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1.
J Environ Manage ; 289: 112486, 2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-33831757

RESUMO

Climate change is a global issue threatening agricultural production and human survival. However, agriculture sector is a major source of global greenhouse gases (GHGs), especially CH4 and N2O. Crop residue returning (RR) is an efficient practice to sequestrate soil carbon and increase crop yields. However, the efficiency of RR to mitigate climate change and maintain food security will be affected by the response of GHG emissions at both per area-scale and per yield-scale. Therefore, a national meta-analysis was conducted using 309 comparisons from 44 publications to assess the responses of GHG emissions to RR in China's croplands. The results indicated that little response of GWP to RR was observed with conditions under lower nitrogen fertilizer input rates (0-120 kg ha-1), mulch retention, returning one time in double cropping systems, returning with half residue, weakly acidic soil (pH 5.5-6.5), initial SOC contents >20 g kg-1, or mean annual precipitation <1000 mm. In order to mitigate climate change and sustain food security, RR combined with paddy-upland rotation, nitrogen fertilizer input rates of 240-360 kg ha-1, and neutral soil (pH 6.5-7.5) could decrease GWP at per unit of crop yield, which ultimately leads to a lower effect on GHGI and a higher crop production efficiency. In-depth studies should be conducted in the future to explore the interactions between various factors influencing GHG emissions under RR conditions. Overall, optimizing the interactions with management and site-specific conditions, potential for regulating GHGs emissions of RR can be enhanced.


Assuntos
Gases de Efeito Estufa , Oryza , Agricultura , China , Produtos Agrícolas , Aquecimento Global , Efeito Estufa , Gases de Efeito Estufa/análise , Humanos , Metano/análise , Óxido Nitroso/análise , Solo
2.
J Environ Manage ; 289: 112526, 2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-33848879

RESUMO

Methane (CH4) is a prominent Greenhouse Gas (GHG) and its global atmospheric concentration has increased significantly since the year 2007. Anthropogenic CH4 emissions are projected to be 9390 million metric tonnes by 2020. Here, we present the long-term changes in atmospheric methane over India and suggest possible alternatives to reduce soil emissions from paddy fields. The increase in atmospheric CH4 concentrations from 2009 to 2020 in India is significant, about 0.0765 ppm/decade. The Indo-Gangetic Plains, Peninsular India and Central India show about 0.075, 0.076 and 0.074 ppm/decade, respectively, in 2009-2020. Seasonal variations in CH4 emissions depend mostly on agricultural activities and meteorology, and contribution during the agricultural intensive period of Kharif-Rabi (i.e., June-December) is substantial in this regard. The primary reason for agricultural soil emissions is the application of chemical fertilizers to improve crop yield. However, for rice farming, soil amendments involving stable forms of carbon can reduce GHG emissions and improve soil carbon status. High crop production in pot culture experiment resulted in lower potential yield-scaled GHG emissions in rice with biochar supplement. The human impact of global warming induced by agricultural activities could be reduced by using biochar as a natural solution.


Assuntos
Gases de Efeito Estufa , Oryza , Agricultura , Fertilizantes/análise , Aquecimento Global , Gases de Efeito Estufa/análise , Humanos , Índia , Metano/análise , Óxido Nitroso/análise , Solo
3.
Environ Sci Technol ; 55(8): 4440-4451, 2021 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-33793238

RESUMO

Pig production contributes considerably to land use and greenhouse gas (GHG) and reactive nitrogen (Nr) emissions. Land use strategies were widely proposed, but the spillover effects on biological flow are rarely explored. Here, we simultaneously assessed the carbon (C), nitrogen (N), and cropland footprints of China's pig production at the provincial scale in 2017. The environmental impacts of land use strategies were further evaluated. Results show that one kg live-weight pig production generated an average of 1.9 kg CO2-equiv and 59 g Nr emissions, occupying 3.5 m2 cropland, with large regional variations. A large reduction in GHG (58-64%) and Nr (12-14%) losses and occupied cropland (10-11%) could be achieved simultaneously if combined strategies of intensive crop production, improved feed-protein utilization efficiency, and feeding co-products were implemented. However, adopting a single strategy may have environmental side-effects. Reallocating cropland that pigs used for feed to plant food alternatives would enhance human-edible energy (3-20 times) and protein delivery (1-5 times) and reduce C and N footprints, except for rice and vegetables. Reallocating cropland to beef and milk production would decrease energy and protein supply. Therefore, a proper combination of land use strategies is essential to alleviate land use changes and nutrient emissions without sacrificing food supply.


