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Atmospheric chemical composition affects foliar chemical composition, which in turn influences the dynamics of both herbivory and decomposition in ecosystems. We assessed the independent and interactive effects of CO2 and O3 fumigation on foliar chemistry of quaking aspen (Populus tremuloides) and paper birch (Betula papyrifera) at a Free-Air CO2 Enrichment (FACE) facility in northern Wisconsin. Leaf samples were collected at five time periods during a single growing season, and analyzed for nitrogen, starch and condensed tannin concentrations, nitrogen resorption efficiencies (NREs), and C:N ratios. Enriched CO2 reduced foliar nitrogen concentrations in aspen and birch; O3 only marginally reduced nitrogen concentrations. NREs were unaffected by pollution treatment in aspen, declined with O3 exposure in birch, and thisdecline was ameliorated by enriched CO2. C:N ratios of abscised leaves increased in response to enriched CO2 in both tree species. O3 did not significantly alter C:N ratios in aspen, although values tended to be higher in +CO2+O3 leaves. For birch, O3 decreased C:N ratios underambient CO2 and increased C:N ratios under elevated CO2. Thus, under the combined pollutants, the C:N ratios of both aspen and birch leaves were elevated above the averaged responses to the individual and independent trace gas treatments. Starch concentrations were largely unresponsive to CO2 and O3treatments in aspen, but increased in response to elevated CO2 in birch. Levels of condensed tannins were negligibly affected by CO2 and O3 treatments in aspen, but increased in response to enriched CO2 in birch. Results from this work suggest that changes in foliar chemical composition elicited by enriched CO2 are likely to impact herbivory and decomposition [ABSTRACT FROM AUTHOR]

Highlights: [•] Two Kraft lignins were precipitated from black liquors supplied by pulp and paper industry, using carbon dioxide. [•] Structure and composition of lignins were determined to vary according to the plant origin and the extraction process. [•] Kraft lignins are evaluated as the best samples for application in biocomposites based on polyethylene. [•] Pyrolytic and Soda lignins are better adapted for resin and adhesives application or as additives in polyolefins (antioxidant, UV stabilizer or fire-retardant). [ABSTRACT FROM AUTHOR]

• Nanogel particles for CO 2 capture with lower cycles (303–348 K) are developed. • Carbon paper as supporter shows higher CO 2 capacity, adsorption and desorption rate. • Avrami's fractional order model accurately predicts the CO 2 uptake behaviors. • The CO 2 capture process is governed by film and intraparticle diffusion resistance. • Carbon paper as supporter shows lower sensible heat and desorption activation energy. Amine-containing nanogel particles with a lower cooling and heating cycles (303–348 K), which is beneficial to limit the degradation and volatile of amine, has been developed as promising absorbents for CO 2 capture. It is extremely important to understand the CO 2 capture kinetics and mechanisms for design and operation of corresponding processes. In present work, poly tetra fluoroethylene and carbon paper were used to support the GPs by filtering and loading method. The CO 2 uptake and release performance of poly tetra fluoroethylene and carbon paper supported nanogel particles was measured. It was found that carbon paper as supporter shows higher CO 2 capacity and desorption rate. A comparison of three different kinetic models shows that carbon paper as supporter gives a more enhanced kinetic behavior. Avrami's fractional order model presents the best fit to experimental data. To further investigate the mechanism of CO 2 uptake on absorbents, interparticle diffusion model, intraparticle diffusion model and Boyd's film diffusion model were also applied. Film diffusion resistance governed the mass transfer rate of CO 2 uptake on studied absorbents at the initial CO 2 uptake stages. In the following stages, intra-particle diffusion resistance plays a major role until the equilibrium is reached. The sensible heat of carbon paper as supporter is about 25% lower than that of poly tetra fluoroethylene as supporter. The desorption activation energy obtained from the Arrhenius equation is 18 kJ/mol for carbon paper as supporter, which is 84% lower than that of the typical aqueous MEA solvent. [ABSTRACT FROM AUTHOR]

