Biogenic methane production in formation waters from a large gas field in the North Sea

Methanogenesis was investigated in formation waters from a North Sea oil rimmed gas accumulation containing biodegraded oil, which has not been subject to seawater injection. Activity and growth of hydrogenotrophic methanogens was measured but acetoclastic methanogenesis was not detected. Hydrogenotrophic methanogens showed activity between 40 and 80°C with a temperature optimum (ca. 70°C) consistent with in situ reservoir temperatures. They were also active over a broad salinity range, up to and consistent with the high salinity of the waters (90 g l⁻¹). These findings suggest the methanogens are indigenous to the reservoir. The conversion of H₂ and CO₂ to CH₄ in methanogenic enrichments was enhanced by the addition of inorganic nutrients and was correlated with cell growth. Addition of yeast extract also stimulated methanogenesis. Archaeal 16S rRNA gene sequences recovered from enrichment cultures were closely related to Methanothermobacter spp. which have been identified in other high-temperature petroleum reservoirs. It has recently been suggested that methanogenic oil degradation may be a major factor in the development of the world’s heavy oils and represent a significant and ongoing process in conventional deposits. Although an oil-degrading methanogenic consortium was not enriched from these samples the presence and activity of communities of fermentative bacteria and methanogenic archaea was demonstrated. Stimulation of methanogenesis by addition of nutrients suggests that in situ methanogenic biodegradation of oil could be harnessed to enhance recovery of stranded energy assets from such petroleum systems.     

The Energy Structure of the Canadian Economy

We developed a model of a national economy in which the phenomena of supply, demand, economic growth, and international trade are represented in terms of energy flows. In examining the structure of the economy, we distinguish between the energy embodied in capital assets used in the production and distribution of energy and that embodied in capital assets and goods that consume energy. Sources used to quantify the energy flows include: end‐use energy data by economic sector; International Energy Agency–style national energy balances, and national input‐output tables. As an example, the Canadian economy for 2008 produced 16.97 exajoules (EJ) of energy, which after net export of 6.16 EJ and other adjustments left a total primary energy consumption of 10.61 EJ. The energy supply and distribution sectors used close to 32% (3.36 EJ) of total primary consumption. Analysis of primary energy consumption shows that 25.14% was embodied in household consumption, 22.85% was consumed directly by households, 7.88% was embodied in government services, and 34.07% was embodied in exports. Of significance to economic growth, 7.14% was embodied in capital in energy demanding sectors, 1.25% in energy consuming personal assets, and 1.52% in supply sector capital. The energy return on energy investment was relatively constant, averaging 5.14 between 1990 and 2008. Capital investments required to decouple the Canadian economy from its dependence on fossil fuels are discerned.     

Establishing temperate crustose early Holocene coralline algae as archives for palaeoenvironmental reconstructions of the shallow water habitats of the Mediterranean Sea

Over the past decades, coralline algae have increasingly been used as archives of palaeoclimate information due to their seasonal growth bands and their vast distribution from high latitudes to the tropics. Traditionally, these reconstructions have been performed mainly on high latitude species, limiting the geographical area of their potential use. Here we assess the use of temperate crustose fossil coralline algae from shallow water habitats for palaeoenvironmental reconstruction to generate records of past climate change. We determine the potential of three different species of coralline algae, Lithothamnion minervae, Lithophyllum stictaeforme and Mesophyllum philippii, with different growth patterns, as archives for pH (δ¹¹B) and temperature (Mg/Ca) reconstruction in the Mediterranean Sea. Mg concentration is driven by temperature but modulated by growth rate, which is controlled by species-specific and intraspecific growth patterns. L. minervae is a good temperature recorder, showing a moderate warming trend in specimens from 11.37 cal ka BP (from 14.2 ± 0.4°C to 14.9 ± 0.15°C) to today. In contrast to Mg, all genera showed consistent values of boron isotopes (δ¹¹B) suggesting a common control on boron incorporation. The recorded δ¹¹B in modern and fossil coralline specimens is in agreement with literature data about early Holocene pH, opening new perspectives of coralline-based, high-resolution pH reconstructions in deep time.     