Assuntos
Efeito Estufa , Gases de Efeito Estufa , Animais , Pegada de Carbono , Bovinos , China , Gases de Efeito Estufa/análise , Nitrogênio/análise , Suínos
4.
Artigo em Inglês | MEDLINE | ID: mdl-33809113

RESUMO

Decreased greenhouse gas emissions (GHG) are urgently needed in view of global health threat represented by climate change. The goal of this paper is to test the validity of the Environmental Kuznets Curve (EKC) hypothesis, considering less common measures of environmental burden. For that, four different estimations are done, one considering total GHG emissions, and three more taking into account, individually, the three main GHG gases-carbon dioxide (CO2), nitrous oxide (N2O), and methane gas (CH4)-considering the oldest and most recent economies adhering to the EU27 (the EU 15 (Old Europe) and the EU 12 (New Europe)) separately. Using panel dynamic fixed effects (DFE), dynamic ordinary least squares (DOLS), and fully modified ordinary least squares (FMOLS) techniques, we validate the existence of a U-shaped relationship for all emission proxies considered, and groups of countries in the short-run. Some evidence of this effect also exists in the long-run. However, we were only able to validate the EKC hypothesis for the short-run in EU 12 under DOLS and the short and long-run using FMOLS. Confirmed is the fact that results are sensitive to models and measures adopted. Externalization of problems globally takes a longer period for national policies to correct, turning global measures harder and local environmental proxies more suitable to deeply explore the EKC hypothesis.


Assuntos
Gases de Efeito Estufa , Dióxido de Carbono/análise , Desenvolvimento Econômico , Europa (Continente) , Efeito Estufa , Gases de Efeito Estufa/análise , Metanol , Óxido Nitroso/análise
5.
J Environ Manage ; 287: 112334, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33735676

RESUMO

Livestock production is the major livelihood for a growing local population on the Tibetan plateau. However, government policy is to reduce the number of livestock due to the large quantities of greenhouse gasses (GHG), in particular methane, produced by ruminants and the degradation of the grasslands. For this policy to be effective, with little effect on livelihoods, there should be a decoupling of GHG emissions from economic growth of livestock products. This study examined the synergetic effects of policies, extreme climate events and GHG emissions from livestock at the headwater region of the Yellow River since 1980. Optimization models of GHG emissions efficiency and drivers were developed and parameterized. Trade-offs between GHG emissions from livestock and economic growth from livestock, determined by the decoupling model, showed that from 1980 to 2015: 1) the GHG emissions decreased by 39%; (2) CH4 emissions from livestock decreased by 33%, and yaks emitted the most (accounted for 99.6%) among livestock; (3) N2O emissions decreased by 34%; (4) trade-offs between livestock GHG emissions and grassland uptake indicated that the grazing livestock system functioned as a net carbon sink; (5) the efficiency factor, especially technical efficiency, was the main driver of GHG emissions; and (6) GHG emissions from livestock were in a decoupling state from economic growth from livestock. However, decoupling has not been stable as inter-annual fluctuations have been large mainly due to extreme climatic events, such as snowstorm disasters, which indicates that the grazing system was still relatively fragile. The GHG emissions can be reduced further by mitigating CH4 emissions, and enhancing CO2 sequestration on grazed pastureland. The ongoing transformation of livestock industry development on the Tibetan plateau is associated with uncertainty under the background of global GHG mitigation.