Abstract: This manuscript stresses the need of experimental measurements and mathematical models of sorption isotherms/isobars to properly account for mass transfer in the SuperCritical (SC) Fluid Extraction (SCFE) processes. A reliable sorption isotherm/isobar model is a requirement, on one hand, for the determination of relevant inner mass transfer coefficients in SC CO2 extractions of vegetable substrates and other biological materials at the laboratory scale, and on the other hand, for a simulation tool successfully applicable to describe industrial SCFE process, which should be based both on a reliable mathematical descriptions of SC CO2 extraction processes. Having a reliable simulation model and model parameters would allow limiting expensive experimental pilot-scale work to validation purposes. Based on simulations of oil extraction from pre-pressed oilseeds using SC CO2 at 353K and 90MPa, this manuscript shows that the initial oil content in the pre-treated seed affects the apparent solubility of the oil, that the partition of the oil between the seed and CO2 affects oil yield, that it is difficult to discriminate oil partition from inner mass transfer effects, that the best-fit parameters from a mathematical model are adequate only when the model accounts for the true physical picture of the extraction process, and that failure of the mathematical model to account the true physical picture of the extraction process impedes reliable simulations, scale-up, and economical evaluation of industrial SCFE process. Being sorption phenomena of such paramount importance to build a reliable mathematical model for simulation of SCFE processes, this manuscript proposes a mathematical model that fits experimental sorption isotherm/isobars for oil from seeds. [Copyright &y& Elsevier]

Offers a look at the permeability and diffusivity levels of carbon dioxide (CO2) through paper packaging with increasing hydration. Methodology of the study; Instrument used in measuring the permeability and diffusivity levels of CO2; Reason for using the water sorption isotherms in the study.

Supercritical carbon dioxide (scCO2) was used to extract components of interest from Scenedesmus dimorphus, a microalgae species, under varied algal harvesting and extraction conditions. Liquid chromatography-mass spectrometry (LC-MS) was used to quantify the concentration of fatty acid methyl esters (FAME) and the FAME profile of transesterified lipids, phospholipids and pigments extracted under varied supercritical temperatures and pressures. The scCO2extraction results are compared with conventional solvent extraction to evaluate differences in the efficiency and nature of the extracted materials. Algae harvested by centrifugation (vs.lyophilization) demonstrated a similar extraction efficiency in scCO2, indicating potential energy benefits by avoiding conventional algal mass dehydration prior to extraction. Centrifuged algae and optimized extraction conditions (6000 psi; 100 °C) resulted in comparable FAME yields to conventional processes, as well as increased selectivity, reflected in the decreased pigment, nitrogen and phospholipid contamination of the FAME. Cell pre-treatments—sonication, microwave, bead beating and lyophilization—showed an enhancement in extraction yield in both conventional solvent and scCO2extraction, allowing for improved extraction efficiencies. This study suggests that scCO2, a green solvent, shows great potential for algal lipid extraction for the sustainable production of biodiesel. [ABSTRACT FROM AUTHOR]

Mesoporous carbon nitrides (MCN) were prepared by a nano-casting method using mesoporous silica as a template with different carbon and nitrogen sources like melamine only (MS-MCN), urea-formaldehyde (UF-MCN) and melamine-glyoxal (MG-MCN). These mesoporous carbon nitride materials possess nitrogen moieties which behave like a CO2-philic surface facilitating oxidation of cyclic olefins by molecular oxygen in the co-presence of CO2below supercritical conditions. The co-presence of CO2augmented the conversions of cyclic olefins at low pressures of CO2, depicting a promotional effect. Approaches towards quantification of promotional effects and insights into the promotional aspects have been studied. [ABSTRACT FROM AUTHOR]