The effect of low energy electric shock on cortisol, β-endorphin, heart rate and behaviour of cattle

Electrical stimuli are used increasingly to confine cattle, whether through conventional electric fencing or the development of ‘virtual’ fencing systems. Two experiments were conducted to assess behavioural, heart rate and stress hormone responses of cattle to electrical stimuli typically used in such confinement applications. In the first experiment, 30 steers (18-months old; n = 10 per treatment) were held in a handling crush for 15 min after receiving one of the following treatments: nothing (control); delivery of three shocks at 2 s intervals (600 V, 250 mW); and restraint in a head bail for 3 min. Plasma cortisol and β-endorphin concentrations were measured at 0, 5, 10, 15 min, 1, 2, 3, and 4 h. In a second experiment, heart rate and behaviour were measured in 17 heifers (18 months of age) subjected to one of the following treatments whilst held in a crush for 10 min: nothing (control; n = 5); delivery of three shocks at 2 s intervals (600 V, 250 mW; n = 6); and restraint in a head bail for 3 min (n = 6). Cortisol and β-endorphin concentrations did not differ between treatments (P > 0.05). Whilst animals were receiving the treatments, heart rate was lower when head restrained compared with shock or control treatments (P = 0.009) and did not differ between control and electric shock treatments (P = 0.35). Upon release from the crush, heart rate was higher in shock and head restrained treatments than the control treatment (P = 0.005). Animals receiving the electric shock treatment tossed their heads more frequently whilst in the crush than control animals (P = 0.012) but did not differ from the other treatments in the number of vocalisations, tail swishes, steps back and forward, head tilts and head turns. There was a significant effect of treatment on flight time (P = 0.005); animals receiving the electric shocks were faster to leave the crush than control animals (P = 0.005) and there was no difference between head restraint and shock treatment (P = 0.86). In 10 min following release from the crush, there was no treatment difference in the time to start feeding. This study suggests that the stress response of cattle to low energy electric shocks is minimal and is similar to that induced by restraint in a crush.     

Chemical Composition and Biological Studies of the Essential Oil from Aerial Parts of Beta vulgaris subsp. maritima (L.) Arcang. Growing in Tunisia

The chemical composition, antioxidant, cytotoxic, anticholinesterase and anti‐tyrosinase activities of the hydrodistilled essential oil of the aerial parts of Beta vulgaris subsp. maritime (L.) Arcang . from Tunisia have been evaluated. The chemical composition of the oil (yield 0.037% [w/w]), determined by GC‐FID and GC/MS is reported for the first time. Twenty five components, accounting for 98.1% of the total oil have been identified. The oil was characterized by a high proportion of oxygenated sesquiterpenes (39.2%), followed by sesquiterpene hydrocarbons (30.3%) and one apocarotenoids (26.3%). The main compounds were γ‐irone (26.3%), α‐cadinol (12.1%), T‐cadinol (10.6%), bicyclogermacrene (10.4%) and δ‐cadinene (6.0%). The isolated oil was tested for its antioxidant activity using the DPPH^·, ABTS^+·, catalase, and paraoxonase assays and also for its cytotoxic, anticholinesterase, and anti‐tyrosinase activities. The essential oil exhibited high antioxidant activity (IC₅₀ = 0.055 ± 0.006 mg/ml) and important result oncatalase (524.447 ± 2.58 Units/mg protein). Furthermore, it exerted a significant cytotoxic effect against A549 cell line, with IC₅₀ = 42.44 ± 1.40 μg/ml. The results indicate that the essential oil of B. vulgaris subsp. maritima (L.) Arcang . aerial parts may be used in future as an alternative to synthetic antioxidant agents, with potential application in the food and pharmaceutical industries.     