Assuntos
Gases de Efeito Estufa , Animais , Desenvolvimento Econômico , Efeito Estufa , Gases de Efeito Estufa/análise , Gado , Metano/análise , Óxido Nitroso/análise , Tibet
6.
Water Res ; 196: 117056, 2021 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-33774352

RESUMO

The impact of cultural eutrophication on carbon cycling in subtropical reservoirs was assessed using high-resolution measurements of dissolved gas concentration, atmospheric exchange, and uptake/production rates of methane, carbon dioxide, and oxygen. Seasonal measurements were performed in two reservoirs that pertain to the same hydrological basin but are drastically different in terms of allochthonous carbon input. These results were used to feed a mass balance model, from which a large number of overall parameters were determined to explicitly describe the dynamics and spatial attributes of the carbon cycle in the reservoirs. A single graphical representation of each reservoir was created to facilitate an overall appraisal of the carbon cycle. The impact of cultural eutrophication was profound and resulted in a complete redistribution of how the various bioprocesses participated in the methane, carbon dioxide, and oxygen cycles. Among several identified impacts of eutrophication, it was observed that while eutrophication triggered increased methane production, this effect was followed by a similar increase in methane emissions and methanotrophic rates, while gross primary production was depleted.


Assuntos
Gases de Efeito Estufa , Dióxido de Carbono/análise , Monitoramento Ambiental , Eutrofização , Gases de Efeito Estufa/análise , Metano/análise , Oxigênio
7.
Sci Total Environ ; 768: 144582, 2021 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-33736331

RESUMO

Greenhouse gases (GHGs) have long received public attention because they affect the Earth's climate by producing the greenhouse effect. Freshwaters are an important source of GHGs, and the enhancement in their eutrophic status affects GHG emissions. Along with the increasing eutrophication of water bodies, the relevant quantitative and qualitative studies of the effects of freshwater eutrophication on GHG emissions have made substantial progress, particularly in the past 5 years. However, to our knowledge, this is the first critical review to focus on the role of freshwater eutrophication in GHG emissions. In this review, the emissions of common GHGs from freshwater are quantitatively described. Importantly, direct (i.e., dissolved oxygen, organic carbon, and nutrients) and indirect factors (i.e., dominant primary producer and algal blooms) affecting GHG emissions from eutrophic freshwater are systematically analyzed. In particular, the existence and significance of feedback loops between freshwater eutrophication and GHG emissions are emphasized considering the difficulties managing freshwater ecosystems and the Earth's climate. Finally, several future research directions as well as mitigation measures are described to provide useful insight into the dynamics and control of GHG emissions.


Assuntos
Gases de Efeito Estufa , Ecossistema , Eutrofização , Água Doce , Efeito Estufa , Gases de Efeito Estufa/análise
8.
Ying Yong Sheng Tai Xue Bao ; 32(3): 942-950, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33754560

RESUMO

The strategy of few or no-phosphorus fertilization in rice season but more in wheat season can effectively increase phosphorus use efficiency and reduce phosphorus loss through runoff and leaching. It remains unknown whether the lack of phosphorus will affect greenhouse gas emission in the rice season. We monitored the CH4 and N2O emission fluxes during the growth period of rice treated with normal phosphorus application (NPK) and no-phosphorus application (NK) in two long-term experimental fields in Suzhou and Yixing. The results showed that long-term no-phosphorus application promoted CH4 and N2O emission in both fields. Compared with the NPK treatment, CH4 and N2O emissions from the NK treatment significantly increased by 57% and 25% in Suzhou experi-mental field, respectively, while those in Yixing experimental field were also significantly increased by 221% and 70%, respectively. The contents of organic acid, dissolved organic carbon and available phosphorus in soil were reduced under long-term NK treatment, and they were closely related to CH4 emission. Soil available phosphorus content was significantly negatively correlated with CH4 emission (r=-0.987). The global warming potential (GWP) was greater in NK treatment than NPK treatment in both fields. Therefore, long-term no-phosphorus application could decrease the contents of organic acid, soluble organic carbon, and available phosphorus in soils, resulting in more CH4 and N2O emission in rice field.


