城市温室气体排放清单编制研究进展

温室气体排放清单是目前最常用的城市碳排放核算方法,有助于在大尺度上了解城市不同行业或部门的温室气体排放情况.然而,中国城市温室气体清单研究刚刚起步,研究成果还不多,尚缺乏系统、规范的城市温室气体研究方法和指标体系.概述了城市温室气体排放清单的主要参考编制方法,介绍了国内外城市温室气体清单的编制情况,对目前城市温室气体清单编制的特点进行了分析,总结了城市温室气体清单与国家温室气体清单在关键排放源、编制模式、方法体系等方面的差异;在此基础上结合我国城市实际,对适合中国城市的温室气体清单编制方法进行了探索,并针对清单编制过程中存在的具体问题提出了建议;最后对未来城市温室气体清单的发展趋势进行了展望,以期为中国温室气体清单编制及研究提供借鉴.     

再生稻田温室气体排放特征及碳足迹

研究中国东南区域不同稻作方式对水稻生产过程中稻田温室气体排放特征及其碳足迹的影响,对促进水稻可持续生产有重要意义。本研究以当前推广的常规稻‘佳辐占'和杂交中稻‘甬优2640'为材料,构建4种适合福建不同生态类型区的稻作模式: 1) 双季稻,早稻和晚稻均种植佳辐占(D-J);2) 早熟再生稻,头季稻和再生季稻均种植佳辐占(R-J);3) 中熟再生稻,头季稻和再生季稻均种植甬优2640(R-Y);4) 单季晚稻,与中熟再生季稻同期抽穗的单季晚稻,种植甬优2640(S-Y)。采用密闭静态暗箱观测法和气相色谱法分别收集并检测稻田土壤温室气体排放量,借用生命周期法对不同稻作方式产生的直接和间接温室气体排放总量(即碳足迹)进行数据采集与比较分析。结果表明: 不同稻作方式稻田温室气体排放特征均表现为生育前期排放量较低,到孕穗期前后达到高峰后又下降,即全生育期呈前高后低的双峰曲线,其中早稻或头季稻达到的第1个峰值较相应晚稻或再生季稻的第2个峰值高。不同稻作模式稻田温室气体排放总量差异显著。各种植模式全球增温潜势(GWP)表现为:R-Y>D-J>S-Y>R-J,温室气体排放强度(GHGI)表现为:D-J>S-Y>R-Y>R-J;与双季稻模式相比,佳辐占再生稻模式GWP和GHGI分别降低26.1%和14.1%;与同期抽穗的单季晚稻相比,甬优2640再生季稻稻田GWP和GHGI分别降低74.3%和56.7%。不同稻作模式下水稻单位产量碳足迹为0.38~1.08 kg CO₂-eq.·kg^-1,其中双季稻模式下最高,再生稻模式下甬优2640的单位产量碳足迹最低。不同稻作模式产生的碳足迹主要来源于CH₄,其贡献率高达44.2%~71.5%。可见,再生稻种植模式能显著降低水稻全球增温潜势和碳排放强度。选用高产低碳排放的水稻优良品种并配套科学栽培技术,是有效降低稻田CH₄排放量和碳足迹、促进再生稻生产可持续发展的关键。     

Well-to-wheel analysis on greenhouse gas emission and energy use with natural gas in Korea

Purpose

In Korea, natural gas is widely used as city gas, fuel for electricity generation, and fuel for transportation (e.g., city bus). However, the environmental impact associated with the use of natural gas in Korea has not been paid much attention to. In this study, well-to-wheel (WTW) analysis on the greenhouse gas (GHG) emissions and energy uses associated with natural gas in Korea was performed by considering every step from feedstock recovery to final use in the vehicle operation.

Methods

The raw data used in the analysis were mainly provided by Korean natural gas industry and related associations. The additional information, especially for the processes in foreign countries, was also collected by literature survey. We adopted the GREET (Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation) model as a base WTW analysis tool, which was developed by the U.S. Argonne National Laboratory. However, the WTW analysis on natural gas in Korea is far different from that of the U.S, because ~99 % of natural gas used in Korea is imported from the oversea countries in the form of liquefied natural gas (LNG). For this reason, detailed parameters in GREET were changed for Korean situation, and especially, significant modifications were made on liquefaction, LNG transportation and storage, and re-gasification processes.

