Carbon Dioxide Emission Rates Research Articles

Post-fire soil carbon emission rates along boreal forest fire chronosequences in northwest Canada show significantly higher emission potentials from permafrost soils compared to non-permafrost soils

Boreal forests are one of the most important biomes storing carbon (C). Wildfires burn yearly on average more than 1% of the boreal forest, and it is expected that the fire return intervals will shorten due to climate change. Fire is one of the most influential factors affecting soil organic matter quantity and quality, soil C pools, and presumably also the time C resides in the soil (soil C turnover time in years). We compared the potential effects of forest fire through post-fire succession on soil carbon dioxide (CO2) emission rates and soil C turnover time in two fire chronosequences, one with underlying permafrost soil and the other without permafrost. We found that fire had a significant effect on potential soil C turnover times, but surprisingly there was no significant difference in soil C turnover times between the permafrost and non-permafrost areas, although the soil CO2 emissions rates in permafrost areas are approximately three times higher compared to non-permafrost areas. In recently burned areas the potential soil C turnover times were two times longer compared to control areas located in forests burned more than 100 years ago. The longest potential soil C turnover times were recorded in mineral soil layers (30 cm) of permafrost soils, and the shortest potential soil C turnover times were recorded in humus layers of non-permafrost areas.

Modeling Mushrooms’ Carbon Dioxide Emission and Heat Exchange Rates for Synergistic Cultivation with Leafy Greens

The cultivation of mushrooms in controlled environments generates a significant amount of CO2 as a by-product. This presents opportunities for carbon dioxide (CO2) enrichment in leafy green production. This study aimed to develop a model for CO2 emission and heat exchange rates that can be used to support the synergistic cultivation of mushrooms and leafy greens. This was achieved by aggregating data from literature with experimental data gathered in two different testing spaces. The average CO2 emission and heat exchange rates for shiitake incubated at 21 °C were determined and a CO2 emission rate model for mixed substrate in incubation was developed based on indoor temperature variations. The results indicated that oyster mushrooms have a notable CO2 enrichment potential, twice that of shiitake in the incubation stage and five times more in fructification. Additionally, oyster mushrooms released a significant amount of heat during incubation. In contrast, shiitake mushrooms with their minimal heat exchange rate during incubation could offer an energy-efficient option for synergistic cultivation with leafy greens in environments where cooling is required year-round. Moreover, it was observed that the CO2 emission rate of a full-scale incubation chamber is strongly correlated with indoor temperature. These findings offer valuable information for modeling the CO2 emission and heat exchange rates of mushroom and leafy green farms.

Quantitative analysis of diurnal CO2 flux variations above an alkaline playa

AbstractThe alkaline playas at Atlin, BC, provide a unique opportunity for studying the carbonate–bicarbonate system and carbonate mineral stability at the Earth's surface. In this study, dynamic closed chambers (DCCs) and pore‐gas sampling were used to directly quantify carbon dioxide (CO2) emission rates and characterize processes governing the CO2 exchange across the playa‐atmosphere interface. Data were collected at the Atlin site continuously over 27 days in 2020 and 14 days in 2021. Results indicate minimal net exchange of CO2 across the playa‐atmosphere interface during the monitoring periods, with average fluxes over the two periods of −0.03 and 0.09 µmol m−2 s−1 in 2020 and 2021, respectively. However, distinct diurnal oscillations of CO2 fluxes were measured with average daytime fluxes of 0.15 ± 0.34 µmol m−2 s−1 (2020) and 0.15 ± 0.19 µmol m−2 s−1 (2021) and nighttime fluxes of −0.24 ± 0.31 µmol m−2 s−1 (2020) and 0.04 ± 0.18 µmol m−2 s−1 (2021). These observations, supported by reactive transport modeling, indicate that CO2 exchange is predominantly governed by changes in CO2 solubility in alkaline porewater related to diurnal temperature fluctuations and variations in CO2 concentrations in ambient air above the ground surface. Even though CO2 concentrations exceed 8000 ppmv at 1‐m depth, CO2 emissions to the atmosphere were found to be minimal, likely due to high moisture contents, low connectivity, and tortuosity, limiting upward CO2 migration. These findings provide insights into CO2 flux dynamics in alkaline arid regions and show promise for the application of the DCC method for monitoring ex situ carbon mineralization at sites with enhanced mineral weathering.