Assuntos
Gases de Efeito Estufa , Oryza , Agricultura , China , Fertilização , Fertilizantes , Gases de Efeito Estufa/análise , Metano/análise , Óxido Nitroso/análise , Fósforo , Solo
9.
Sci Total Environ ; 775: 145861, 2021 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-33621871

RESUMO

Plant invasions represent a major global change in land/vegetation cover with the potential to significantly modify greenhouse gas (GHG) emissions. To get a better understanding of the impacts of terrestrial invasive plants on soil GHG emissions we report, firstly, on experiments conducted on invasive populations of the N-fixing herbaceous species Gunnera tinctoria in Ireland, and secondly, compare our results with published information based on a systematic review of the literature. For G. tinctoria populations, there was a >50% reduction in soil CO2 emissions, mainly due to a reduction in autotrophic respiration, but with little impact on annual N2O or CH4 budgets. One year after the removal of G. tinctoria, soil GHG emissions returned to values comparable to uninvaded areas and this was associated with the reestablishment of the vegetation and an increased root biomass per unit area. If G. tinctoria covered 10% of abandoned agricultural land in Ireland, this could be associated with a reduction of approximately 8% (or 4.988 Mt CO2eq y-1) of the country's national CO2 emissions. Comparisons of these results with literature values were difficult because of the often low and limited sampling effort of previous investigations, a failure to assess all three major GHGs and because of marked seasonal variations. We found 46 studies that documented results for 16 species. From the studies that measured soil respiration, it was enhanced in only 45% of cases, questioning the assumption that invasive plants always increase soil CO2 emissions. In 25 cases that analysed methane, CH4 emissions increased in 76% of them, but all of these were conducted in wetlands. In only two cases were N-fixing species associated with enhanced N2O emissions. Our results argue for more detailed and comprehensive assessments of the effect of plant invasions on GHG emissions and their global impact.


Assuntos
Gases de Efeito Estufa , Dióxido de Carbono/análise , Monitoramento Ambiental , Efeito Estufa , Gases de Efeito Estufa/análise , Espécies Introduzidas , Irlanda , Metano/análise , Óxido Nitroso/análise , Plantas , Solo
10.
Water Res ; 193: 116858, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33540345

RESUMO

Due to regular influx of organic matter and nutrients, waste stabilization ponds (WSPs) can release considerable quantities of greenhouse gases (GHGs). To investigate the spatiotemporal variations of GHG emissions from WSPs with a focus on the effects of sludge accumulation and distribution, we conducted a bathymetry survey and two sampling campaigns in Ucubamba WSP (Cuenca, Ecuador). The results indicated that spatial variation of GHG emissions was strongly dependent on sludge distribution. Thick sludge layers in aerated ponds and facultative ponds caused substantial CO2 and CH4 emissions which accounted for 21.3% and 78.7% of the total emissions from the plant. Conversely, the prevalence of anoxic conditions stimulated the N2O consumption via complete denitrification leading to a net uptake from the atmosphere, i.e. up to 1.4±0.2 mg-N m-2 d-1. Double emission rates of CO2 were found in the facultative and maturation ponds during the day compared to night-time emissions, indicating the important role of algal respiration, while no diel variation of the CH4 and N2O emissions was found. Despite the uptake of N2O, the total GHG emissions of the WSP was higher than constructed wetlands and conventional centralized wastewater treatment facilities. Hence, it is recommended that sludge management with proper desludging regulation should be included as an important mitigation measure to reduce the carbon footprint of pond treatment facilities.