Results and discussion

As a result of the analysis, the well-to-pump GHG emissions of city gas and compressed natural gas are calculated as 25,717–30,178 and 28,903–33,422 g CO₂ eq./GJ_{Fianl_fuel}, respectively. The WTW GHG emission of compressed-natural-gas-fueled city bus is calculated as 1,348–1,417 g CO₂ eq./km. These values are relatively larger than those of the U.S., because most of the natural gas used in the U.S. is transported by pipeline in a gaseous state, which typically takes less energy and associated GHG emissions, as compared to the import of LNG in Korea. Finally, sensitivity analysis is performed on the parameters, which have either range of values among various sources or uncertainties due to lack of accurate information.

Conclusions

The results show that further investigation on three parameters, i.e., CO₂ venting during natural gas processing, CH₄ leakage in Korea, and CH₄ leakage during recovery process, would be helpful to further improve overall accuracy of the analysis.     

Leachate treatment and greenhouse gas emission in subsurface horizontal flow constructed wetland

Organic and nitrogen removal efficiencies in subsurface horizontal flow wetland system (HSF) with cattail (Typha augustifolia) treating young and partially stabilized solid waste leachate were investigated. Hydraulic loading rate (HLR) in the system was varied at 0.01, 0.028 and 0.056 m³/m² d which is equivalent to hydraulic retention time (HRT) of 28, 10 and 5 d. Average BOD removals in the system were 98% and 71% when applied to young and partially stabilized leachate at HLR of 0.01 m³/m² d. In term of total kjeldahl nitrogen, average removal efficiencies were 43% and 46%. High nitrogen in the stabilized leachate adversely affected the treatment performance and vegetation in the system. Nitrogen transforming bacteria were found varied along the treatment pathway. Methane emission rate was found to be highest at the inlet zone during young leachate treatment at 79–712 mg/m² d whereas CO₂ emission ranged from 26–3266 mg/m² d. The emission of N₂O was not detected.     

Mycobacterium fortuitum and Mycobacterium chelonae biofilm formation under high and low nutrient conditions

The rapidly growing mycobacteria (RGM) are broadly disbursed in the environment. They have been recovered from freshwater, seawater, wastewater and even potable water samples and are increasingly associated with non-tuberculous mycobacterial disease. There is scant evidence that non-tuberculous mycobacteria (NTM) and RGM form biofilms. Therefore, an experimental system was designed to assess the ability of RGM to form biofilms under controlled laboratory conditions. A flat plate reactor flow cell was attached to either a high or low nutrient reservoir and monitored by image analysis over time. Two surfaces were chosen for assessment of biofilm growth: silastic which is commonly used in medical settings and high density polyethylene (HDPE) which is prevalent in water distribution systems. The results show that Mycobacterium fortuitum and M. chelonae formed biofilms under both high and low nutrient conditions on both surfaces studied. These results suggest that RGM may form biofilms under a variety of conditions in industrial and medical environments.     

Litter dynamics of low and high tannin sericea lespedeza plants under field conditions

Sericea lespedeza [Lespedeza cuneata (Dum. Cours) G. Don.] is a perennial legume with high polyphenol (tannin) concentration. The decomposition and nutrient release of sericea lespedeza residues with two tannin levels (high = 22% or low = 16%), which were either placed on the soil surface or buried at a depth of 5 cm were studied. An experiment was carried out at two sites for 2 yr. Litter mass loss and nutrient (N, P, K, Ca, Mg, Cu, Fe, Mn, Zn, B, Mo, Co) release were recorded. Litter mass loss was higher for the low-tannin residues and for those buried. From the beginning of the experiments, the C : N ratio was lower than 25 : 1 and N was mineralized for most of the studied cases; this means that N increased in availability to plants. The release of the rest of the studied nutrients was higher at the depth of 5 cm than on the soil surface and higher for low-tannin residues than for high-tannin. The observed accumulation of some nutrients in the first months presumably depended on microbial activity. The rate of release was higher for the macronutrients than for the micronutrients, with the exception of B, which had the same behaviour as the macronutrients. This revised version was published online in June 2006 with corrections to the Cover Date.     

Strain selection for pigeon pea Rhizobium under greenhouse conditions

Pigeon pea obtains N for growth by N₂ fixation although yield generally is not improved by either the inoculation of Rhizobium or by the application of N fertilizer in Puerto Rico. Sixteen strains ofRhizobium spp., different in geographical origin, were tested for N-fixing effectiveness, determined from comparisons with uninoculated controls, N controls and the standard strain 176A22. Inoculated treatments showed significant differences in nodulation, plant dry weight and %N. Several strain x plant combinations had higher N content than the N treatment, reflecting the ubiquity of effective strains and the possible lack of response of pigeon pea to inoculation or N fertilization. Strains superior in N₂ fixation were selected for testing for symbiotic effectiveness under field conditions.     