The continuous biocatalytic synthesis of (R)-2-octanol carried out in an enzyme membrane reactor showed an excellent process stability of the biocatalysts, resulting in a turnover number of 15 million for the applied alcohol dehydrogenase. Utilisation of the ionic liquid AMMOENG™ 101 as a feasible cosolvent increased substrate concentration, and improved space time yields and turnover numbers of the cofactor by factors of 3 and 6, respectively. Moreover, 80% less waste was generated, while producing the same amount of product. Integrated product separation was realized viasolid phase extraction. Extraction of the applied solid phase with supercritical carbon dioxide allowed more than 30 reuses of the solid phase. [ABSTRACT FROM AUTHOR]

TiO2catalysts of anatase, rutile and brookite phase were prepared at low temperature and tested for carrying out the photocatalytic partial oxidation of 4-methoxybenzyl alcohol to 4-methoxybenzaldehyde (p-anisaldehyde) in organic-free water suspensions. Traces of 4-methoxybenzoic acid and open-ring products were the only by-products present, CO2being the other main oxidation product. Rutile exhibited the highest yield to p-anisaldehyde (62% mol) at a rate of the same order of magnitude of that showed by the other samples. Commercial rutile and anatase photocatalysts were also used for the sake of comparison. The samples have been characterised by an in situATR-FTIR investigation carried out in conditions simulating the photoreaction ones. [ABSTRACT FROM AUTHOR]

Selective oxidation of tetralin by molecular oxygen over mesoporous CrMCM-41 molecular sieve catalyst using supercritical carbon dioxide (scCO2) solvent has been investigated. CrMCM-41 catalyst gave high selectivity (96.2%) and good yield (63.4%) of 1-tetralone. The presence of scCO2medium improves 1-tetralone selectivity and suppresses leaching of chromium from the CrMCM-41. The activity over recycled CrMCM-41 remains nearly the same under the present experimental conditions. The effect of the reaction parameters on CrMCM-41 was also studied in detail along with comparison of its catalytic activities with other mesoporous catalysts, viz.MnMCM-41, CoMCM-41, microporous CrAPO-5, CoMFI, and macroporous Cr/SiO2catalyst, respectively. In addition this catalytic system was also applied for the oxidation of other benzylic compounds such as indane, fluorene, acenaphthene and diphenylmethane. [ABSTRACT FROM AUTHOR]

Development of nutritional energetics can be traced to the 1400s. Lavoisier established relationships among O2 use, CO2 production and heat production in the late 1700s, and the laws of thermodynamics and law of Hess were discovered during the 1840s. Those discoveries established the fundamental bases for nutritional energetics and enabled the fundamental entity ME = retained energy + heat energy to be established. Objectives became: 1) to establish relationships between gas exchange and heat energy, 2) to devise bases for evaluation of foods that could be related to energy expenditures, and 3) to establish causes of energy expenditures. From these endeavors, the basic concepts of energy partitioning by animals were developed, ultimately resulting in the development of feeding systems based on NE concepts. The California Net Energy System, developed for finishing beef cattle, was the first to be based on retained energy as determined by comparative slaughter and the first to use 2 NE values (NEm and NEg) to describe feed and animal requirements. The system has been broadened conceptually to encompass life cycle energy requirements of beef cattle and modified by the inclusion of numerous adjustments to address factors known to affect energy requirements and value of feed to meet those needs. The current NE system remains useful but is empirical and static in nature and thus fails to capture the dynamics of energy utilization by diverse animals as they respond to changing environmental conditions. Consequently, efforts were initiated to develop dynamic simulation models that captured the underlying biology and thus were sensitive to variable genetic and environmental conditions. Development of a series of models has been described to show examples of the conceptual evolution of dynamic, mechanistic models and their applications. Generally with each new system, advances in prediction accuracy came about by adding new terms to conceptually validated models. However, complexity of input requirements often limits general use of these larger models. Expert systems may be utilized to provide many of the additional inputs needed for application of the more complex models. Additional information available from these systems is expected to result in an ever-increasing range of application. These systems are expected to have increased generality and the capability to be integrated with other models to allow economic evaluation. This will eventually allow users to compute solutions that allow development of optimal production strategies. [ABSTRACT FROM AUTHOR]