Assuntos
Gases de Efeito Estufa , Dióxido de Carbono/análise , Equador , Monitoramento Ambiental , Efeito Estufa , Gases de Efeito Estufa/análise , Metano/análise , Óxido Nitroso/análise , Tanques , Esgotos
11.
Water Res ; 193: 116875, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33550166

RESUMO

Wetlands are among the earth's most efficient ecosystems for carbon sequestration, but can also emit potent greenhouse gases (GHGs) depending on how they are managed. Global management strategies have sought to maximize carbon drawdown by wetlands by manipulating wetland hydrology to inhibit bacterially-mediated emissions. However, it has recently been hypothesized within wetlands that viruses have the potential to dictate the magnitude and direction of GHG emissions by attacking prokaryotes involved in the carbon cycle. Here we tested this hypothesis in a whole-ecosystem manipulation by hydrologically-restoring a degraded wetland ('rewetting') and investigated the changes in GHG emissions, prokaryotes, viruses, and virus-host interactions. We found that hydrological restoration significantly increased prokaryotic diversity, methanogenic Methanomicrobia, as well as putative iron/sulfate-cyclers (Geobacteraceae), nitrogen-cyclers (Nitrosomonadaceae), and fermentative bacteria (Koribacteraceae). These results provide insights into successional microbial community shifts during rehabilitation. Additionally, in response to watering, viral-induced prokaryotic mortality declined by 77%, resulting in limited carbon released by viral shunt that was significantly correlated with the 2.8-fold reduction in wetland carbon emissions. Our findings highlight, for the first time, the potential implications of viral infections in soil prokaryotes on wetland greenhouse gas dynamics and confirm the importance of wetland rehabilitation as a tool to offset carbon emissions.


Assuntos
Gases de Efeito Estufa , Vírus , Dióxido de Carbono/análise , Ecossistema , Gases de Efeito Estufa/análise , Metano/análise , Óxido Nitroso/análise , Solo , Áreas Alagadas
12.
Sci Total Environ ; 767: 145021, 2021 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-33636794

RESUMO

Biochar management has been proposed as a promising strategy to mitigate climate change. However, the long-term effects of biochar amendment on soil greenhouse gas (GHG) production and microbial community in forest ecosystems under projected warming remain highly uncertain. In this study, we conducted a 49-day incubation experiment to investigate the impact of biochar application on soil physico-chemical properties, GHG production rates, and microbial community at three temperature levels using a temperate forest soil amended with spruce biochar four years ago. Our results showed that temperature exerted a positive effect on soil CO2, CH4 and N2O production, leading to an increase in total global warming potential by 169% and 87% as temperature rose from 5 to 15 °C and from 15 to 25 °C, respectively, and thus a positive feedback to warming. Moreover, warming was found to reduce soil microbial biomass significantly, but at the same time promote the selection of an activated microbial community towards some phyla, e.g. Acidobacteria and Actinobacteria. We observed that biochar amendment reduced soil CH4 consumption and N2O production in the absence of litter by 106% and 94%, respectively, but did not affect soil CO2 production. While biochar had no significant influence of total global warming potential of forest soil, it could promote climate change mitigation by increasing the total soil carbon content by 26% in the presence of litter. In addition, biochar application was shown to enhance soil available phosphorus and dissolved organic carbon concentrations, as well as soil microbial biomass under a warmer environment. Our findings highlighted the potential of spruce biochar as a soil amendment in improving soil fertility and carbon sequestration in temperate forest over the long term, without creating any adverse climatic impacts associated with soil GHG production.


Assuntos
Gases de Efeito Estufa , Microbiota , Agricultura , Dióxido de Carbono/análise , Carvão Vegetal , Florestas , Gases de Efeito Estufa/análise , Óxido Nitroso/análise , Solo , Temperatura
13.
Chemosphere ; 273: 129694, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33524744

RESUMO

Greenhouse gases (GHGs; particularly, CO2, CH4, and N2O) emission from wastewater treatment systems (WWTS) is one of the inevitable concerns for sustainable development. This indicator is directly linked with the carbon footprint and potential impacts of WWTS on climate change. In this view, various modeling, design, and operational tools have been introduced to mitigate the WWTS associated GHGs, at regional and global scales. In this study, authors have critically reviewed the selected potential operational control strategies for GHGs emission, particularly emitted from the operational stages of biological WWTS. The investigated operational control strategies and/or treatment configurations included intermittent aeration, varying dissolved oxygen, enhanced sludge retention time, coupled aerobic-anoxic nitrous decomposition operation, and microalgae integrated treatment process. Based on this analysis and considering the trade-off between treatment performance of WWTS and GHGs control, an integrated framework is also proposed for existing and upcoming WWTS. The findings of this study and proposed framework will play an instrumental role in mitigating the GHGs at various operational stages of WWTS. Future research works in this direction can lead to a better understanding of investigated operational GHGs emission control strategies in WWTS.