Экологическая оценка скорости эмиссии диоксида углерода с поверхности субстрата ксилотрофных грибов

The article presents data on the ecological assessment of the rate of emission flows from the surface of blocks of xylotrophic fungi. Data on the rate of carbon dioxide emission and the intensity of respiration of the mushroom block are presented. Keywords: CARBON DIOXIDE EMISSION, XYLOTROPHIC FUNGI, CARBON DIOXIDE, RESPIRATION RATE

Wind Turbine-Fuel Cell Power System for Supplying Isolated Sites

The present work aims to develop a dynamic Wind Turbine-Fuel Cell (WT-FC) hybrid power system under Simulink to meet the energy needs of dwellings in the south of Algeria. The Enercon E40 wind turbine model with a rated power of 500 kW was selected. Simulations were performed for four sites, namely Tinfouye, Belkbir, Tabelbala and Tindouf using daily wind data ranging between 2004 and 2018. The results indicated that Tindouf has a high mean speed of 5.57 m/s at 10 m, resulting in a power density of 194 W/m2. However, a low average speed of 4.81 m/s is recorded at the site of Tabelbala. The maximum energy production is recorded at Belkbir reaching 4183.96 MWh/year with 0.9141 C$/kWh. Therefore, a high-power density of 239 W/m² was noted in Tabelbala. In the environmental analysis, Belkbir was found to have the highest avoided carbon dioxide (CO2) emission rate of 1829.64 tons CO2/kWh.

Multi-objective task scheduling method for cyber–physical–social systems in fog computing

Cyber–physical–social systems refer to new systems that involve a large number of Internet of Things (IoT) devices connected through an interconnected network. These systems gather data for various services such as transportation, energy, healthcare, etc. This data is then transmitted to the cloud layer for storage, processing, and access. To handle the significant workload offloaded from resource-constrained IoT devices without latency or bandwidth issues, a technology called fog computing has emerged as an intermediary layer between the cloud and IoT devices. The quality of service (QoS) provided by fog computing relies on efficient task scheduling to optimize energy consumption and maximum execution time. This task scheduling problem is known to be NP-hard and cannot be solved with high precision in a reasonable time using traditional techniques or existing metaheuristic-based task schedulers. Therefore, this study proposes a new multi-objective task scheduling approach based on a modified marine predators algorithm (MMPA) to simultaneously minimize energy consumption and make-span under the Pareto optimality theory. This variant is named the multi-objective MMPA (M2MPA). M2MPA enhances the performance of the MPA by incorporating the polynomial crossover operator to improve its exploration operator and the adaptive CF parameter to enhance its exploitation operator. The effectiveness of M2MPA is evaluated using eighteen tasks with different scales (small, large, and medium) and heterogeneous workloads assigned to two hundred fog devices with varying processing speeds. Finally, M2MPA is compared with six well-established techniques using various performance indicators, including carbon dioxide emission rate, flowtime, make-span, and energy consumption. The experimental findings demonstrate the substantial superiority of M2MPA over all competing algorithms across different performance indicators and the Wilcoxon rank-sum test. Quantitatively, M2MPA achieves an average make-span of 10.095, average energy consumption of 3.77E+06, average flowtime of 8.39E+03, and average carbon dioxide emission rate of 8.88E+06.

Assessing the bias and uncertainties in the aircraft mass balance technique for the determination of carbon dioxide emission rates

Urban areas are the major sources of greenhouse gas emissions but also leaders in emission reduction efforts. Appropriate techniques to quantify emissions and any potential reductions over time are necessary to effectively inform these mitigation efforts. The aircraft mass balance experiment (MBE) is an established technique used for such a purpose. In this work, we use a series of 55 MBEs downwind of power plants to assess the technique’s bias and precision. In addition, we investigate what factors drive the absolute error, determined as the absolute difference between observed and reported emission rates, in individual experiments using multilinear regressions. Power plants are required to monitor their carbon dioxide emissions with an hourly resolution, and these publicly available reported emissions can be directly compared to the mass balance estimates as a pseudo-known release. To quantify the bias we calculated the mean error, which was 10 ± 240 Mg·h−1 (1σ), regressed mass balance emission rates against reported emission rates to yield a slope of 0.967 ± 0.062, and compared the sum across all mass balance emission rates, 31,000 ± 1,000 Mg·h−1, to the sum across all reported emissions, 30,660 ± 740 Mg·h−1. All three of these approaches suggest no systematic bias. Then to quantify the precision for individual determinations we calculated the slope of a regression between the standard deviation across repeated MBEs and the corresponding average emission rate, which is 30.7% ± 6.7%. The main drivers of the absolute error were sparse sampling of the plume, poor horizontal and vertical mixing of the plume, and smaller signal-to-noise ratios. Quantifying the capabilities of this technique provides context for previous analyses and allows stakeholders and researchers to make informed decisions when choosing quantification methods. Identifying the factors that drive the absolute error also allows us to adjust flight design to minimize it and potentially improve uncertainty estimates.

