Prenatal interventions for fetal lung lesions

The widespread availability of high resolution ultrasound equipment and almost universal routine anatomy scanning in all pregnant women in the developed world has lead to increased detection of abnormalities in the fetal thorax. Already in the 1980s, large pleural effusions and significant macrocystic lesions in the fetus were easily detected on ultrasound. However, smaller lung tumours were often missed. Nowadays, fetal medicine centres receive many referrals for evaluation of fetal lung lesions, of which the most common are congenital cystic adenomatoid malformation and bronchopulmonary sequestration. Almost invariably, both the parents and the referring physicians experience anxiety after detection of large lung masses in the fetus. However, the vast majority of the currently detected fetal lung lesions have an excellent prognosis without the need for prenatal intervention. In the small group of fetuses in which the prognosis is poor, almost exclusively those with concomitant fetal hydrops and cardiac failure, several options for fetal therapy exist, often with a more than 50% survival rate. Indications, techniques, complications and outcomes of these interventions will be described in this review. Copyright © 2011 John Wiley & Sons, Ltd.     

How many samples are required? Evaluating a model for verification of carbon sequestration in a hybrid poplar buffer strip

A model is developed to predict annual and total above-ground carbon storage within a hybrid poplar stream buffer. The regression model predicts tree wet weight based upon circumference at breast-height (137 cm) with an r-square value of 0.9922. Carbon storage in above-ground biomass is estimated to be 3.57 to 3.71 metric tons per hectare, with a measured annual increment of 0.92 to 1.37 metric ton per hectare per year. The variability of carbon storage within this biological system, including soil organic matter, is explored, and the number of samples required to achieve a desired level of statistical certainty are predicted. As has been investigated previously for other biological systems (Garten and Wullschleger, 1999), the study shows that a prohibitively large number of samples must be taken in order to achieve high degrees of certainty about mean carbon storage values. The study also shows, however, that mean values with somewhat greater uncertainties can easily be achieved with much smaller sample sizes. Thus carbon sequestration verification might be accomplished cost-effectively if the degree of certainty required is not unrealistically high for highly variable natural systems.     

The Potential of Soil Carbon Sequestration Through Improved Management Practices in Norway

The study was conducted to assess the potential of Norwegian agricultural ecosystems to sequester carbon (C) based on the data from some long-term agronomic and land use experiments. The total emission of CO₂ in Norway in 1998 was 41.4 million metric ton (MMT), of which agriculture contributed only 0.157 MMT, or <0.4% of the total emissions. With regards to methane (CH₄) and nitrous oxide (N₂O) gases, however, agricultural activities contributed 32.5% and 51.3% of their respective emissions in Norway. The soil organic carbon (SOC) losses associated with accelerated soil erosion in Norway are estimated at 0.475 MMTC yr^–1. Land use changes and soil/crop management practices with potential for SOC sequestration include conservation tillage methods, judicious use of fertilizers and manures, use of crop residues, diverse crop rotations, and erosion control measures. The potential for SOC sequestration is 0.146 MMTC yr^–1 for adopting conservation tillage, 0.011–0.035 MMTC yr^–1 for crop residue management, 0.026 MMTC yr^–1 for judicious use of mineral fertilizer, 0.016–0.135 MMTC yr^–1 for manure application, and 0.036 MMTC yr^–1 for adopting crop rotations. The overall potential of these practices for SOC sequestration ranges from 0.591 to 1.022 MMTC yr^–1 with an average value of 0.806 MMTC yr^–1. Of the total potential, 59% is due to adoption of erosion control measures, 5.8% to restoration of peat lands, 21% to conversion to conservation tillage and residue management, and 14% to adoption of improved cropping systems. Enhancing SOC sequestration and improving soil quality, through adoption of judicious land use and improved system of soil and crop management, are prudent strategies for sustainable management of soil, water and environment resources.Readers should send their comments on this paper to: bhaskarn ath@aol.com within 3 months of publication of this issue.     

Blue carbon in human-dominated estuarine and shallow coastal systems

Estuarine and shallow coastal systems (ESCS) are recognized as not only significant organic carbon reservoirs but also emitters of CO₂ to the atmosphere through air–sea CO₂ gas exchange, thus posing a dilemma on ESCS’s role in climate change mitigation measures. However, some studies have shown that coastal waters take up atmospheric CO₂ (C_atm), although the magnitude and determinants remain unclear. We argue that the phenomenon of net uptake of C_atm by ESCS is not unusual under a given set of terrestrial inputs and geophysical conditions. We assessed the key properties of systems that show the net C_atm uptake and found that they are often characteristic of human-dominated systems: (1) input of high terrestrial nutrients, (2) input of treated wastewater in which labile carbon is highly removed, and (3) presence of hypoxia. We propose that human-dominated ESCS are worthy of investigation as a contributor to climate change mitigation.     

Influence of SO2 in incineration flue gas on the sequestration of CO2 by municipal solid waste incinerator fly ash

The influence of CO2 content and presence of SO2 on the sequestration of CO2 by municipal solid waste incinerator(MSWI) fly ash was studied by investigating the carbonation reaction of MSWI fly ash with different combinations of simulated flue gas.The reaction between fly ash and 100% CO2 was relatively fast;the uptake of CO2 reached 87g CO2/kg ash,and the sequestered CO2 could be entirely released at high temperatures.When CO2 content was reduced to 12%,the reaction rate decreased;the uptake fell to 41g CO2/kg ash,and 70.7% of the sequestered CO2 could be released.With 12% CO2 in the presence of SO2,the reaction rate significantly decreased;the uptake was just 17g CO2/kg ash,and only 52.9% of the sequestered CO2 could be released.SO2 in the simulated gas restricted the ability of fly ash to sequester CO2 because it blocked the pores of the ash.     

