Greenhouse gas emissions from a Cu-contaminated soil remediated by in situ stabilization and phytomanaged by a mixed stand of poplar,willows, and false indigo-bush

Phytomanagement of trace element-contaminated soils can reduce soil toxicity and restore soil ecological functions, including the soil gas exchange with the atmosphere. We studied the emission rate of the greenhouse gases (GHGs) CO₂, CH₄, and N₂O; the potential CH₄ oxidation; denitrification enzyme activity (DEA), and glucose mineralization of a Cu-contaminated soil amended with dolomitic limestone and compost, alone or in combination, after a 2-year phytomanagement with a mixed stand of Populus nigra, Salix viminalis, S. caprea, and Amorpha fruticosa. Soil microbial biomass and microbial community composition after analysis of the phospholipid fatty acids (PLFA) profile were determined. Phytomanagement significantly reduced Cu availability and soil toxicity, increased soil microbial biomass and glucose mineralization capacity, changed the composition of soil microbial communities, and increased the CO₂ and N₂O emission rates and DEA. Despite such increases, microbial communities were evolving toward less GHG emission per unit of microbial biomass than in untreated soils. Overall, the aided phytostabilization option would allow methanotrophic populations to establish in the remediated soils due to decreased soil toxicity and increased nutrient availability.     

A method for assessing sustainability,with beef production as an example

A comprehensive approach to decisions about the use of land and other world resources, taking full account of biological and other scientific information, is crucial for good decisions to be made now and in future. The sustainability of systems for producing food and other products is sometimes assessed using too narrow a range of component factors. A production system might be unsustainable because of adverse effects on a wide range of aspects of human welfare, animal welfare, or the environment. All factors should be included in sustainability evaluation, otherwise products or actions might be avoided without adequate consideration of key factors or of the diversity of production systems. A scoring method that is based on scientific information and potentially of general relevance is presented here, using beef production as a example with a review of each of its sustainability components. This includes an overall combined score and specific factors that make the system unacceptable for some consumers. The results show that, in this example, the sustainability of the best systems is very much better than that of the worst systems. By taking account of scores for a wide range of components of sustainability in comparing beef-production systems, better quality policies about beef use can be formulated than when statements referring only to one system are considered. The least sustainable beef-production systems are extensive grazing that causes land degradation and the use of feedlots or indoor housing with grain feeding. Semi-intensive silvopastoral systems are the most sustainable beef-production systems, and well-managed pasture-fed beef from areas where crop production is uneconomic is also sustainable. This simple, scientifically based scoring system could be modified to use positive as well as negative scores and is of value for policy makers, researchers, producers, organisations aiming to improve sustainability, and the general public.     

Laboratory bioassay and greenhouse evaluation of Trichogramma cordubensis strains from Portugal

A simple, inexpensive chamber was developed and tested as an evaluative tool to monitor Trichogramma cordubensis dispersal in the laboratory. The chamber consisted of a continuous, winding channel which was cut into an aluminum block. Wasps were released at one end of the channel and allowed to walk in the channel for 21 h and to parasitize Mamestra brassicae eggs placed 3.4 m from the point of wasp introduction. Comparisons between two T. cordubensis populations demonstrated that one population (TCM) dispersed more in the chamber and located host eggs more successfully than the other population (TCD). Subsequent greenhouse releases confirmed that the TCM population dispersed more readily and had significantly higher parasitism rates on sentinel Ephestia kuehniella eggs on tomato plants. The potential utilization of this chamber as a tool to evaluate quality of Trichogramma populations, mainly dispersal activity, is discussed.     

Variability in greenhouse gas footprints of the global wind farm fleet

While technological characteristics largely determine the greenhouse gas (GHG) emissions during the construction of a wind farm and meteorological circumstances the actual electricity production, a thorough analysis to quantify the GHG footprint variability (in g CO₂eq/kWh electricity produced) between wind farms is still lacking at the global scale. Here, we quantified the GHG footprint of 26,821 wind farms located across the globe, combining turbine-specific technological parameters, life-cycle inventory data, and location- and temporal-specific meteorological information. These wind farms represent 79% of the 651 global wind (GW) capacity installed in 2019. Our results indicate a median GHG footprint for global wind electricity of 10 g CO₂eq/kWh, ranging from 4 to 56 g CO₂eq/kWh (2.5th and 97.5th percentiles). Differences in the GHG footprint of wind farms are mainly explained by spatial variability in wind speed, followed by whether the wind farm is located onshore or offshore, the turbine diameter, and the number of turbines in a wind farm. We also provided a metamodel based on these four predictors for users to be able to easily obtain a first indication of GHG footprints of new wind farms considered. Our results can be used to compare the GHG footprint of wind farms to one another and to other sources of electricity in a location-specific manner.     

Improvements in Life Cycle Energy Efficiency and Greenhouse Gas Emissions of Corn-Ethanol

Corn-ethanol production is expanding rapidly with the adoption of improved technologies to increase energy efficiency and profitability in crop production, ethanol conversion, and coproduct use. Life cycle assessment can evaluate the impact of these changes on environmental performance metrics. To this end, we analyzed the life cycles of corn-ethanol systems accounting for the majority of U.S. capacity to estimate greenhouse gas (GHG) emissions and energy efficiencies on the basis of updated values for crop management and yields, biorefinery operation, and coproduct utilization. Direct-effect GHG emissions were estimated to be equivalent to a 48% to 59% reduction compared to gasoline, a twofold to threefold greater reduction than reported in previous studies. Ethanol-to-petroleum output/input ratios ranged from 10:1 to 13:1 but could be increased to 19:1 if farmers adopted high-yield progressive crop and soil management practices. An advanced closed-loop biorefinery with anaerobic digestion reduced GHG emissions by 67% and increased the net energy ratio to 2.2, from 1.5 to 1.8 for the most common systems. Such improved technologies have the potential to move corn-ethanol closer to the hypothetical performance of cellulosic biofuels. Likewise, the larger GHG reductions estimated in this study allow a greater buffer for inclusion of indirect-effect land-use change emissions while still meeting regulatory GHG reduction targets. These results suggest that corn-ethanol systems have substantially greater potential to mitigate GHG emissions and reduce dependence on imported petroleum for transportation fuels than reported previously.     