Carbon loss and emissions within a permafrost collapse chronosequence

Permafrost carbon release is potentially the largest terrestrial feedback contributing to climate change. However, the changes in carbon release caused by the abrupt thawing of permafrost and their controlling factors remain largely unknown. Here, we measured soil organic carbon (SOC), total nitrogen (TN) concentrations, and carbon dioxide (CO2) and methane (CH4) emission rates among seven permafrost collapse features over 3 years in the northern Qinghai-Tibetan Plateau (QTP). The results showed soil carbon and nitrogen loss caused by permafrost collapse ranged from − 12% to 28% and − 1% to 38%, respectively. We found there was a nonlinear relationship between soil carbon loss and permafrost collapse chronosequence. Permafrost collapse significantly reduced ecosystem respiration (Reco) and weakened carbon sinks. The net ecosystem exchange (NEE) decreased from − 2.59 to − 0.21 µmol CO2 m−2 s−1. The Reco and NEE values showed no significant changes over time after the initial permafrost collapse. In contrast, the CH4 fluxes increased over time following permafrost collapse, and the CH4 fluxes significantly increased 2 to 10 times in the exposed area compared with that in the control area. Soil temperature, moisture, and nutrient availability exerted the most controls over the carbon emission during permafrost collapse. This study provides the patterns of carbon loss and emissions in different permafrost collapse landscapes, which will provide deep insights and reliable data for future prediction of the abrupt thawing of permafrost-carbon feedback.

Targeted Dissemination of Incident Information With Combinatorial Traffic-Communication Optimization

The dissemination of traffic incident information (TII) will greatly help to decrease fuel consumption and congestion under future Internet of Vehicles (IoV) environments. Compared with the current semi-targeted dissemination strategies of TII that focus on communication performance, we propose a complete targeted-dissemination strategy by jointly considering the impact of the dissemination on the route planning of connected vehicles and the communication performance of information dissemination in the IoV environment. This strategy further alleviates the considerable challenges caused by the increasing number of vehicles and limited radio resources in dissemination, while reducing the additional fuel consumption caused by excessive and meaningless dissemination by selectively distributing traffic information to connected vehicles. Specifically, the proposed strategy consists of a radio resource allocation strategy guaranteeing communication quality and a traffic-influencing targeted dissemination strategy selecting the targets. Simulation results validate the effectiveness of the proposed strategy in ensuring communication performance, reducing total cost, and decreasing the carbon dioxide emission rate.

Understanding the Impact of the Intercropping System on Carbon Dioxide (CO2) Emissions and Soil Carbon Stocks in Limpopo Province, South Africa

Understanding the carbon dioxide emission rates under different agricultural practices is a critical step in determining the role of agriculture in greenhouse gas emissions. One of the challenges in advocating for an intercropping system as a sustainable practice in the face of climate change is the lack of information on how much CO2 is emitted by the system. A factorial randomized complete block design study was set up at two distinct agroecological locations (Syferkuil and Ofcolaco) in the Limpopo Province of South Africa to investigate carbon dynamics in sorghum-cowpea intercropping and sole cropping system over two seasons. Intercropping system emitted less CO2 compared to sole cropping system. In 2018/19 at Syferkuil and 2020/21 at Ofcolaco, intercropping systems emitted 11% and 19% less CO2, respectively, than sole cropping systems. In both agroecological regions, low cowpea density consistently resulted in higher CO2 emissions than high density. During the 2018/19 cropping season, sorghum emitted more CO2 of 5.87 t·ha−1 than cowpea with 5.14 t·ha−1 in a sole cropping system at Syferkuil. Cowpea, on the other hand, emitted more CO2 of 6.5 t·ha−1 and 10.18 t·ha−1 than sorghum during the 2020/21 cropping season at Syferkuil and Ofcolaco, respectively. Furthermore, intercropping improved the carbon emission efficiency (CEE) of the individual crops in the system. The treatments used in the intercropping and sole cropping systems had a significant impact on the strength of the relationship between carbon stocks and CEE. Our results revealed that sorghum-cowpea intercropping system at a relatively higher cowpea density in a no-till system reduces the amount of CO2 lost to the atmosphere. The system can thus, be promoted as one of the sustainable farming practices to reduce emissions and improve carbon storage in the soil.