Aflatoxins levels in vegetable oils in Khartoum State,Sudan

Vegetable oil (n = 81) for human consumption from Khartoum State in Sudan were analyzed for aflatoxins (AFs), using high-performance liquid chromatography (HPLC) with fluorescence detection following extraction with methanol:water (80:20) and clean-up using petroleum ether. Sampling included sesame oil (n = 14), peanut oil (n = 21), and sunflower oil (n = 19) purchased from retail shops, and mixed oil produced by two local manufacturers (factory A, n = 15; factory B, n = 12). AF contamination was found in 80/81 (98.8%) samples, with total AF levels ( AFB₁ + AFB₂ + AFG₁ + AFG₂ ) \left( {{\hbox{AF}}{{\hbox{B}}_{\rm{1}}} + {\hbox{AF}}{{\hbox{B}}_{\rm{2}}} + {\hbox{AF}}{{\hbox{G}}_{\rm{1}}} + {\hbox{AF}}{{\hbox{G}}_{\rm{2}}}} \right) of 0.43–339.9 μg/kg and mean level of 57.5 μg/kg. All sesame oils had total AF levels that were much higher than the United States Food and Drug Administration acceptable limit of 20 μg/kg. The percentage of samples with total AF values <20 μg/kg in other oils varied and was 57.14% in peanut oil, 36.8% in sunflower oil, 66.7% (mixed oil from factory A), and 91.7% (mixed oil from factory B). In conclusion, the levels of total AFs in edible oil as available in Khartoum State are quite alarming. To reduce the health hazards for the consumers, an intervention strategy to manage AFs in food commodities from Sudan is urgently required.     

Biorefinery for combined production of jet fuel and ethanol from lipid‐producing sugarcane: a techno‐economic evaluation

Replacing fossil fuels with an economically viable green alternative at scale has proved most challenging in the aviation sector. Recently sugarcane, the most productive crop on the planet, has been engineered to accumulate lipids. This opens the way for production of far more industrial vegetable oil per acre than previously possible. This study performs techno‐economic feasibility analysis of jet fuel production from this new cost efficient and high yield feedstock. A comprehensive process model for biorefinery producing hydrotreated jet fuel (from lipids) and ethanol (from sugars), with 1 600 000 MT yr^?1 lipid‐cane processing capacity, was developed in SuperPro Designer. Considering lipid‐cane development is continuing for higher oil concentrations, analysis was performed with lipid‐cane containing 5%, 10%, 15%, and 20% lipids. Capital investments for the biorefinery ranged from 238.1 to 351.2 million USD, with jet fuel capacities of 12.6–50.5 million liters (correspondingly ethanol production of nil to 102.6 million liters). The production cost of jet fuel for different scenarios was estimated Replacing fossil fuels with an economically viable green alternative at scale has proved most challenging in the aviation sector. Recently sugarcane, the most productive crop on the planet, has been engineered to accumulate lipids. This opens the way for production of far more industrial vegetable oil per acre than previously possible. This study performs techno‐economic feasibility analysis of jet fuel production from this new cost efficient and high yield feedstock. A comprehensive process model for biorefinery producing hydrotreated jet fuel (from lipids) and ethanol (from sugars), with 1 600 000 MT yr^?1 lipid‐cane processing capacity, was developed in SuperPro Designer. Considering lipid‐cane development is continuing for higher oil concentrations, analysis was performed with lipid‐cane containing 5%, 10%, 15%, and 20% lipids. Capital investments for the biorefinery ranged from 238.1 to 351.2 million USD, with jet fuel capacities of 12.6–50.5 million liters (correspondingly ethanol production of nil to 102.6 million liters). The production cost of jet fuel for different scenarios was estimated $0.73 to $1.79 per liter ($2.74 to $6.76 per gal) of jet fuel. In all cases, the cost of raw materials accounted for more than 70% of total operational cost. Biorefinery was observed self‐sustainable for steam and electricity requirement, because of in‐house steam and electricity generation from burning of bagasse. Minimum fuel selling prices with a 10% discount rate for 20% lipid case was estimated $1.40/L ($5.31/gal), which was lower than most of the reported prices of renewable jet fuel produced from other oil crops and algae. Along with lower production costs, lipid‐cane could produce as high as 16 times the jet fuel (6307 L ha^?1) per unit land than that of other oil crops and do so using low‐value land unsuited to most other crops, while being highly water and nitrogen use efficient.     