Global Climate Change and the Precautionary Principle

The precautionary principle is promoted as a common sense approach that avoids unreasonable delays in taking action. A weak form of the precautionary principle, that action should not wait until all uncertainties are resolved, is indeed common sense and consistent with even the most elementary application of the methods of decision making under uncertainty to the climate change problem. The standard tools of decision analysis imply conclusions consistent with a weak precau tionary principle of taking some action before all the evidence is in. Decision theory also reveals what the basis is for stronger recommendations from the precautionary principle, to the effect that action should be based on the most pessimistic possible interpretation of the future. This conclusion is only possible if prior beliefs are so pessimistic and so strong that they would outweigh any possible new scientific evidence.     

High yield of hydrocarbon gases resulting from pyrolysis of yellow heterotrophic and bacterially degradedChlorella protothecoides

Four kinds of cells ofChlorella protothecoides, green autotrophic cells, bacterially degraded green autotrophic cells, yellow heterotrophic cells and bacterially degraded yellow heterotrophic cells, were used to simulate thermal degradation and gas formation by heating without oxygen at 300°C for 100 h. The yield of pyrolysed hydrocarbon gases in yellow heterotrophic cells with bacterial degradation was 8.5 times higher than that of green autotrophic cells without bacterial degradation. The use of bacterially degraded yellow heterotrophic cells resulted in relatively more lipid and less protein. The results suggest that the hydrocarbon-producing potential of microplanktonic algae in nature may be greater than previously thought based on studies of green autotrophic cells.     

Research advancement in the processes and mechanisms of transporting methane by emerged herbaceous plants and hygrophytes

Methane (CH₄) is an important greenhouse gas, and is involved in atmospheric chemical reactions. Aquatic and hydric environments are important sources of atmospheric CH₄. Majority of CH₄ are transported and released to atmosphere by emerged herbaceous plants and hygrophytes in aquatic and hydric environments. In recent decades, there has been increasing attention on how plants transport CH₄. During CH₄ transportation processes, several interfaces of CH₄ exchange play important roles. First, the tips of lateral roots are primary locations (hotspots) for CH₄ entering the root systems and regulate the gross CH₄ transportation. Then, the diaphragms in the aerenchyma and the root collar impose great resistances for the overall CH₄ transportation processes. In early studies, it was controversial that whether CH₄ emission from plants to atmosphere was controlled by stomas or micropores (small cracks and holes in aboveground part of plant except the blade). Recent studies have confirmed the dominant role of micropores for CH₄ transportation and emission. The dead and damaged stems are widely considered to have positive effects on CH₄ transportation. Diffusion and convection are the two main transporting mechanisms of CH₄, with the efficiency of convection being generally higher than that of diffusion. Both biological (e.g. biomass and photosynthesis) and environmental (e.g. light, temperature and humidity) factors regulate the CH₄ transportation. Many studies have contributed to understanding the CH₄ transportation processes and mechanisms by emerged herbaceous plants and hygrophytes. However, there are still some questions needing further investigations. Issues of consideration may include the operational efficiency in the critical interfaces of CH₄ exchange, the plant parts that play a decisive role in the entire CH₄ transportation, the underlying roles of diffusion and convection on CH₄ interfaces exchanges and entire long distance transports, the combined and coupling effects and mechanisms of biotic and abiotic factors, and the similarities and differences of CH₄ transporting processes and mechanisms among plant species.     

Year-round trap capture of the spotted-wing drosophila,Drosophila suzukii (Diptera: Drosophilidae), in Korean strawberry greenhouses

Korean greenhouse strawberries are mostly cultivated from October to May, which includes the cold winter season. During this time, the population size of the spotted-wing drosophila (SWD), Drosophila suzukii Matsumura (Diptera: Drosophilidae), is expected to decrease in the wild, and is also expected to decrease inside the greenhouses, as long as SWD are not already present inside. Field surveys of SWD have been extensively carried out for field-grown agricultural fruits, but no study has been conducted for greenhouse fruits, such as strawberries. In this study, SWD capture patterns were examined inside and outside of the greenhouse blocks, and in the nearby woodlands in a southwestern locality of Korea using selected traps and attractants for nearly 19 months—in addition to several greenhouse blocks—during the strawberry cultivating periods. The highest capture period was observed from October to mid-December in woodlands, whereas capture number subsequently and sharply decreased up to mid-April, resulting in mostly zero-captures or low captures (≤10). During this period, a zero-capture period was observed inside the greenhouse that lasted for nearly three months (late December to late February). An incubation of the fallen strawberries supported the results of trap capture from inside the greenhouses. Taken together, the occurrence of SWD in the strawberry greenhouses is likely to be highly dependent on that of the nearby woodlands. Thus, a sharp winter drop and the subsequent zero- or low-capture periods in the woodland areas were likely responsible for the observed zero-capture periods inside the greenhouses.