Emission rate of carbon dioxide by older adults while sleeping

Humans emit carbon dioxide (CO2) as a product of their metabolism. No measurements of CO2 emission rates (CERs) of elderly sleeping people have yet been reported. This study performed such measurements and examined the possible mechanisms impacting CERs. Sixteen participants (8 males) aged ≥65 years old slept alone for a whole night under each of the four conditions in a 2 × 2 design: air temperatures of 27 °C and 30 °C and ventilation rates of 5 m3/h per person and 28 m3/h per person (resulting in an average indoor CO2 concentration of about 1200 ppm and 760 ppm, respectively). Physiological responses were recorded during sleep. Indoor parameters including CO2 concentration were continuously measured during and after sleep period. The CERs were calculated using a mass-balance model. The results show that the average CER was 9.0 ± 1.6 L/h per person. It was ca. 20% higher for males than for females, probably due to higher body mass, body surface area, and longer time awake during sleep. Compared with 27 °C, the CER was about 10% higher at 30 °C probably due to longer time awake and higher heart rate and skin temperature at this condition. No significant differences in CERs were observed between the two ventilation rates. The CERs measured in the present study for elderly are slightly lower than recently reported for young adults and 10–12 year old children. They all provide information required for estimating ventilation rates in bedrooms assuming that the ventilation is achieved with clean outdoor air.

Features of the self-restoration of the oil-contaminated peat-bog soil – a field study

The features of self-restoration processes of the oligotrophic peat-bog soil disturbed by crude oil pollution were studied. Soil contamination was carried out in field long-term experience. The key soil self-recovery indicators were: (1) the rate of carbon dioxide emission by the soil, which quantitatively characterizes the mineralization of petroleum hydrocarbons by microorganisms; (2) content of petroleum products. The microorganisms of the studied soil were characterized by low resistance to the toxic effects of oil: during the first three years of the experiment, the respiration of oil-contaminated soils was significantly lower than in pure soil. Restoration of microbial respiration to the control level and its further intensive growth occurred after 4-5 years of the experiment only in soils with low oil doses: 0.3 and 0.6 l m-2. In time, this coincided with the maximum rate of oil decomposition, which indicates the microbial nature of its utilization. The respiration of soil with oil high doses (1.8 and 3.0 l m-2) remained significantly lower than in pure soil throughout the entire experiment. At the same time, the amount of oil products in these samples markedly decreased. Oil degradation in these variants could occur due to the activity of anaerobic bacteria or abiotic processes.

CPP 추진 선박의 운전 모드에 따른 기관성능 및 배기배출물 특성에 관한 연구

The engine performance and exhaust gas emissions of a ship equipped with a controllable pitch propeller and a medium-sized medium-speed diesel engine were compared according to the engine load in constant and combined mode. The cylinder pressure diagram, indicated mean effective pressure, specific fuel consumption, navigation distance to unit fuel consumption and air ratio were used to evaluate the engine performance and the emission rates of carbon dioxide, carbon monoxide, nitrogen oxides and smoke concentration were used to evaluate the exhaust gas emissions. According to the results, the engine performance and exhaust emission characteristics under a high load were similar in constant mode and combined mode. In the case of operating an engine under medium load, it was possible to reduce the fuel consumption and carbon dioxide emission rate by setting the operation mode of a controllable pitch propeller to the combined mode, but the emission rate of nitrogen oxides was slightly increased. It is thought that results of this study can provide the reference data that can reduce the carbon dioxide emission to prevent global warming and that can also improve the engine performance when selecting the operating mode of a controllable pitch propeller on the ship with a controllable pitch propeller equipment.

İNŞAAT ATIKLARININ İKLİM DEĞİŞİKLİĞİ ÜZERİNE ETKİLERİ: DAHA ÇEVRECİ BİR İNŞAAT SEKTÖRÜ MÜMKÜN MÜ?