Assuntos
Gases de Efeito Estufa , Purificação da Água , Dióxido de Carbono/análise , Efeito Estufa , Gases de Efeito Estufa/análise , Metano/análise , Óxido Nitroso/análise
14.
Animal ; 15(1): 100023, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33515989

RESUMO

Improved animal health can reduce greenhouse gas (GHG) emissions intensity in livestock systems while increasing productivity. Integrated modelling of disease impacts on farm-scale emissions is important in identifying effective health strategies to reduce emissions. However, it requires that modellers understand the pathways linking animal health to emissions and how these might be incorporated into models. A key barrier to meeting this need has been the lack of a framework to facilitate effective exchange of knowledge and data between animal health experts and emissions modellers. Here, these two communities engaged in workshops, online exchanges and a survey to i) identify a comprehensive list of disease-related model parameters and ii) test its application to evaluating models. Fifty-six parameters were identified and proved effective in assessing the potential of farm-scale models to characterise livestock disease impacts on GHG emissions. Easy wins for the emissions models surveyed include characterising disease impacts related to feeding.


Assuntos
Gases de Efeito Estufa , Animais , Fazendas , Efeito Estufa , Gases de Efeito Estufa/análise , Gado
15.
Sci Total Environ ; 770: 144557, 2021 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-33508664

RESUMO

Soils can influence climate by sequestering or emitting greenhouse gases (GHG) such as carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). We are far from understanding the direct influence of cryptogamic covers on soil GHG fluxes, particularly in areas free of potential anthropogenic confounding factors. We assessed the role of well-developed cryptogamic covers in soil attributes, as well as in the in-situ exchange of GHG between Antarctic soils and the atmosphere during the austral summer. We found lower values of soil organic matter, total organic carbon, and total nitrogen in bare areas than in soils covered by mosses and, particularly, lichens. These differences, together with concomitant decreases and increases in soil temperature and moisture, respectively, resulted in increases in in-situ CO2 emission (i.e. ecosystem respiration) and decreases in CH4 uptake but no significant changes in N2O fluxes. We found consistent linear positive and negative relationships between soil attributes (i.e. soil organic matter, total organic carbon and total nitrogen) and CO2 emissions and CH4 uptake, respectively, and polynomial relationships between these soil attributes and net N2O fluxes. Our results indicate that any increase in the area occupied by cryptogams in terrestrial Antarctic ecosystems (due to increased growing season and increasingly warming conditions) will likely result in parallel increases in soil fertility as well as in an enhanced capacity to emit CO2 and a decreased capacity to uptake CH4. Such changes, unless offset by parallel C uptake processes, would represent a paradigmatic example of a positive climate change feedback. Further, we show that the fate of these terrestrial ecosystems under future climate scenarios, as well as their capacity to exchange GHG with the atmosphere might depend on the relative ability of different aboveground cryptogams to thrive under the new conditions.