Nitrogen cycling in northern temperate forest ecosystems could change under increasing atmospheric CO2 and tropospheric O3 as a result of quantitative and qualitative changes in plant litter production. At the Aspen Free Air CO2–O3 Enrichment (FACE) experiment, we previously found that greater substrate inputs to soil under elevated CO2 did not alter gross N transformation rates in the first 3 years of the experiment. We hypothesized that greater litter production under elevated CO2 would eventually cause greater gross N transformation rates and that CO2 effects would be nullified by elevated O3. Following our original study, we continued measurement of gross N transformation rates for an additional four years. From 1999 to 2003, gross N mineralization doubled, N immobilization increased 4-fold, but changes in microbial biomass N and soil total N were not detected. We observed year-to-year variation in N transformation rates, which peaked during a period of foliar insect damage. Elevated CO2 caused equivalent increases in gross rates of N mineralization (+34%) and NH immobilization (+36%). These results indicate greater rates of N turnover under elevated CO2, but do not indicate a negative feedback between elevated CO2 and soil N availability. Elevated O3 decreased gross N mineralization (−16%) and had no effect on NH immobilization, indicating reduced N availability under elevated O3. The effects of CO2 and O3 on N mineralization rates were mainly related to changes in litter production, whereas effects on N immobilization were likely influenced by changes in litter chemistry and production. Our findings also indicate that concomitant increases in atmospheric CO2 and O3 could lead to a negative feedback on N availability. [ABSTRACT FROM AUTHOR]

• Concentrations of atmospheric CO2 and tropospheric ozone (O3) are rising concurrently in the atmosphere, with potentially antagonistic effects on forest net primary production (NPP) and implications for terrestrial carbon sequestration. • Using free-air CO2 enrichment (FACE) technology, we exposed north-temperate forest communities to concentrations of CO2 and O3 predicted for the year 2050 for the first 7 yr of stand development. Site-specific allometric equations were applied to annual nondestructive growth measurements to estimate above- and below-ground biomass and NPP for each year of the experiment. • Relative to the control, elevated CO2 increased total biomass 25, 45 and 60% in the aspen, aspen–birch and aspen–maple communities, respectively. Tropospheric O3 caused 23, 13 and 14% reductions in total biomass relative to the control in the respective communities. Combined fumigation resulted in total biomass response of −7.8, +8.4 and +24.3% relative to the control in the aspen, aspen–birch and aspen–sugar maple communities, respectively. • These results indicate that exposure to even moderate levels of O3 significantly reduce the capacity of NPP to respond to elevated CO2 in some forests. [ABSTRACT FROM AUTHOR]

To determine the effect of morphine and flunixin meglumine on isoflurane (ISO) minimum alveolar concentration (MAC) in goats. Prospective, randomized experimental study. Five adult, wether goats from 1 to 3 years in age, and weighing 24–65 kg. Anesthesia was induced using ISO, which was delivered via a mask. Goats were intubated and ventilated to maintain an end-tidal carbon dioxide concentration between 25 and 30 mm Hg (3.3–4 kPa). End-tidal ISO concentration was measured using an infrared analyzer. The baseline ISO MAC that prevented purposeful movement in response to clamping a claw was determined. Following baseline MAC determination, each goat received one of the following four treatments intravenously (IV): morphine (2 mg kg−1), flunixin (1.5 mg kg−1), flunixin (1.5 mg kg−1) plus morphine (2 mg kg−1) or saline, and the MAC was re-determined. Goats were studied at weekly intervals, and each goat received each treatment in a randomized fashion. The baseline ISO MAC for the control treatment was 1.43%. Morphine reduced the MAC by 29.7%. Flunixin did not significantly decrease the MAC nor did it potentiate the effect of morphine on MAC. The quality of recovery was good in all cases. Morphine (2 mg kg−1, IV) significantly reduced the ISO MAC in goats and did not adversely affect the quality of recovery. The use of morphine, at the dose studied, in association with ISO anesthesia, will allow a clinically significant reduction in the concentration of ISO required to maintain general anesthesia in goats. [ABSTRACT FROM AUTHOR]