Due to the increasing population, the rapid consumption of natural resources has revealed the necessity of protecting nature from people. Increasing building stock due to population growth has triggered climate change. The energy and natural resources consumed during production in the construction sector have created important environmental problems such as global warming and climate change in the sector. Greenhouse gas emissions caused by construction materials can be considered as one of the main causes of climate change problems and emphasizes the necessity of considering environmental effects. Greenhouse gas is one of the most important factors affecting the ecological environment and climate change, as it is one of the gases with the highest carbon dioxide emission rate. Concrete and steel used in the construction industry are among the materials that have a negative impact on climate change. This study revealed the effects of waste materials used in the construction industry on the problem of climate change and the importance of promoting the efficient use of energy resources for the management of this problem. In addition, this study emphasized the importance of focusing on sustainable structures in order to leave a cleaner and healthier environment for future generations, and that priority should be given to developing environmentally friendly materials.

Optimal Parameters of Gas Drainage and Carbon Dioxide Inerting Technology and Its Application in a High Gassy and Spontaneous Combustion Mine.

In the process of coupling disaster prevention and control of gas and coal spontaneous combustion in goaf, there is a great contradiction between the gas drainage and carbon dioxide inerting technology. The key performance indexes are put forward to solve the coupling disaster, such as the air quantity of the intake airway (A), the gas drainage rate (B), the carbon dioxide injection rate (C), and the injection depth (D). Using the numerical simulation method and the orthogonal test of four factors and three levels, we establish the coupling disaster model of the no. 7436 working face in the Kongzhuang coal mine. Using a combination of the relative membership degree method and range analysis, the optimal level of each factor is determined, which is AIIBIIICIIDII. Furthermore, the distribution law of the airflow field is obtained under the conditions of different gas drainage rates and carbon dioxide injection rates. The results show that the gas concentration decreases with an increase in gas drainage in the upper corner, but it has little impact on the width of the oxidation zone. The gas concentration can be reduced to 1%, while the gas drainage rate is higher than 35 m3/min. With an increase in gas injection rate, the carbon dioxide emission rate increases in the upper corner, but the width of the oxidation zone decreases. Also, the gas injection rate should be less than 800 m3/h. Moreover, with an increase in injection time in the upper corner during the injection process, the carbon dioxide and gas concentrations increase, and the maximum carbon dioxide concentration is 1.3%, and the maximum gas concentration is 0.42%, which is consistent with the results of numerical simulations.

Recent developments in CO 2 capture, utilization, related materials, and challenges

Anthropogenic activities including the combustion of fossil fuels have led to a dramatic increase in the rate of carbon dioxide (CO2) emission in the last three decades. Since fossil-based fuels are still the predominant energy source for this century, CO2 is a colossal problem. It is emitted as a consequence of combustion and human activities and is a major greenhouse gas (GHG) that significantly contributes to climate change and global warming, making CO2 emission a worldwide problem. The Intergovernmental Panel on Climate Change (IPCC) has proposed a 45% decrease in anthropogenic CO2 emissions by 2030, with a target of “net-zero” CO2 emissions by 2050. Despite its harmful effects, CO2 has the potential to be used for a wide range of different industrial needs, after its capture. CO2 capture technologies are still in the early stage of development because of economic and technological issues. However, in the future, carbon capture and related application technologies and methods may become easier and more accessible due to the new developments in the materials synthesis, strategies and skills and inexpensive utilization, and functioning cost of the employed methods. Furthermore, carbon capture system (CCS) might improve the recent power plan system properties. Concerning climate change, carbon capture is deemed as a promising solution to prevent CO2 emissions. CO2 capture, storage, and utilization are garnering intensive interest from scientists worldwide. This review paper identifies and gave particular attention to the literature on the recent CO2 capture technologies, for example, adsorption, absorption, membrane, and algae-based separation techniques for pre-combustion, oxy-fuel combustion, and post-combustion periods. Aside from all of these capture technologies, the utilization and application of captured CO2 in various industrial fields such as solvents, chemicals, and fuels are evaluated.

