLoS One ; 15(8): e0236638, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32764754

RESUMO

Grazing effects on soil properties under different soil and environmental conditions across the globe are often controversial. Therefore, it is essential to evaluate the overall magnitude and direction of the grazing effects on soils. This global meta-analysis was conducted using the mixed model method to address the overall effects of grazing intensities (heavy, moderate, and light) on 15 soil properties based on 287 papers published globally from 2007 to 2019. Our findings showed that heavy grazing significantly increased the soil BD (11.3% relative un-grazing) and PR (52.5%) and reduced SOC (-10.8%), WC (-10.8%), NO3- (-23.5%), and MBC (-27.9%) at 0-10 cm depth, and reduced SOC (-22.5%) and TN (-19.9%) at 10-30 cm depth. Moderate grazing significantly increased the BD (7.5%), PR (46.0%), and P (18.9%) (0-10 cm), and increased pH (4.1%) and decreased SOC (-16.4%), TN (-10.6%), and P (-23.9%) (10-30 cm). Light grazing significantly increased the SOC (10.8%) and NH4+ (28.7%) (0-10 cm). Heavy grazing showed much higher mean probability (0.70) leading to overgrazing than the moderate (0.14) and light (0.10) grazing. These findings indicate that, globally, compared to un-grazing, heavy grazing significantly increased soil compaction and reduced SOC, NO3-, and soil moisture. Moderate grazing significantly increased soil compaction and alkalinity and reduced SOC and TN. Light grazing significantly increased SOC and NH4+. Cattle grazing impacts on soil compaction, SOC, TN, and available K were higher than sheep grazing, but lower for PR. Climate significantly impacted grazing effects on SOM, TN, available P, NH4+, EC, CEC, and PR. Heavy grazing can be more detrimental to soil quality based on BD, SOC, TN, C: N, WC, and K than moderate and light grazing. However, global grazing intensities did not significantly impact most of the 15 soil properties, and the grazing effects on them had insignificant changes over the years.


Assuntos
Carbono/análise , Herbivoria , Gado , Nitrogênio/análise , Solo/química , Animais , Conservação dos Recursos Naturais , Ecossistema
19.
PLoS One ; 15(8): e0230089, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32760138

RESUMO

Ecological stoichiometric should be incorporated into management and nutrient impacted ecosystems dynamic to understand the status of ecosystems and ecological interaction. The present study focused on ecological stoichiometric characteristics of soil, and leaves, stems, and roots of different macrophytes after the banning of seine fishing in Shengjin Lake. For C, N, and P analysis from leaves, stems, roots, and soil to explore their stoichiometric ratio and deriving environmental forces, four dominant plant communities (Vallisneria natans, Zizania latifolia, Trapa natans and Carex schmidtii) were collected. The concentration of C, N, P and C: N: P ratio in leaves, stems, roots, and soil among the plant communities varied significantly. Along the depth gradient high C: N was measured in C.schmidtii soil (7.08±1.504) but not vary significantly (P >0.05). High C: P result was found in T.natans (81.14±43.88) and in V.natans soil (81.40±42.57) respectively with no significant difference (p>0.05). Besides, N: P ratio measured high in V. natans (13.7±4.05) and showed significant variation (P<0.05). High leaf C: N and N: P ratio was measured in C. schmidtii and V. natans respectively. Nevertheless, high leaf C: P ratio was measured in Z. latifolia. From the three studied organs, leaf C: N and N: P ratio showed high values compared to root and stems. The correlation analysis result showed that at 0-10cm depth soil organic carbon (SOC) correlated negatively with stem total phosphorus (STP), and root total nitrogen (RTN) (P<0.05) but positively strongly with leaf total phosphorus (LTP) and leaf total nitrogen (LTN) (P<0.01) respectively. Soil total nitrogen (STN) at 0-10cm strongly positively correlated with leaf total phosphorus (LTP) (P<0.01) and positively with RN: P and leaf total carbon (LTC) (P<0.05). Soil basic properties such as soil moisture content (SMC), bulky density (BD) and pH positively correlated with soil ecological stoichiometric characteristics. Redundancy analysis (RDA) result showed available nitrogen (AN), soil total nitrogen (STN), and available phosphorus (AP) were the potential determinants variables on plants stoichiometric characteristics.


Assuntos
Plantas/química , Solo/química , Carbono/análise , Carex (Planta) , China , Ecossistema , Eleocharis , Hydrocharitaceae , Lagos , Nitrogênio/análise , Fósforo/análise , Folhas de Planta/química , Raízes de Plantas/química , Caules de Planta/química , Poaceae , Áreas Alagadas
20.
J Environ Manage ; 274: 110953, 2020 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-32795813

RESUMO

The continuously increasing carbon emissions have become a significant hurdle for global sustainable development. Technological progress is considered essential for controlling carbon emissions. However, previous literature has analyzed technological progress as a whole, largely ignoring its spatial spillovers. Therefore, our understanding of how technological progress influences carbon emissions is still limited. To fill this gap, we conduct an in-depth analysis of the effect of technological progress regarding carbon emissions by introducing a new framework that combines the slacks-based measure of the Malmquist-Luenberger index and the spatial dynamic model. Employing a Chinese provincial panel dataset for 2000-2016 as a case study, the conventional analysis indicates that both technological progress and its components have not played a significant role in decreasing carbon emissions. A further analysis using the spatial dynamic model suggests that the technological progress of neighbouring regions plays a significant role in reducing carbon emissions. Moreover, the effect of efficiency change is stronger than that of technical change, which provides new evidence on how technological progress influences carbon emissions.


Assuntos
Carbono/análise , Tecnologia , Dióxido de Carbono/análise , China , Eficiência
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