The Carbon Footprint of Games Distribution

This research investigates the carbon footprint of the lifecycle of console games, using the example of PlayStation®3 distribution in the UK. We estimate total carbon equivalent emissions for an average 8.8‐gigabyte (GB) game based on data for 2010. The bulk of emissions are accounted for by game play, followed by production and distribution. Two delivery scenarios are compared: The first examines Blu‐ray discs (BDs) delivered by retail stores, and the second, games files downloaded over broadband Internet. Contrary to findings in previous research on music distribution, distribution of games by physical BDs results in lower greenhouse gas emissions than by Internet download. The estimated carbon emissions from downloading only fall definitively below that of BDs for games smaller than 1.3 GB. Sensitivity analysis indicates that as average game file sizes increase, and the energy intensity of the Internet falls, the file size at which BDs would result in lower emissions than downloads could shift either up‐ or downward over the next few years. Overall, the results appear to be broadly applicable to title games within the European Union (EU), and for larger‐than‐average sized games in the United States. Further research would be needed to confirm whether similar findings would apply in future years with changes in game size and Internet efficiency. The study findings serve to illustrate why it is not always true that digital distribution of media will have lower carbon emissions than distribution by physical means when file sizes are large.     

Implications of corn prices on water footprints of bioethanol

Previously reported water footprints (WFPs) of corn ethanol have been estimated based on the assumption that corn ethanol feedstock could be supplied by the same states where the corn is grown. However, ethanol conversion facilities may choose out-of-state feedstock suppliers depending on the total price of feedstock they have to pay including both the corn price and transportation costs. The purpose of this study is to evaluate the WFPs and total water use (TWU) of corn ethanol considering an optimal allocation of corn with heterogeneous corn feedstock prices across states. The results show that the WFPs of corn ethanol are less than 100 l of water per liter of ethanol (Lw/Le) for all ethanol-producing states based on both the 2008 corn price and transportation costs for rail and truck. Results also reveal that WFPs are very sensitive to the market price of corn and that additional greenhouse gas emissions due to corn trade between states are not significant.     

基于生态足迹修正模型的江苏省海洋经济可持续发展分析

基于生态足迹的理论和方法,提出海洋生态足迹的概念,并根据江苏省海洋环境的特殊性,构建了渔业用海、交通运输用海、工程建筑用海、能源用海、滩涂5个海洋生态足迹子模型,采用改进熵值法确定5类用海的均衡因子,分析了2000-2008年江苏省海洋生态足迹和生态承载力.结果表明:2000-2008年间,江苏省人均海洋生态足迹增幅近7倍,从36.90 hm2上升到252.94 hm2;人均生态承载力从105.01 hm2增至185.49 hm2,呈平稳增长态势;2000年,江苏省海洋环境处于生态盈余状态,海洋经济呈弱可持续发展状态,2004年,海洋生态环境急剧恶化,生态赤字高达109660.5 hm2,海洋经济可持续能力下降.渔业用海的高生态足迹是造成江苏省海洋生态赤字的主要原因,滩涂是维持江苏省海洋经济可持续发展的重要后备资源.     

Life Cycle of Titanium Dioxide Nanoparticle Production

Life cycle impact of emissions, energy requirements, and exergetic losses are calculated for a novel process for producing titanium dioxide nanoparticles from an ilmenite feedstock. The Altairnano hydrochloride process analyzed is tailored for the production of nanoscale particles, unlike established commercial processes. The life cycle energy requirements for the production of these particles is compared with that of traditional building materials on a per unit mass basis. The environmental impact assessment and energy analysis results both emphasize the use of nonrenewable fossil fuels in the upstream life cycle. Exergy analysis shows fuel losses to be secondary to material losses, particularly in the mining of ilmenite ore. These analyses are based on the same inventory data. The main contributions of this work are to provide life cycle inventory of a nanomanufacturing process and reveal potential insights from exergy analysis that are not available from other methods.     

Seasonal Distribution of Antlered Sculpin, <Emphasis Type="Italic">Enophrys diceraus</Emphasis> (Cottidae) in Peter the Great Bay,Sea of Japan

The antlered sculpin Enophrys diceraus in Peter the Great Bay is found to inhabit from shallow waters to depths deeper than 600 m. The range of depth where this species occurs is the narrowest, from 12 to 250 m deep, in summer. The greatest depths of inhabitation are characteristic, in all seasons, only of adult fish of this species. In the cold period of the year, the young probably avoid the upper part of the shelf where the temperatures have cooled down to negative numbers. Spawning in the antlered sculpin begins in the second half of November. Females dominate the population of this species inhabiting Peter the Great Bay. Males reach 38 cm long and more; females can be up to 31 cm long. The greatest density of antlered sculpin in the summer period on the preferred substrates is observed in the western part of the bay, primarily on sandy ground.     

Foraging behaviour of western sandpipers changes with sediment temperature: implications for their hemispheric distribution

Migratory shorebirds need to replenish their energy reserves by foraging at stop-over sites en route. Adjusting their foraging behaviour to accommodate variation in local prey availability would therefore be advantageous. We test whether western sandpipers (Calidris mauri), a sexually dimorphic shorebird, adjust their foraging behaviour in response to local changes in prey availability, as inferred by changes in diurnal time and sediment temperature. Both males and females showed quantitative changes to foraging mode in relation to each of these variables. Probing, for example, which is used to exploit infaunal prey, was significantly more common at higher temperatures. The results presented here are consistent with the notion that western sandpipers can adjust their foraging behaviour in response to variation in prey availability. Further, we speculate that temperature-induced changes to prey location may contribute to the striking sexual segregation observed for this species during the non-breeding season.     