Arbuscular mycorrhizas enhance nutrient uptake in different wheat genotypes at high salinity levels under field and greenhouse conditions

Since most experiments regarding the symbiosis between arbuscular mycorrhizal (AM) fungi and their host plants under salinity stress have been performed only under greenhouse conditions, this research work was also conducted under field conditions. The effects of three AM species including Glomus mosseae, G.?etunicatum and G.?intraradices on the nutrient uptake of different wheat cultivars (including Roshan, Kavir and Tabasi) under field and greenhouse (including Chamran and Line 9) conditions were determined. At field harvest, the concentrations of N, Ca, Mg, Fe, Cu, and Mn, and at greenhouse harvest, plant growth, root colonization and concentrations of different nutrients including N, K, P, Ca, Mg, Mn, Cu, Fe, Zn, Na and Cl were determined. The effects of wheat cultivars on the concentrations of N, Ca, and Mn, and of all nutrients were significant at field and greenhouse conditions, respectively. In both experiments, AM fungi significantly enhanced the concentrations of all nutrients including N, K, P, Ca, Mg, Mn, Cu, Fe, Zn, Na and Cl. The synergistic and enhancing effects of co-inoculation of AM species on plant growth and the inhibiting effect of AM species on Na(+) rather than on Cl(-) uptake under salinity are also among the important findings of this research work.     

Historical and projected interactions between climate change and insect voltinism in a multivoltine species

Climate change can cause major changes to the dynamics of individual species and to those communities in which they interact. One effect of increasing temperatures is on insect voltinism, with the logical assumption that increases in surface temperatures would permit multivoltine species to increase the number of generations per year. Though insect development is primarily driven by temperature, most multivoltine insect species rely on photoperiodic cues, which do not change from year‐to‐year or in response to climate warming, to initiate diapause. Thus, the relationship between climate change and voltinism could be complex. We use a phenology model for grape berry moth, Paralobesia viteana (Clemens), which incorporates temperature‐dependent development and diapause termination, and photoperiod‐dependent diapause induction, to explore historical patterns in year‐to‐year voltinism fluctuations. We then extend this model to predict voltinism under varying scenarios of climate change to show the importance of both the quality and quantity of accumulated heat units. We also illustrate that increases in mean surface temperatures > 2 °C can have dramatic effects on insect voltinism by causing a shift in the ovipositional period that currently is subject to diapause‐inducing photoperiods.     

Auto-hydrolysis of lignocellulosics under extremely low sulphuric acid and high temperature conditions in batch reactor

Batch reactors were employed to investigate the kinetics of cellulose hydrolysis under extremely low acid (ELA) and high temperature condition. The sawdust was pretreated by Autohydrolysis prior to the batch reaction. The maximum yield of glucose obtained from the batch reactor experiment was about 70% for the pretreated sawdust, this occurred at 210 and 220°C. The maximum glucose yield from the untreated sawdust was much lower at these temperatures, about 55%. The maximum yields of glucose from the lignocellulosics were obtained between 15th and 20th minutes after which gradual decrease was observed.     

Understanding variability in greenhouse gas emission estimates of smallholder dairy farms in Indonesia

The International Journal of Life Cycle Assessment - Life cycle assessment studies on smallholder farms in tropical regions generally use data that is collected at one moment in time, which could...     

Comparison of greenhouse gas emission accounting for a constructed wetland wastewater treatment system

The method of systems accounting as a combination of process analysis and input–output analysis is applied to assess the greenhouse gas (GHG) emissions of Longdao River constructed wetland (LRCW), a typical constructed wetland in northern China. An improved GHG emission assessment for the constructed wetland wastewater treatment is made in this paper by using a local embodied GHG emissions intensity database for the Beijing economy 2002. Results show that the indirect GHG emission of the case constructed wetland accounts for 82.31% of the total GHG emissions. More than half of the indirect GHG emission is caused by the electricity. 64.48% of the total GHG emissions happened during the operation stage. There is a great gap between the GHG emissions of the LRCW in this study and in former study, which can be attributed to the diverse economy structures and technology levels of Beijing economy and Chinese economy.     