We show here that luminal mucus from the colon and the stomach of guinea pigs, mice and humans exhibits substantial carbonic anhydrase (CA) activity, by which the velocity of the CO2 hydration reaction is accelerated 1000–2000-fold, approximately 1/10 of what is found in the red cell. Although this CA shares several properties with CA II, studies with CA II-deficient mice show that gastrointestinal mucus CA is not affected in these animals and thus does not appear to be CA II. We speculate that the mucus layer covering the luminal surface of gastrointestinal epithelium can, due to the presence of CA, maintain a normal tissue pCO2 in the epithelium, even when the pCO2 values in the lumen are much higher, as is known for stomach and colon. To test this hypothesis, we have developed a mathematical model which describes (a) diffusion of CO2 and HCO3− across the mucus layer and (b) H+ transport mediated by continuous secretion of mucus, which due to its high H+ buffer capacity transports H+ by convection towards the lumen. The model predicts that continuous transport of the reaction products of CO2 towards the lumen, by diffusion and convection, protects the epithelium against high CO2 partial pressures in the lumen. [Copyright &y& Elsevier]

• 3D integrated Sn/CNT@N C gas diffusion electrode is proposed by phase inversion. • CNT@N C has integrated sponge-like microporous and finger-like macroporous layers. • The co-catalysis of N improves electron-proton-gas transfer for high performance. • Faraday efficiency of formate and CO is improved compared with Sn/carbon paper. A 3D integrated hierarchical porous N-doped Sn/CNT@N C gas diffusion electrode is proposed via phase inversion to synergistically improve electron-proton-gas transfer and efficiency of CO 2 reduction reaction (CO2RR). Hierarchical porous structure is tuned by the carbon nanotube additive during phase inversion, which integrates microporous layer and diffusion layer to decrease mass transfer resistance comparing with the 2D layer structure of commercial carbon paper. XPS results show that Sn/CNT@N C 800 contains pyridinic nitrogen and pyrrolic nitrogen with catalytic activity. EIS and LSV curves show that Sn/CNT@N C 800 is beneficial to reduce mass transfer resistance and increase current density after twice hydrophobic treatments. As a result, Sn/CNT@N C 800 shows higher CO 2 RR electrocatalytic activity. The reaction rate and Faraday efficiency of CO at 12 mA cm−2 increase by 40.2% and 40.6%, respectively compared with Sn/carbon paper. The reaction rate and Faraday efficiency of formate are also slightly higher than those of Sn/carbon paper. [Display omitted] [ABSTRACT FROM AUTHOR]

Constructing nanoscale coordination polymers (CPs) with different micro- or nanoscale morphologies and sizes is crucial for the functionalization of CPs-based heterogeneous catalysts. Herein, surfactant polyvinylpyrrolidone (PVP), surface-supported frameworks (filter paper or Ni foam), and Co-based CPs (1), [Co 2 (pdpa)(py) 4 (H 2 O)] n (H 4 pdpa ​= ​5,5'-(pentane-1,2-diyl)-bis(oxy)diisophthalic; py ​= ​pyridine)) were employed to develop highly ordered micro- or nanoscale CPs, achieving microscale 1a (without surface-supported framework) and nanoscale 1b-c (filter paper and Ni foam as surface-supported frameworks for 1b and 1c , respectively). Furthermore, the catalytic performance of nanoscale 1c with spheric particles for the tandem conversion reactions of aromatic nitriles and diamines into imidazoline or tetrahydropyrimidine frameworks was much more prominent than that of large scale 1 , microscale 1a , and nanoscale 1b because of the easily accessible catalytic active sites in the nanoscale spheric particles, which offered a functionalizable platform for the tandem reactions by minimizing the diffusion distance but did little for their activity. By introducing surfactant and surface-supported frameworks, different morphologies and particle sizes of Co-based CPs with micro- or nanoscale 1a-c were constructed and were used as efficient heterogeneous catalysts to execute tandem conversion reactions. [Display omitted] • A new Co-based CPs was constructed under solvothermal conditions. • Co-based CPs with different morphologies and particle sizes were obtained. • The catalytic performance of all the prepared particles for tandem reactions was conducted. [ABSTRACT FROM AUTHOR]