Response of wetland plant species to hydrologic conditions

Understanding hydrologic requirements of native and introduced species is critical to sustaining native plant communities in wetlands of disturbed landscapes. We examined plant assemblages, and 31 of the most common species comprising them, from emergent wetlands in an urbanizing area of the Pacific Northwest, USA, in relation to in situ, fine-scale hydrology. Percent cover by plant species was estimated in 2208 1-m² plots across 43 sites, with water depth at time of vegetation sampling measured in 432 plots. Three years of bi-weekly hydrologic data from each of the 43 sites were used to estimate mean surface water level and mean absolute difference (MAD) in surface water level for every plot. Nine assemblages of plant species that co-occur in the field were identified using TWINSPAN. The assemblage richest in native species occurred under intermediate hydrologic conditions and was bracketed by pasture grass dominated assemblages at drier conditions with low water level variability, and Phalaris arundinacea L. assemblages with higher mean water levels and variability. Results suggest minor changes in average water levels (10 cm) or in variability (±2 cm in MAD) could promote a shift from assemblages dominated by natives to those dominated by invasive or alien taxa. Canonical correspondence analysis segregated the species into four groups related to hydrologic gradients. Each species response group was typified by taxa with similar optima for a given environmental variable, with each group related to a characteristic suite of hydrologic conditions. The most common species (P. arundinacea, Juncus effusus L., and Typha latifolia L.), each representing a different response group, exhibited unique responses in occurrence/abundance in relation to water level variability, but were abundant over a wide range of water depth. The realized niches of other species in each response group were more restricted, with peaks in cover confined to narrower ranges of water depth and variability.     

A multi-scale perspective of water pulses in dryland ecosystems: climatology and ecohydrology of the western USA

In dryland ecosystems, the timing and magnitude of precipitation pulses drive many key ecological processes, notably soil water availability for plants and soil microbiota. Plant available water has frequently been viewed simply as incoming precipitation, yet processes at larger scales drive precipitation pulses, and the subsequent transformation of precipitation pulses to plant available water are complex. We provide an overview of the factors that influence the spatial and temporal availability of water to plants and soil biota using examples from western USA drylands. Large spatial- and temporal-scale drivers of regional precipitation patterns include the position of the jet streams and frontal boundaries, the North American Monsoon, El Niño Southern Oscillation events, and the Pacific Decadal Oscillation. Topography and orography modify the patterns set up by the larger-scale drivers, resulting in regional patterns (10²–10⁶ km²) of precipitation magnitude, timing, and variation. Together, the large-scale and regional drivers impose important pulsed patterns on long-term precipitation trends at landscape scales, in which most site precipitation is received as small events (<5 mm) and with most of the intervals between events being short (<10 days). The drivers also influence the translation of precipitation events into available water via linkages between soil water content and components of the water budget, including interception, infiltration and runoff, soil evaporation, plant water use and hydraulic redistribution, and seepage below the rooting zone. Soil water content varies not only vertically with depth but also horizontally beneath versus between plants and/or soil crusts in ways that are ecologically important to different plant and crust types. We highlight the importance of considering larger-scale drivers, and their effects on regional patterns; small, frequent precipitation events; and spatio-temporal heterogeneity in soil water content in translating from climatology to precipitation pulses to the dryland ecohydrology of water availability for plants and soil biota.     

Growth dynamics and biomass allocation of Eleocharis sphacelata at different water depths: observations, modeling, and applications

Imbalanced biomass allocation patterns in emergent aquatic plants to above and below-ground structures as a response to climatic variations and water depth were investigated on the basis of observation of three stable homogeneous populations established under different water regimes and climatic environments in Goulburn and Ourimbah, New South Wales, Australia, from August 2003 to December 2004. The growth of shoots depended on water inundation-drawdown patterns and climatic variations. Shoot density was greater in shallow water but with shorter shoot length and less maximum above-ground biomass density than for plant stands in deep water. Deep-water populations attained higher below-ground biomass with higher above to below-ground biomass ratio than for the shallow-water population. Translocation of carbohydrate reserves between above and below-ground organs in deep-water populations were mostly downward throughout the year whereas the depletion–recharge pattern varied seasonally in shallow water populations. Shoots of deep-water populations grew year-round whereas in shallow water shoots died off after recession of the water level with no re-growth afterward, showing that Eleocharis sphacelata is better adapted to deep water and is stressed under shallow-water conditions. A mathematical model was formulated to describe the growth patterns of E. sphacelata and subsequently to predict the effect of water depth on production. Model simulations are in satisfactory agreement with observed patterns of growth. The model also predicts that maximum production decreases sharply with increasing water depth.     

Soil organic carbon changes as influenced by agricultural land use and management: a case study in Yanhuai Basin, Beijing, China

The effects of agricultural land use and management practices on soil organic carbon (SOC) are of great concern. In this study, SOC changes were investigated in sandy loam soils (Ustochrepts, USDA Soil Taxonomy) under orchard, vegetable, corn (Zea maize L.), and soybean (Glycine max L.) cultivation in northern China. The corn fields were further classified into three categories based on their inputs, i.e. high-input, mid-input, and low-input corn fields. In April 2005, a total of 197 soil samples were collected from 42 soil sites within 100 cm soil depth in Yanhuai Basin, Beijing, China. SOC contents were determined using rapid dichromate oxidation, and ANOVA statistical analysis was used to test the significances between land use and management practices at p<0.05. The results showed that: (1) the effects of land use and management practices on SOC primarily occurred within the topsoil (0–25 cm), and the SOC contents sharply decreased with the increase in soil depth. (2) SOC content and density values of orchard, vegetable, and high-input corn fields were higher than those of soybean, mid- and low-input corn fields.