Vesicular-arbuscular mycorrhizae of epiphytic and terrestrial Piperaceae under field and greenhouse conditions

We examined the roots of 27 epiphytic and terrestrial species of Piperaceae collected in primary and secondary habitats in Monteverde, Costa Rica. Terrestrial roots of only two of the nine Peperomia species, two of eight Piper species, and of Pothomorphe umbellatum contained internal vesicles and/or arbuscules. We did not find internal vesicles and/or arbuscules in 3024 cm of fine roots of epiphytic Piperaceae, even though 15% of these root segments had associated external typical glomalean hyphae. Glomus and Acaulospora spores, and Gigaspora auxiliary cells occurred in both canopy and terrestrial habitats. After inoculation of a low nutrient substrate, the facultatively epiphytic Peperomia costaricensis averaged 23% mycorrhizal root length. Relatively high atmospheric inputs of dissolved inorganic nutrients that alleviate the requirement for mycorrhizae, and heterogeneity of mycorrhiza inocula in the canopy may explain the absence of mycorrhizae from epiphytic Piperaceae. We suggest that the Piperaceae comprises predominantly facultatively mycotrophic species, and that facultative mycotrophism facilitates their radiation to the canopy.     

Implications of dairy systems on enteric methane and postulated effects on total greenhouse gas emission

The effects of feeding total mixed ration (TMR) or pasture forage from a perennial sward under a management intensive grazing (MIG) regimen on grain intake and enteric methane (EM) emission were measured using chambers. Chamber measurement of EM was compared with that of SF₆ employed both within chamber and when cows grazed in the field. The impacts of the diet on farm gate greenhouse gas (GHG) emission were also postulated using the results of existing life cycle assessments. Emission of EM was measured in gas collection chambers in Spring and Fall. In Spring, pasture forage fiber quality was higher than that of the silage used in the TMR (47.5% v. 56.3% NDF; 24.3% v. 37.9% ADF). Higher forage quality from MIG subsequently resulted in 25% less grain use relative to TMR (0.24 v. 0.32 kg dry matter/kg milk) for MIG compared with TMR. The Fall forage fiber quality was still better, but the higher quality of MIG pasture was not as pronounced as that in Spring. Neither yield of fat-corrected milk (FCM) which averaged 28.3 kg/day, nor EM emission which averaged 18.9 g/kg dry matter intake (DMI) were significantly affected by diet in Spring. However, in the Fall, FCM from MIG (21.3 kg/day) was significantly lower than that from TMR (23.4 kg/day). Despite the differences in FCM yield, in terms of EM emission that averaged 21.9 g/kg DMI was not significantly different between the diets. In this study, grain requirement, but not EM, was a distinguishing feature of pasture and confinement systems. Considering the increased predicted GHG emissions arising from the production and use of grain needed to boost milk yield in confinement systems, EM intensity alone is a poor predictor of the potential impact of a dairy system on climate forcing.     

A global meta‐analysis of forest bioenergy greenhouse gas emission accounting studies

The potential greenhouse gas benefits of displacing fossil energy with biofuels are driving policy development in the absence of complete information. The potential carbon neutrality of forest biomass is a source of considerable scientific debate because of the complexity of dynamic forest ecosystems, varied feedstock types, and multiple energy production pathways. The lack of scientific consensus leaves decision makers struggling with contradicting technical advice. Analyzing previously published studies, our goal was to identify and prioritize those attributes of bioenergy greenhouse gas (GHG) emissions analysis that are most influential on length of carbon payback period. We investigated outcomes of 59 previously published forest biomass greenhouse gas emissions research studies published between 1991 and 2014. We identified attributes for each study and classified study cases by attributes. Using classification and regression tree analysis, we identified those attributes that are strong predictors of carbon payback period (e.g. the time required by the forest to recover through sequestration the carbon dioxide from biomass combusted for energy). The inclusion of wildfire dynamics proved to be the most influential in determining carbon payback period length compared to other factors such as feedstock type, baseline choice, and the incorporation of leakage calculations. Additionally, we demonstrate that evaluation criteria consistency is required to facilitate equitable comparison between projects. For carbon payback period calculations to provide operational insights to decision makers, future research should focus on creating common accounting principles for the most influential factors including temporal scale, natural disturbances, system boundaries, GHG emission metrics, and baselines.     