Assuntos
Gases de Efeito Estufa , Regiões Antárticas , Dióxido de Carbono/análise , Ecossistema , Gases de Efeito Estufa/análise , Metano/análise , Óxido Nitroso/análise , Solo
16.
Sci Total Environ ; 768: 144370, 2021 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-33454466

RESUMO

The landscapes of high-altitude wetland ecosystems are characterized by different kinds of aquatic sites, including ponds holding conspicuous microbial life. Here, we examined a representative pond of the wetland landscape for dynamics of greenhouse gases, and their association with other relevant biogeochemical conditions including diel shifts of microbial communities' structure and activity over two consecutive days. Satellite image analysis indicates that the area of ponds cover 238 of 381.3 Ha (i.e., 62.4%), representing a significant landscape in this wetland. Solar radiation, wind velocity and temperature varied daily and between the days sampled, influencing the biogeochemical dynamics in the pond, shifting the pond reservoir of inorganic versus dissolved organic nitrogen/phosphorus bioavailability, between day 1 and day 2. Day 2 was characterized by high dissolved organic nitrogen/phosphorus and N2O accumulation. CH4 presented a positive excess showing maxima at hours of high radiation during both days. The microbial community in the sediment was diverse and enriched in keystone active groups potentially related with GHG recycling including bacteria and archaea, such as Cyanobacteria, Verrucomicrobia, Rhodobacterales and Nanoarchaeaota (Woesearchaeia). Archaea account for the microbial community composition changes between both days and for the secondary productivity in the water measured during day 2. The results indicate that an intense recycling of organic matter occurs in the pond systems and that the activity of the microbial community is correlated with the availability of nutrients. Together, the above results indicate a net sink of CO2 and N2O, which has also been reported for other natural and artificial ponds. Overall, our two-day fluctuation study in a representative pond of a high-altitude wetland aquatic landscape indicates the need to explore in more detail the short-term besides the long-term biogeochemical variability in arid ecosystems of the Andes plateau, where wetlands are hotspots of life currently under high anthropogenic pressure.


Assuntos
Gases de Efeito Estufa , Altitude , Archaea , Bactérias , Gases de Efeito Estufa/análise , Metano/análise , Áreas Alagadas
17.
Environ Sci Pollut Res Int ; 28(16): 20451-20475, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33410023

RESUMO

Cement is a basic requirement of today's society and is the only thing that humans consume more volume than water, but cement manufacturing is the most energy- and emission-intensive process. Hence, the cement industry is currently under pressure to reduce greenhouse gases (GHGs) emissions. Climate change mitigation strategies implemented in the industry leads to GHGs reduction, climate risks, pollutants, and another adverse impact on the environment. In order to implement climate change mitigation strategies in the cement industry, a careful analysis of barriers that hinder the emission reduction must be taken. However, most existing research on the barriers to mitigation measures is focused on developed countries. Among the most important emerging economies, India, the second-largest producer and consumer of cement, faces challenges to implement emission reduction measures. To bridge this gap, this paper identifies and evaluates the barriers and solutions to overcome these barriers in the context of India. This study employs a three-phase methodology based on fuzzy analytical hierarchy process (AHP) and fuzzy technique for order performance by similarity to ideal solution (TOPSIS) to identify barriers and solutions to overcome these barriers to climate change mitigation strategies adoption in Indian cement industry. Fuzzy AHP is employed to prioritize these barriers, and to rank solutions of these barriers, Fuzzy TOPSIS is employed. Ten Indian cement manufacturing industry is taken to illustrate the proposed three-phase methodology. Finally, the result of the analysis offers an effective decision support tool to the Indian cement industry to eliminate and overcome barriers to mitigation strategies adoption and build their green image in the market.


Assuntos
Mudança Climática , Gases de Efeito Estufa , Materiais de Construção , Gases de Efeito Estufa/análise , Humanos , Índia , Indústrias
18.
Environ Sci Pollut Res Int ; 28(15): 19412-19423, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33394443