This comment addresses several points regarding data interpretation in a recent paper in the Journal, which results in an inaccurate interpretation of experimental data on CO 2 diffusion in water. The experimental data were interpreted by Fick's law of diffusion, while the existence of convection was disregarded. [ABSTRACT FROM AUTHOR]

Natural colorimetric indicators have been fabricated using annatto and pomegranate extract powder and compared with chemical colorimetric indicator fabricated using bromophenol blue (BPB) to monitor the freshness of ready‐to‐cook (RTC) idli batter. The fabricated colorimetric indicator labels work on increasing headspace carbon dioxide (CO2) concentration and decreasing pH of stored batter, where indicators showed visible color change from lightest to darkest for spoiled samples. The headspace CO2 concentration of RTC idli batter increased from 0.15 ± 0.05 to 18.07 ± 0.21% (v/v) and pH decreased from 6.7 ± 0.06 to 4.5 ± 0.06 at optimum storage condition (35 ± 1°C) up to 24 h. The percent titratable acidity (% TA) increased from 0.44 ± 0.02 to 0.90 ± 0.02% up to 24 h. The viable lactic acid bacteria count (LABC) and total bacterial count (TBC) increased while yeast and mold count (YMC) was decreased with increasing fermentation time up to 24 h for batter stored at optimum condition. The color change of indicators was quantitatively measured with captured red, green, and blue (RGB) images. Pixel intensity for natural and chemical colorimetric indicators were decreased with increasing fermentation time. The leaching of chemical dye was observed on stored batter, and natural colorimetric indicators are nontoxic and successfully used as "on package sticker" for monitoring freshness of RTC idli batter. [ABSTRACT FROM AUTHOR]

This paper reviews the application of carbonation technology to the environmental industry as a way of reducing carbon dioxide (CO(2)), a green house gas, including the presentation of related projects of our research group. An alternative technology to very slow natural carbonation is the co-called 'accelerated carbonation', which completes its fast reaction within few hours by using pure CO(2). Carbonation technology is widely applied to solidify or stabilize solid combustion residues from municipal solid wastes, paper mill wastes, etc. and contaminated soils, and to manufacture precipitated calcium carbonate (PCC). Carbonated products can be utilized as aggregates in the concrete industry and as alkaline fillers in the paper (or recycled paper) making industry. The quantity of captured CO(2) in carbonated products can be evaluated by measuring mass loss of heated samples by thermo-gravimetric (TG) analysis. The industrial carbonation technology could contribute to both reduction of CO(2) emissions and environmental remediation.