Coccolith volume of the Southern Ocean coccolithophore Emiliania huxleyi as a possible indicator for palaeo‐cell volume

Coccolithophores are a key functional phytoplankton group and produce minute calcite plates (coccoliths) in the sunlit layer of the pelagic ocean. Coccoliths significantly contribute to the sediment record since the Triassic and their geometry have been subject to palaeoceanographic and biological studies to retrieve information on past environmental conditions. Here, we present a comprehensive analysis of coccolith, coccosphere and cell volume data of the Southern Ocean Emiliania huxleyi ecotype A, subject to gradients of temperature, irradiance, carbonate chemistry and macronutrient limitation. All tested environmental drivers significantly affect coccosphere, coccolith and cell volume with driver‐specific sensitivities. However, a highly significant correlation emerged between cell and coccolith volume with V_coccolith = 0.012 ± 0.001 * V_cell + 0.234 ± 0.066 (n = 23, r² = .85, p < .0001, σ_est = 0.127), indicating a primary control of coccolith volume by physiological modulated changes in cell volume. We discuss the possible application of fossil coccolith volume as an indicator for cell volume/size and growth rate and, additionally, illustrate that macronutrient limitation of phosphorus and nitrogen has the predominant influence on coccolith volume in respect to other environmental drivers. Our results provide a solid basis for the application of coccolith volume and geometry as a palaeo‐proxy and shed light on the underlying physiological reasons, offering a valuable tool to investigate the fossil record of the coccolithophore E. huxleyi.     

Environmental impacts and limitations of third‐generation biobutanol: Life cycle assessment of n‐butanol produced by genetically engineered cyanobacteria

Photosynthetic cyanobacteria have attracted interest as production organisms for third‐generation biofuels, where sunlight and CO₂ are used by microbes directly to synthesize fuel molecules. A particularly suitable biofuel is n‐butanol, and there have been several laboratory reports of genetically engineered photosynthetic cyanobacteria capable of synthesizing and secreting n‐butanol. This work evaluates the environmental impacts and cumulative energy demand (CED) of cyanobacteria‐produced n‐butanol through a cradle‐to‐grave consequential life cycle assessment (LCA). A hypothetical production plant in northern Sweden (area 1 ha, producing 5–85 m³ n‐butanol per year) was considered, and a range of cultivation formats and cellular productivity scenarios assessed. Depending on the scenario, greenhouse gas emissions (GHGe) ranged from 16.9 to 58.6 gCO₂eq/MJ_BuOH and the CED from 3.8 to 13 MJ/MJ_BuOH. Only with the assumption of a nearby paper mill to supply waste sources for heat and CO₂ was the sustainability requirement of at least 60% GHGe savings compared to fossil fuels reached, though placement in northern Sweden reduced energy needed for reactor cooling. A high CED in all scenarios shows that significant metabolic engineering is necessary, such as a carbon partitioning of >90% to n‐butanol, as well as improved light utilization, to begin to displace fossil fuels or even first‐ and second‐generation bioethanol.     

Isotopic niche differs between seal and fish‐eating killer whales (Orcinus orca) in northern Norway