Statistical and stochastic feasibility studies of potential liquid organic hydrogen carriers in a membrane reactor for simultaneous hydrogen storage and production: Technical, economic, and environmental aspects

With a global trend of transition to the hydrogen-based energy system, the importance of improved systems of hydrogen production and transportation is emphasized. Especially, liquid organic hydrogen carrier is introduced due to its significant advantages when it is employed as a hydrogen energy carrier. In this study, the comprehensive preliminary feasibility study in technical, economic, and environmental aspects for hydrogen production systems using several promising systems of dodecahydro-N-ethycarbazole, Perhydro-dibenzyltoluene, methylcyclohexane, and methanol in a membrane reactor is conducted to investigate its potential to be alternative hydrogen production and transportation. With process simulation using Aspen Plus® based on detailed reaction kinetics for dehydrogenation of each dehydrogenation system and steam reforming of methanol, technical performance in terms of production rate is revealed. In addition, unit hydrogen production costs and key economic parameters for each system at various scales are estimated and compared by itemized cost estimation. Furthermore, realistic uncertainty analysis reflecting detailed distributions of each economic parameter obtained by various regression types of triangular, Epsilon skew normal, Birnbaum-Saunders, and Rayleigh and environmental assessment using SimaPro® are conducted revealing possible ranges of unit hydrogen production cost and carbon dioxide emission rate.

Transforming conventional distillation sequence to dividing wall column: Minimizing cost, energy usage and environmental impact through genetic algorithm

This work aims at proposing a multi-objective optimization (MOO) strategy for dividing wall column (DWC) that can provide energy-efficient and cost-effective operation for ternary feed mixtures compared to its conventional two-column distillation sequence. Today, DWC has emerged as a promising industrially relevant thermally integrated configuration. If its design and operating conditions are truly optimized, the cost can further be reduced. At the same time, it is also equally, if not more, important for a distillation column to consider its product purity, productivity and environmental standard. With this, a multi-objective genetic algorithm based optimization framework is formulated to include all these crucial factors. Due to the presence of various conflicting objectives, multiple optimal solutions are inevitable. With this, the proposed optimization strategy works with the three steps: (i) sensitivity analysis to find the decision variables, (ii) a non-dominated sorting genetic algorithm (NSGA-II) to generate multiple optimal solutions, and (iii) the technique for order of preference by similarity to an ideal solution (TOPSIS) method to select one optimal point. Further, the Aspen Plus flowsheet simulator is integrated with MATLAB to simultaneously perform extensive simulation and optimization. This potential integration leads to reducing the total run time substantially. Finally, two industrially relevant ternary systems, namely Benzene-Toluene-Xylene (BTX) and Benzene-Toluene-Ethylbenzene (BTE) are used to illustrate the proposed strategy for investigating the performance improvement of the DWC over its conventional distillation sequence (CDS). Simulation results show that the DWC can secure up to 23% savings in capital cost, 45% in operating cost and reduce the rate of carbon dioxide emission by about 45%.