Currently, developing highly active and low-cost electrocatalytic materials for oxygen evolution reaction (OER) is an enormously grand challenge. Herein, we developed a novel and highly active Mn doped Co 2 Fe layer double hydroxide (LDH) electrocatalyst for OER. We discovered that these electrocatalytic materials can be directly grown on carbon papers to construct high-specific-surface-area electrode, which shows the lowest overpotential of 266 mV at 10 mA cm−2. Furthermore, after introducing Mn element, DFT + U calculation found that the ∗OOH of Fe-site on Co 2 Fe 0.67 Mn 0.33 LDH could draw more electrons than Co 2 Fe LDH due to the electronegativity differences between Fe-site on Co 2 Fe 0.67 Mn 0.33 LDH and Fe-site on Co 2 Fe LDH, which is reason that the energy level of Fe 3d (e g) was obviously downshifted by d-d repulsion of Mn 3d and Fe 3d in the neighboring sites of Co 2 Fe 0.67 Mn 0.33 LDH after doped Mn element, which leads to reduce charge-transfer energy from O 2p to Fe 3d (e g) to promote oxygen evolution processes for OER. Meanwhile, the band gap is also decreased after doped Mn element in Co 2 Fe LDH due to the downshifted e g orbital energy of Fe 3d. This study gives a general avenue to design and developing efficiently active LDH electrocatalysts for OER in the future. • Both bimetallic CoFe LDH and Mn doped CoFe LDHs directly grown on carbon paper are successfully synthesized. • The Co 2 Fe 0.67 Mn 0.33 LDH@NFs exhibits a small overpotential of 236 mV at 10 mA cm−1 for OER. • DFT + U studies reveal that the observed superb OER activity could be attributed to d-d repulsion of Mn 3d and Fe 3d. [ABSTRACT FROM AUTHOR]

This study aimed to maximise the amount of CO2 storage by indirect carbonation using paper sludge ash (PSA), which is an alkaline industrial waste. The properties of the following three types of solvents were considered: acids (acetic acid and hydrochloric acid), ammonium salts (ammonium chloride and ammonium acetate) and others (sodium citrate and water). When carbon dioxide was injected into calcium leachates prepared from PSA using acids, carbonation did not occur, and using ammonium salts as solvent, the carbonation efficiency was low. However, after pH swing of the leachates using sodium hydroxide and ammonia solution for acid and ammonium salt solvents, up to 324 kg CO2/(ton PSA) and 175 kg CO2/(ton PSA) were stored, respectively. When carbon dioxide was injected into calcium leachates prepared from PSA using sodium citrate or water, solid was initially generated which later dissolved. In order to solve this problem, CO2 injection was stopped just before the pH of the solution reached 10.5 for sodium citrate and 8.3 for water, resulting in the storage of 136 kg CO2/(ton PSA) and 29 kg CO2/(ton PSA), respectively. Solids obtained through carbonation were pure calcium carbonate. [ABSTRACT FROM AUTHOR]

Litter decay dynamics of paper birch (Betula papyrifera) were assessed at the Aspen free-air CO2 enrichment (FACE) facility in northern Wisconsin, USA. Leaf litter was decomposed for 12 months under factorial combinations of 360 vs. 560 μL CO2 L−1, crossed with 36 vs. 55 nL O3 L−1. To differentiate between substrate quality and environment effects, litterbags were placed in their Native Plots of origin or transplanted into the other treatments. CO2 enrichment, regardless of O3 concentration, produced poorer quality litter (high C/N, lignin/N and condensed tannins) than did ambient CO2 (low C/N, lignin/N and condensed tannins). Substrate quality differences were reflected in the mass loss rates (k-values), which were high for litter generated under ambient CO2 (0.887 year−1) and low for litter generated under elevated CO2 (0.674 year−1). The rate-retarding effects of CO2 enrichment were neither alleviated nor exacerbated by O3 exposure. Decay rates varied, however, depending on whether litter was placed back into its plot of origin or transplanted to Common Gardens. The results of this study are species specific, but they have important implications for understanding the processes regulating storage of fixed C and the release of CO2 from northern forest ecosystems. [ABSTRACT FROM AUTHOR]

Details a study which examined the accumulation of H2O2 within the leaf mesophyll of Populus tremuloides aspen genotypes and seedlings of paper birch Betula papyrifera. Gene expression of catalase; Effects of ozone and carbon dioxide on the structure of ozone-tolerant aspen; Correlation between aspen clones, elevated ozone, birch and peroxisomes levels.