Ecological diversity has been reported for killer whales (Orcinus orca) throughout the North Atlantic but patterns of prey specialization have remained poorly understood. We quantify interindividual dietary variations in killer whales (n = 38) sampled throughout the year in 2017–2018 in northern Norway using stable isotopic nitrogen (δ¹⁵N: ¹⁵N/¹⁴N) and carbon (δ¹³C: ¹³C/¹²C) ratios. A Gaussian mixture model assigned sampled individuals to three differentiated clusters, characterized by disparate nonoverlapping isotopic niches, that were consistent with predatory field observations: seal‐eaters, herring‐eaters, and lumpfish‐eaters. Seal‐eaters showed higher δ¹⁵N values (mean ± SD: 12.6 ± 0.3‰, range = 12.3–13.2‰, n = 10) compared to herring‐eaters (mean ± SD: 11.7 ± 0.2‰, range = 11.4–11.9‰, n = 19) and lumpfish‐eaters (mean ± SD: 11.6 ± 0.2‰, range = 11.3–11.9, n = 9). Elevated δ¹⁵N values for seal‐eaters, regardless of sampling season, confirmed feeding at high trophic levels throughout the year. However, a wide isotopic niche and low measured δ¹⁵N values in the seal‐eaters, compared to that of whales that would eat solely seals (δ_N‐measured = 12.6 vs. δ_N‐expected = 15.5), indicated a diverse diet that includes both fish and mammal prey. A narrow niche for killer whales sampled at herring and lumpfish seasonal grounds supported seasonal prey specialization reflective of local peaks in prey abundance for the two fish‐eating groups. Our results, thus, show differences in prey specialization within this killer whale population in Norway and that the episodic observations of killer whales feeding on prey other than fish are a consistent behavior, as reflected in different isotopic niches between seal and fish‐eating individuals.     

Composition and Chemical Variability of Ivoirian Polyalthia oliveri Leaf Oil

The chemical composition of 45 essential oil samples isolated from the leaves of Polyalthia oliveri harvested in three Ivoirian forests was investigated by GC‐FID (retention indices measured on two columns of different polarities), and by ¹³C‐NMR, following a method developed in our laboratory. In total, 41 components were identified. The content of the main components varied drastically from sample to sample: (E)‐β‐caryophyllene (1.2 – 50.8%), α‐humulene (0.6 – 47.7%), isoguaiene (0 – 27.9%), alloaromadendrene (0 – 24.7%), germacrene B (0 – 18.3%), δ‐cadinene (0.4 – 19.3%), and β‐selinene (0.2 – 18.5%). The analysis of six oil samples selected in function of their chromatographic profiles is reported in detail. The 45 oil compositions were submitted to hierarchical cluster and principal components analysis, which allowed the distinction of three groups within the oil samples. The compositions of the oils from group I (15 samples) and II (12 samples) were dominated by (E)‐β‐caryophyllene and α‐humulene, respectively. Oil samples of group III (18 samples) needed to be partitioned into four subgroups III.1–III.4 whose compositions were dominated by alloaromadenrene, isoguaiene, germacrene B, and δ‐cadinene, respectively.     

Trophic discrimination factor of nitrogen isotopes within amino acids in the dobsonfly Protohermes grandis (Megaloptera: Corydalidae) larvae in a controlled feeding experiment

The trophic discrimination factor (TDF) of nitrogen isotopes (¹⁵N/¹⁴N) within amino acids, between a stream‐dwelling dobsonfly larva (Protohermes grandis: Megaloptera; Corydalidae) and its diet (chironomid larvae), was determined in controlled feeding experiments. Last‐instar larvae of P. grandis were collected from the Yozawa‐gawa River, central Japan, and reared in the laboratory. After fed to satiation for 1 month, one group of larvae was each fed one living chironomid larva per day for 4 weeks, while a second group was starved for 8 weeks. The larvae were harvested at intervals and the nitrogen isotopic composition of glutamic acid (δ¹⁵N_Glu) and phenylalanine (δ¹⁵N_Phe) were determined to calculate TDF. The mean TDF of satiated and starved larvae were 7.1‰ ± 0.5‰ (n = 3) and 7.3‰ ± 0.5‰ (n = 5), respectively. Thus, the TDF for P. grandis larvae in this study was similar to that reported for other arthropods (approximately 7‰) and was independent of satiation or starvation. A previous study of wild P. grandis larvae, based on the δ¹⁵N_Glu and δ¹⁵N_Phe values, estimated its trophic position (TP) as approximately 2.0 ± 0.1 (n = 5), a low value close to that of algivores, although they are generally characterized as carnivores (usually accepted as TP ≥ 3). The TDF for P. grandis larvae suggests that their low TPs in nature were caused by incorporation of vascular plant‐derived amino acids (with a different δ¹⁵N profile from that of algae) and not by an unusually low TDF or by the effects of the satiation/starvation on amino acid metabolism.     