废弃混凝土中钙离子的提取实验研究

废弃混凝土间接碳酸化封存CO2的重要一步是将Ca2+从混凝土中提取出来。论文对废弃混凝土中Ca2+的提取进行了研究,主要考察了提取溶剂、混凝土粒径、温度和固液比等对Ca2+提取过程的影响。对不同的提取溶剂进行了比较,发现HNO3作为溶剂时Ca2+提取率最高,其次为CH3COOH、HCOOH和H2SO4。减小混凝土粒径可有效提高Ca2+提取率。对粒径小于0.15 mm的混凝土,Ca2+提取率随温度升高而增大,其最佳固液比为40 g/L。粒径大于0.25 mm时,最佳固液比为20 g/L,温度的影响明显减弱。将Ca2+提取实验结果与XRD、SEM表征结合,发现废弃混凝土提取过程中SiO2惰性层的出现是限制Ca2+提取率进一步提高的重要原因。     

黑炭分解的影响因素及其激发效应机制研究进展

黑炭是生物质和化石燃料不完全燃烧形成的富含C的固体有机材料,广泛存在于环境中,具有长期存储C的潜力,在全球C循环中具有重要作用,并且被作为减缓气候变化的重要策略。然而,当前我们有关黑炭分解及其激发效应机制的知识是有限的。因此,需要全面深入了解影响黑炭分解的控制因素及其激发效应的可能机制。本文首先对黑炭分解研究进行综合分析,详细评述了气候/培养条件,土壤特征、黑炭性质以及干扰因素对黑炭分解的影响及其机理。其次,介绍了黑炭激发效应的测定方法,重点综述了黑炭激发效应大小与方向的影响因素及其可能机制。最后,指出了黑炭分解及其激发效应研究的不足,并提出了未来研究需要关注的问题和方向,以期为将黑炭融入到土壤有机质和生态系统模型提供借鉴。     

生物炭对滨海湿地盐碱土壤碳氮循环的影响

滨海湿地盐碱土壤在全球碳氮循环及调节气候变化中起着重要作用。环境友好型土壤改良剂生物炭（Biochar,BC）在缓解气候变化和促进农业可持续发展方面前景巨大。然而,现有研究多关注BC对滨海湿地盐碱土壤中温室气体排放及土壤氮素流失的影响,缺乏其对滨海湿地盐碱土壤碳氮循环的深入研究和系统总结。本文综合分析了施用BC对滨海湿地盐碱土壤植被碳库、有机碳库、有机碳矿化及生物固氮、硝化、反硝化、矿化、氨损失等碳氮循环过程的影响和可能机制。指出未来应关注长期野外研究,利用宏基因组等现代分子生物技术,阐明BC对土壤碳氮循环影响的分子生物学机制,以期为滨海湿地生态系统的修复与功能保育提供理论依据。     

生物炭技术缓解我国温室效应潜力初步评估

热解制备的生物炭在实现了将植物吸收的大气CO2封存在土壤中的同时,还将产生多重农业生产效应.在调查我国农林废弃物资源可利用潜力的基础上,利用生命周期评价(life cycle assessment,LCA)方法对热解生物炭技术在缓解温室效应方面的潜力进行了初步评估.研究表明,我国每年可供生物炭生产的农林生物质资源总量为6.04×108t;温室效应净潜力(以CO2e计,CO2e为CO2当量)为5.32×108t,相当于每t原料可封存0.88 t.在整个温室效应潜力中,贡献最大的是大气CO2以生物炭形式在土壤中的封存,约为73.94%,其次是副产物可更新能源生产所产生的温室效应潜力,占总潜力的23.85%.由此可见,以农林废弃生物质资源为原料热解制备生物炭的技术对于缓解我国严峻的温室气体排放压力具有巨大的潜力.     

关中地区农田土壤有机碳固存速率及影响因素：以陕西武功县为例

以武功县为例,通过计算农田土壤碳储量及固碳速率,明确关中地区农田土壤有机碳动态变化的规律,进而揭示农田土壤有机碳与自然因素、人为因素的关系.结果表明:①80%的样点0～20 cm农田土壤有机碳含量在8.0～12.0 g.kg-1之间,总体上呈现正态分布.②武功县2011年0～20 cm农田土壤有机碳密度为26.3 t.hm-2,低于全国农田耕层土壤有机碳密度平均水平(33.45 t.hm-2).近30年农田土壤固碳速率为71.3 kg.(hm2.a)-1,近5年农田土壤固碳速率为480 kg.(hm2.a)-1,近期固碳速率高于全国农田耕层土壤平均固碳速率[380.78 kg.(hm2.a)-1].③在半湿润平原地区,土壤有机碳含量主要受土壤类型、地貌类型、有机肥投入的影响,其中土壤类型可解释30.2%的有机碳变异性,地貌类型可解释37.7%,有机肥可解释32.1%.综合分析表明,武功县农田土壤有机碳密度在过去30 a间呈增加趋势,这可能与化肥的施用和秸秆还田有关,具体有多大的影响程度还需进一步研究.