马尾松幼苗根系和光合碳供应对土壤性质变化和温室气体排放的驱动作用

PDF HTML阅读 XML下载 导出引用 引用提醒 马尾松幼苗根系和光合碳供应对土壤性质变化和温室气体排放的驱动作用 DOI: 10.5846/stxb202008012004 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家重点研发计划(2017YFC0505503)；国家自然科学基金面上项目(31370627) Root input and photosynthetic carbon supply effect on soil properties and greenhouse gases release of Pinus massoniana seedling Author: Affiliation: Fund Project: The National Key Technologies R&D Program of China 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:森林植被受全球气候变化、森林经营活动及病虫害等多种干扰,导致林地光合碳供应水平及根系输入量发生变化。在此背景下,土壤性质及土壤温室气体排放的响应及其机理是预测森林碳汇功能变化及森林可持续经营的重要依据。以2年生马尾松盆栽苗为对象,通过单株/盆和3株/盆栽植密度控制根系输入量、通过环割和截干控制光合碳向地下的供应能力,模拟森林植被干扰导致的根系输入量及光合碳供应变化对土壤理化性质、微生物群落结构及温室气体排放的影响。结果表明,苗木根系非结构性碳水化合物(TNC)含量和氮含量比单株/盆低;3株/盆的土壤速效氮含量比单株/盆低,土壤革兰氏阳性菌、厌氧菌、放线菌及丛枝菌根真菌丰富度均比单株/盆显著增加,3株/盆的土壤二氧化碳(CO2)排放速率较高,但土壤氧化亚氮(N2O)排放速率差异不显著。无论是单株/盆还是3株/盆,环割和截干处理后,根系生物量、根系长度及表面积均比对照显著下降;根系TNC含量显著下降。土壤和根系氮含量都有增加趋势;土壤微生物生物量碳(SMBC)含量降低,而土壤微生物生物量氮(SMBN)则提高。环割和截干后,土壤中各种微生物组成丰富度均有下降趋势,土壤CO2排放速率显著下降,土壤N2O排放速率则显著提高。根系输入量及光合碳供应对土壤细菌和真菌含量均有显著影响,土壤细菌含量与根系生物量、SMBC和SMBN显著正相关;土壤真菌含量与土壤温度显著负相关,与根系生物量、SMBC和SMBN显著正相关。相关分析表明,土壤CO2排放通量与土壤温度、土壤湿度及根系生物量显著正相关,与土壤硝态氮显著负相关;土壤N2O排放通量与土壤温度和土壤湿度显著正相关。以上研究表明,根系输入量与地上光合碳供应共同作用,改变土壤理化性质及微生物环境,进而影响土壤温室气体排放。 Abstract:Forest vegetation is affected by climate change, forest management activities, and diseases and pests, which can lead to changes in photosynthetic carbon supply, root input of forest land, composition of soil microbial community, and soil greenhouse gases emission. These changes and their underlying mechanisms are the basis for modelling change of forest ecological functions and for managing forest scientifically. Here, we studied level of root input of 2-year-old potted seedlings of Pinus massoniana under two densities, single-plant/pot and 3-plants/pot, and under two disturbance treatments, ring-barking and stem-severing to stop carbon transport to the root system. We aimed to simulate the effects of changes in root input and photosynthetic carbon supply on soil physical and chemical properties, microbial community structure and greenhouse gas emission under various conditions. Our results showed that the total nonstructural carbohydrate (TNC) and nitrogen in seedling roots were lower in 3-plants/pot treatment than in single-plant/pot treatment. The content of soil available nitrogen in 3-plants/basins was lower than that in single-plant/pot. In contrast, richness of soil Gram-positive bacteria, anaerobic bacteria, actinomycetes and arbuscular mycorrhizal fungi were higher in 3-plants/pot treatment than in single-plant/pot treatment. Further, the emission rate of soil carbon dioxide (CO2) was higher in 3-plants/pot treatment than in single-plant/pot treatment. Planting density had no significant effects on emission rate of soil nitrous oxide (N2O). Both the ring-barking and stem-severing treatments decreased the root biomass, root length, root surface and root TNC content in both single-plant/pot and 3-plants/pot treatments. Both the ring-barking and stem-severing treatments increased the content of nitrogen in soil and roots, the content of soil microbial biomass nitrogen (SMBN), and emission rate of soil N2O, but decreased the content of soil microbial biomass carbon (SMBC), the richness of soil microbial and the emission rate of soil CO2. Root biomass input and photosynthetic carbon supply have significant effect on soil bacterial and fungal contents. Soil bacterial contents were positively correlated with root biomass, SMBC and SMBN. Soil fungal content was negatively correlated with soil temperature, positively correlated with root biomass, SMBC and SMBN. Correlation analysis showed that soil CO2 emission flux was positively correlated with soil temperature, soil humidity and root biomass, while negatively correlated with soil nitrate nitrogen; soil N2O emission flux was positively correlated with soil temperature and soil humidity. The results suggest that root input and photosynthetic carbon supply work together to change soil physical and chemical properties and microbial environment, thus contribute to changes in the emissions rate of soil greenhouse gases. 参考文献 相似文献 引证文献

Carbon Dioxide Storage Potential in Malaysian Sandstone Aquifer: An Overview

Carbon dioxide (CO2) emission rate from energy industries in Malaysia has increased exponentially in these few years. Based on this alarming increment of CO2 emission rate from previous data, carbon dioxide sequestration in deep saline aquifer has been identified as one of the way to reduce and overcome the increment of CO2 emission rate in Malaysian atmosphere. Malaysian geology consists of enormous amount of deep saline aquifer which most of the aquifer material is sandstone. Malay Basin has been identified as the most potential basin for CO2 sequestration in Malaysia by previous researchers. There are four sites in Malay Basin which has potential to be CO2 sequestration site such as Jerneh, Dulang, Tangga and Semangkok because they contain the formation of fine-grained sandstone, mudstone and coal properties. This paper aims to discuss CO2 storage potential in Malaysian sandstone aquifer particularly Malay Basin in terms of potential injection location, properties of Malaysian sandstone aquifer, available technologies of injection, injection parameter as well as issues and challenges of carbon sequestration implementation in Malaysia.