Insecticidal Activity of the Leaf Essential Oil of Peperomia borbonensis Miq. (Piperaceae) and Its Major Components against the Melon Fly Bactrocera cucurbitae (Diptera: Tephritidae)

The essential oil from the leaves of Peperomia borbonensis from Réunion Island was obtained by hydrodistillation and characterized using GC‐FID, GC/MS and NMR. The main components were myristicin (39.5%) and elemicin (26.6%). The essential oil (EO) of Peperomia borbonensis and its major compounds (myristicin and elemicin), pure or in a mixture, were evaluated for their insecticidal activity against Bactrocera cucurbitae (Diptera: Tephritidae) using a filter paper impregnated bioassay. The concentrations necessary to kill 50% (LC₅₀) and 90% (LC₉₀) of the flies in three hours were determined. The LC₅₀ value was 0.23 ± 0.009 mg/cm² and the LC₉₀ value was 0.34 ± 0.015 mg/cm² for the EO. The median lethal time (LT₅₀) was determined to compare the toxicity of EO and the major constituents. The EO was the most potent insecticide (LT₅₀ = 98 ± 2 min), followed by the mixture of myristicin and elemicin (1.4:1) (LT₅₀ = 127 ± 2 min) indicating that the efficiency of the EO is potentiated by minor compounds and emphasizing one of the major assets of EOs against pure molecules.     

Phylogeny,ecology and deep time: 2D outline analysis of anuran skulls from the Early Cretaceous to the Recent

Anurans have a long fossil record, spanning from the Early Jurassic to the Recent. However, specimens are often severely flattened, limiting their inclusion in quantitative analyses of morphological evolution. We perform a two‐dimensional morphometric analysis of anuran skull outlines, incorporating 42 Early Cretaceous to Miocene species, as well as 93 extant species in 32 families. Outlines were traced in tpsDig2 and analysed with elliptical Fourier analysis. Fourier coefficients were used in MANOVAs, phylogenetic MANOVAs (as significant phylogenetic signal was found) and disparity analyses across multiple ecological and life history groupings. The Neotropical realm showed higher disparity than the Australian, Palaearctic and Oriental realms (p = 0.007, 0.013, 0.038, respectively) suggesting concordance of disparity and diversity. Developmental strategy had a weak effect on skull shape (R² = 0.02, p = 0.039) and disparity was similar in metamorphosing and direct developing frogs. Ecological niche was a significant discriminator of skull shape (F = 1.43, p = 0.004) but not after phylogenetic correction. Evolutionary allometry had a small but significant influence on the cranial outlines of the combined extant and fossil dataset (R² = 0.05, p = 0.004). Finally, morphospace occupation appears to have changed over time (F = 1.59, p = 5 × 10^?10). However, as with ecological signal, this shift appears to be largely driven by phylogeny and was not significant after phylogenetic correction (R² = 0.26, p = 0.22). This study thus suggests that frog skull evolution is shaped more by phylogenetic constraints than by ecology.     

Biological activity of some plant essential oils against <Emphasis Type="Italic">Varroa destructor</Emphasis> (Acari: Varroidae), an ectoparasitic mite of <Emphasis Type="Italic">Apis mellifera</Emphasis> (Hymenoptera: Apidae)