RESUMO

The acceptance of combined pre-composting and vermicomposting systems is increasing because of the advantage in rapidly stabilizing organic wastes and reducing emission of greenhouse gasses (GHG). However, GHG emission during the pre-composting phase is often neglected when evaluating the system. This study aimed to quantify GHG emission from a combined pre-composting and vermicomposting system and to investigate the effects of earthworms on GHG emission. A combined system using Eisenia fetida was employed to stabilize maize stover and cow dung (mixing ratio 60:40). The inoculating densities were 60 (T1), 120 (T2), and 180 (T3) earthworms per kilogram of substrate. A traditional composting system without earthworms was set as a control (T0). The results indicated that earthworms increased CO2 while decreased CH4 and N2O emissions compared to the control. Higher emission of CO2 suggested that the earthworms promoted the degradation of the substrates. Lower emission of CH4 and N2O showed the advantage of the combined system because CH4 and N2O possess extremely higher global warming potential than that of CO2. T2 is recommended for stabilizing maize stover and cow dung when making a tradeoff between stabilization rate and reduction of GHG. The percentages of GHG emission during pre-composting relative to total GHG emission in T1, T2, and T3 were 34%, 35%, and 30%, respectively. GHG emission is non-negligible when using a combined system, especially the emission of GHG during the pre-composting phase cannot be ignored.


Assuntos
Compostagem , Gases de Efeito Estufa , Animais , Bovinos , Feminino , Gases de Efeito Estufa/análise , Metano/análise , Nitrogênio/análise , Solo , Zea mays
19.
Environ Pollut ; 274: 116483, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33508717

RESUMO

The effect of modified biochar on the greenhouse gas emission in soil is not clear until now. In this study, biochar (BC) was modified by phosphoric acid (P) and further combined with nano-zero-valent iron (nZVI) to form nZVI-P-BC composite. The P modified biochar could significantly increase the available phosphorus in soil. The release of CO2 and N2O in soil was inhibited during the initial stage of the experiment, with inhibition becoming more obvious over time. On the contrary, CH4 and N2O emission in soil was enhanced by nZVI-P-BC composite. The proportion of Sphingomonas and Gemmatimonas were the most abundant bacterial species, which were related to the metabolism and transformation of nitrogen. The community structure of the fungus was also affected by nZVI-P-BC composite with Fusarium as the main species. PCoA analysis result suggested that bacterial community was more affected by the incubation time while fungal community was more related to the addition of different biochar and modified biochars.


Assuntos
Gases de Efeito Estufa , Microbiota , Carvão Vegetal , Gases de Efeito Estufa/análise , Ferro , Fósforo , Solo
20.
Glob Chang Biol ; 27(8): 1645-1661, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33421219

RESUMO

Many studies have assessed the potential of agricultural practices to sequester carbon (C). A comprehensive evaluation of impacts of agricultural practices requires not only considering C storage but also direct and indirect emissions of greenhouse gases (GHG) and their side effects (e.g., on the water cycle or agricultural production). We used a high-resolution modeling approach with the Simulateur mulTIdisciplinaire pour les Cultures Standard soil-crop model to quantify soil organic C (SOC) storage potential, GHG balance, biomass production and nitrogen- and water-related impacts for all arable land in France for current cropping systems (baseline scenario) and three mitigation scenarios: (i) spatial and temporal expansion of cover crops, (ii) spatial insertion and temporal extension of temporary grasslands (two sub-scenarios) and (iii) improved recycling of organic resources as fertilizer. In the baseline scenario, SOC decreased slightly over 30 years in crop-only rotations but increased significantly in crop/temporary grassland rotations. Results highlighted a strong trade-off between the storage rate per unit area (kg C ha-1  year-1 ) of mitigation scenarios and the areas to which they could be applied. As a result, while the most promising scenario at the field scale was the insertion of temporary grassland (+466 kg C ha-1  year-1 stored to a depth of 0.3 m compared to the baseline, on 0.68 Mha), at the national scale, it was by far the expansion of cover crops (+131 kg C ha-1  year-1 , on 17.62 Mha). Side effects on crop production, water irrigation and nitrogen emissions varied greatly depending on the scenario and production situation. At the national scale, combining the three mitigation scenarios could mitigate GHG emissions of current cropping systems by 54% (-11.2 from the current 20.5 Mt CO2 e year-1 ), but the remaining emissions would still lie far from the objective of C-neutral agriculture.


Assuntos
Gases de Efeito Estufa , Agricultura , Carbono , Produtos Agrícolas , França , Efeito Estufa , Gases de Efeito Estufa/análise , Solo
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