Volatile components of developing tomato fruit grown under field and greenhouse conditions

Volatile components of field- and glass greenhouse-grown tomatoes(Lycopersicon esculentum MILL., variety, V. R. Moscow) of differentmaturities were studied by gas-liquid and thin-layer chromatography.The following components were separated and identified: isobutylalcohol, isopentyl alcohol, hexyl alcohol, 2-methyl-3-hexanol,isovaleraldehyde, caproaldehyde, benzaldehyde, furfural, isopentylacetate, isopentyl butyrate, isopentyl isovalerate, butyl hexanoate,hexyl hexanoate, methyl salicylate and -pinene. Chromatogramswere consistent for both field- and greenhouse-grown tomatoesat all stages of maturity. Except for isovaleraldehyde and hexylalcohol, the biosynthesis of volatile components increased alongwith the growth of fruit. Isovaleraldehyde and hexyl alcohol,presumed to give the "green leafy" aroma of tomatoes, were foundto be in their highest concentrations at the breaker and thelarge-green stages, respectively. ¹This research was supported by a research grant—UI 00449—fromthe National Center for Urban and Industrial Health, U. S. PublicHealth Service.     

An exploration on greenhouse gas and ammonia production by insect species suitable for animal or human consumption

Background

Greenhouse gas (GHG) production, as a cause of climate change, is considered as one of the biggest problems society is currently facing. The livestock sector is one of the large contributors of anthropogenic GHG emissions. Also, large amounts of ammonia (NH₃), leading to soil nitrification and acidification, are produced by livestock. Therefore other sources of animal protein, like edible insects, are currently being considered.

Methodology/Principal Findings

An experiment was conducted to quantify production of carbon dioxide (CO₂) and average daily gain (ADG) as a measure of feed conversion efficiency, and to quantify the production of the greenhouse gases methane (CH₄) and nitrous oxide (N₂O) as well as NH₃ by five insect species of which the first three are considered edible: Tenebrio molitor, Acheta domesticus, Locusta migratoria, Pachnoda marginata, and Blaptica dubia. Large differences were found among the species regarding their production of CO₂ and GHGs. The insects in this study had a higher relative growth rate and emitted comparable or lower amounts of GHG than described in literature for pigs and much lower amounts of GHG than cattle. The same was true for CO₂ production per kg of metabolic weight and per kg of mass gain. Furthermore, also the production of NH₃ by insects was lower than for conventional livestock.

Conclusions/Significance

This study therefore indicates that insects could serve as a more environmentally friendly alternative for the production of animal protein with respect to GHG and NH₃ emissions. The results of this study can be used as basic information to compare the production of insects with conventional livestock by means of a life cycle analysis.     

The respiratory system of Chromobacterium violaceum grown under conditions of high and low cyanide evolution.

The particulate fraction of disrupted Chromobacterium violaceum grown under cyanide-evolving conditions was unable to oxidize ascorbate plus N,N,N',N'-tetra-methyl-p-phenylenediamine (TMPD), but oxidized NADH and succinate by a linear respiratory pathway which was very resistant to inhibition by cyanide. When the bacteria were grown under conditions where little cyanide evolution occurred, particulate fractions developed the ability to oxidize ascorbate-TMPD by a pathway highly sensitive to cyanide inhibition; respiratory activity with NADH and succinate proceeded via both the cyanide-sensitive and-resistant pathways. Studies with respiratory inhibitors, and the cytochrome compositions of the fractions derived from cultures grown under both conditions, are presented. A soluble, carbon monoxide-binding cytochrome c was found, and this appears similar to those found recently in Beneckea natiegens, methylotrophic bacteria and the marine pseudomonad B16.     

土地利用方式和培养温度对土壤氮转化及温室气体排放的影响

在好氧条件下研究土地利用方式(林地、草地)及培养温度(10、15 ℃)对加拿大和中国土壤的硝化作用、氮矿化作用以及N2O和CO2排放的影响.结果表明:草地土壤中的硝化作用和N2O排放量大于林地土壤,中国草地土硝化作用最强.10和15℃下中国草地土硝化速率分别为2.10和2.86 mg N·kg-1·d-1,15 d的N2O累积排放量分别为10.2和15.4μg N2O-N·kg-1.pH是影响土壤硝化作用强度和N2O排放的主要因素,与两者均呈显著正相关.林地土壤的矿化作用和CO2排放量高于草地,中国林地土壤的矿化作用最强,其平均矿化速率在10和15℃时分别为3.08和2.87mgN·kg-1 ·d-1.加拿大林地土壤CO2排放量最高,其15 d的累积排放量在10和15℃时分别为314和370 mg CO2-C·kg-1,土壤有机碳和水溶性有机碳含量分别与有机氮矿化作用和CO2排放量呈显著正相关.温度增加促进草地土壤硝化作用及林地和草地土壤中N2O的排放,也显著促进林地土壤中CO2的排放.