This experiment was conducted to evaluate acaricidal activity of the essential oils of Thymus kotschyanus, Ferula assa-foetida and Eucalyptus camaldulensis against Varroa destructor under laboratory conditions. Moreover, fumigant toxicity of these oils was tested on Apis mellifera. After preliminary dose-setting experiments, mites and honey bees were exposed to different concentrations of the oil, with 10 h exposure time. Essential oil of T. kotschyanus appeared the most potent fumigant for V. destructor (LC₅₀ = 1.07, 95% confidence limit (CL) = 0.87–1.26 μl/l air), followed by E. camaldulensis (LC₅₀ = 1.74, 95% CL = 0.96–2.50 μl/l air). The lowest acaricidal activity (LC₅₀ = 2.46, 95% CL = 2.10–2.86 μl/l air) was attributed to essential oil of F. assa-foetida. Surprisingly, among the three oils tested, essential oil of T. kotschyanus had the lowest insecticidal activity against A. mellifera (LC₅₀ = 5.08, 95% CL = 4.54–5.06 μl/l air). These findings proved that essential oil of T. kotschyanus has potential of practical value for use as alternative acaricide in the management of varroa in apiaries.     

Characterization of 2T engine oil degrading indigenous bacteria,isolated from high altitude (Mussoorie), India

The biodegradability of petroleum hydrocarbons such as polycyclic aromatic hydrocarbons (PAHs) and n-branched alkanes etc. of 2T engine oil were studied in aqueous media using bacterial strain isolated from petroleum contaminated soil of high altitude. Out of five petroleum degrading bacterial strain one of the most growing bacteria was identified as Enterobacter strain by morphological, physiological, biochemical and partial sequencing of 16S rDNA. This strain was capable of degrading 75 ± 3% of n-alkanes, 32 ± 5% PAHs, and the abiotic loss was 24 ± 6% during 10 days incubation period. 85 ± 2% of n-alkanes and 51 ± 3% PAHs were biodegraded in 20 days. The abiotic loss during this period was 15 ± 3%. In 30 days of incubation period 98% ± 1% n-alkanes and 75 ± 3% PAHs were degraded. As expected abiotic losses were smaller with increasing long chain alkanes and PAH’s concentration. An increment in oil degradation was correlated to an increase in cell number indicating that the bacterial isolate was responsible for the oil degradation. The hydrocarbon contents were measured by Shimadzu QP-2000 Gas chromatography/mass spectrometry by ULBON HR-1 column.     

Chemical Variability of Ivoirian Xylopia rubescens Leaf Oil

Forty‐two essential oil samples were isolated from leaves of Xylopia rubescens harvested in three forests of Southern Ivory Coast. All the samples have been submitted to GC‐FID and the retention indices (RIs) of individual components have been measured on two capillary columns of different polarity. In addition, 20 oil samples, selected on the basis of their chromatographic profile, were also analyzed by ¹³C‐NMR and 24 components (78.0 – 92.4% of the whole compositions) have been identified. The content of the main components varied drastically from sample to sample: furanoguaia‐1,4‐diene (5.7 – 54.1%), furanoguaia‐1,3‐diene (1.1 – 10.5%), (8Z,11Z,14Z)‐heptadeca‐8,11,14‐trien‐2‐one (4.3 – 16.0%), and (E)‐β‐caryophyllene (1.7 – 17.3%). Hierarchical cluster and principal components analysis of the 42 oil compositions allowed the distinction of two well‐differentiated groups of unequal importance within the oil samples. Oil samples of the main group (Group II) contained mainly furanoguaia‐1,4‐diene (mean [M] = 43.1%; standard deviation [SD] = 3.2%) while furanoguaia‐1,3‐diene (M = 8.4%; SD = 0.9%) and (8Z,11Z,14Z)‐heptadeca‐8,11,14‐trien‐2‐one (M = 7.1%; SD = 1.5%) were present at appreciable contents. The composition of Group I was dominated by furanoguaia‐1,4‐diene (M = 17.0%; SD = 8.5%), (8Z,11Z,14Z)‐heptadeca‐8,11,14‐trien‐2‐one (M = 10.2%; SD = 2.4%) and (E)‐β‐caryophyllene (M = 9.5%; SD = 5.3%).     

Method for endogenizing capital in the United States Environmentally‐Extended Input‐Output model

Each year businesses, governments, and homeowners in the United States invest around one fifth of gross domestic product into the creation of capital assets such as buildings, machinery, and software to enable production and consumption. Use of capital is typically included to some extent in environmental life cycle assessments of goods and services but is not incorporated into most environmentally extended input‐output (EEIO) models, including the US Environmental Protection Agency's USEEIO. Capital assets are typically created in years prior to their use, so a challenge lies in distributing the impacts of their creation over time. In this work, a highly detailed capital flow matrix approach is followed to distribute the use of fixed capital assets to consuming industries. Data from the US Bureau of Economic Analysis's Fixed Asset Accounts is merged with its Industry Accounts data by the creation of concordance tables. Public highways and streets are partially reallocated to industries operating vehicles. The resulting capital use matrix is later combined into a modified USEEIO. “Housing” is found to be the largest consumer of fixed assets, followed by general government, fossil fuel extraction, and financial industries involved in leasing. Construction, vehicles, and machinery are mostly used by industries in the form of fixed assets. The types of fixed assets used by industries are consistent with expectations: housing is dominated by structures, transport by equipment, and information industries by intellectual property products.     

Range and uncertainties in estimating delays in greenhouse gas mitigation potential of forest bioenergy sourced from Canadian forests

Accurately assessing the delay before the substitution of fossil fuel by forest bioenergy starts having a net beneficial impact on atmospheric CO₂ is becoming important as the cost of delaying GHG emission reductions is increasingly being recognized. We documented the time to carbon (C) parity of forest bioenergy sourced from different feedstocks (harvest residues, salvaged trees, and green trees), typical of forest biomass production in Canada, used to replace three fossil fuel types (coal, oil, and natural gas) in heating or power generation. The time to C parity is defined as the time needed for the newly established bioenergy system to reach the cumulative C emissions of a fossil fuel, counterfactual system. Furthermore, we estimated an uncertainty period derived from the difference in C parity time between predefined best‐ and worst‐case scenarios, in which parameter values related to the supply chain and forest dynamics varied. The results indicate short‐to‐long ranking of C parity times for residues < salvaged trees < green trees and for substituting the less energy‐dense fossil fuels (coal < oil < natural gas). A sensitivity analysis indicated that silviculture and enhanced conversion efficiency, when occurring only in the bioenergy system, help reduce time to C parity. The uncertainty around the estimate of C parity time is generally small and inconsequential in the case of harvest residues but is generally large for the other feedstocks, indicating that meeting specific C parity time using feedstock other than residues is possible, but would require very specific conditions. Overall, the use of single parity time values to evaluate the performance of a particular feedstock in mitigating GHG emissions should be questioned given the importance of uncertainty as an inherent component of any bioenergy project.     

Composition and Chemical Variability of the Needle Oil from Pinus halepensis growing in Corsica

The composition of oil samples isolated from needles of Pinus halepensis growing in three locations in Corsica (Saleccia, Capo di Feno, and Tre Padule) has been investigated by combination of chromatographic (GC with retention indices) and spectroscopic (MS and ¹³C‐NMR) techniques. In total, 35 compounds that accounted for 77 – 100% of the whole composition have been identified. α‐Pinene, myrcene, and (E)‐β‐caryophyllene were the major component followed by α‐humulene and 2‐phenylethyl isovalerate. Various diterpenes have been identified as minor components. 47 Oil samples isolated from pine needles have been analyzed and were differentiated in two groups. Oil samples of the first group (15 samples) contained myrcene (M = 28.1 g/100 g; SD = 10.6) and (E)‐β‐caryophyllene (M = 19.0 g/100 g; SD = 2.2) as major components and diterpenes were absent. All these oil samples were isolated from pine needles harvested in Saleccia. Oil samples of the second group (32 samples) contained mostly (E)‐β‐caryophyllene (M = 28.7 g/100 g; SD = 7.9), α‐pinene (M = 12.3 g/100 g; SD = 3.6), and myrcene (M = 11.7 g/100 g; SD = 7.3). All these oil samples were isolated from pine needles harvested in Capo di Feno and Tre Padule.