Showing papers in "Frontiers in Environmental Science in 2015"

Prospects and challenges for social media data in conservation science

Abstract: Social media data have been extensively used in numerous fields of science, but examples of their use in conservation science are still very limited In this paper, we propose a framework on how social media data could be useful for conservation science and practice We present the commonly used social media platforms and discuss how their content could be providing new data and information for conservation science Based on this, we discuss how future work in conservation science and practice would benefit from social media data

Outdoor-indoor air pollution in urban environment: challenges and opportunity

Abstract: With the continual improvement in our quality of life, indoor air quality has become an important area of concern in the 21st century. Indoor air quality is affected by many factors including the type and running conditions of indoor pollution sources, ventilation conditions, as well as indoor activities. Studies revealed that the outdoor environment is also an important factor that cannot be neglected for indoor air quality studies. In this review, the indoor and outdoor air pollution relationships obtained from different studies are discussed in order to identify the key factors affecting the indoor air quality. As climate change is recognized as imposing impacts on the environment, how it affects the indoor air quality and the health impacts to the occupants will be evaluated in this paper. The major challenges and opportunities in indoor/outdoor air pollution studies will be highlighted.

Temperature stress and redox homeostasis in agricultural crops

Abstract: Plants are exposed to a wide range of environmental conditions and one of the major forces that shape the structure and function of plants are temperature stresses, which include low and high temperature stresses and considered as major abiotic stresses for crop plants. Due to global climate change, temperature stress is becoming the major area of concern for the researchers worldwide. The reactions of plants to these stresses are complex and have devastating effects on plant metabolism, disrupting cellular homeostasis and uncoupling major physiological and biochemical processes. Temperature stresses disrupt photosynthesis and increase photorespiration altering the normal homeostasis of plant cells. The constancy of temperature, among different metabolic equilibria present in plant cells, depends to a certain extent on a homeostatically regulated ratio of redox components, which are present virtually in all plant cells. Several pathways, which are present in plant cells, enable correct equilibrium of the plant cellular redox state and balance fluctuations in plant cells caused by changes in environment due to stressful conditions. In temperature stresses, high temperature stress is considered to be one of the major abiotic stresses for restricting crop production. The responses of plants to heat stress vary with extent of temperature increase, its duration and the type of plant. On other hand, low temperature as major environmental factor often affects plant growth and crop productivity and leads to substantial crop loses. The present review discusses how oxidative damage as a result of temperature stress is detrimental for various crops. Various strategies adapted by the plants to main redox homeostasis are described along with use of exogenous application of some stress protectants.

Brassinosteroids make plant life easier under abiotic stresses mainly by modulating major components of antioxidant defense system

Abstract: Various abiotic stress factors significantly contribute to major worldwide-losses in crop productivity by mainly impacting plant’s stress tolerance/adaptive capacity. The latter is largely governed by the efficiency of antioxidant defense system for the metabolism of elevated reactive oxygen species (ROS), caused by different abiotic stresses. Plant antioxidant defense system includes both enzymatic (such as superoxide dismutase, SOD, E.C. 1.15.1.1; catalase, CAT, E.C. 1.11.1.6; glutathione reductase, GR, E.C. 1.6.4.2; peroxidase, POD, E.C. 1.11.1.7; ascorbate peroxidase, APX, E.C. 1.11.1.11; guaiacol peroxidase, GPX, E.C. 1.11.1.7) and non-enzymatic (such as ascorbic acid, AsA; glutathione, GSH; tocopherols; phenolics, proline etc.) components. Research reports on the status of various abiotic stresses and their impact on plant growth, development and productivity are extensive. However, least information is available on sustainable strategies for the mitigation of abiotic stress-mediated major consequences in plants. Brassinosteroids (BRs) are a novel group of phytohormones with significant growth promoting nature. BRs are considered as growth regulators with pleiotropic effects, as they influence diverse physiological processes like growth, germination of seeds, rhizogenesis, senescence etc. and also confer abiotic stress resistance in plants. In the light of recent reports this paper: (a) overviews major abiotic stresses and plant antioxidant defense system, (b) introduces BRs and highlights their significance in general plant growth and development, and (c) appraises recent literature available on BRs mediated modulation of various components of antioxidant defense system in plants under major abiotic stresses including metals/metalloids, drought, salinity, and temperature regimes. The outcome can be significant in devising future research in the current direction.

Polyamines as redox homeostasis regulators during salt stress in plants

Abstract: The balance between accumulation of stress-induced polyamines and reactive oxygen species (ROS) is arguably a critical factor in plant tolerance to salt stress. Polyamines are compounds, which accumulate in plants under salt stress and help maintain cellular ROS homeostasis. In this review we first outline the role of polyamines in mediating salt stress responses through their modulation of redox homeostasis. The two proposed roles of polyamines in regulating ROS – as antioxidative molecules and source of ROS synthesis – are discussed and exemplified with recent studies. Second, the proposed function of polyamines as modulators of ion transport is discussed in the context of plant salt stress. Finally, we highlight the apparent connection between polyamine accumulation and programmed cell death induction during stress. Thus polyamines have a complex functional role in regulating cellular signaling and metabolism during stress. By focusing future efforts on how polyamine accumulation and turnover is regulated, research in this area may provide novel targets for developing stress tolerance.

Redox homeostasis in plants under abiotic stress: role of electron carriers, energy metabolism mediators and proteinaceous thiols

Abstract: Contemporaneous presence of both oxidized and reduced forms of electron carriers is mandatory in efficient flux by plant electron transport cascades. This requirement is considered as redox poising that involves the movement of electron from multiple sites in respiratory and photosynthetic electron transport chains to molecular oxygen. This flux triggers the formation of superoxide, consequently give rise to other reactive oxygen species (ROS) under adverse environmental conditions like drought, high or low temperature, heavy metal stress etc. that plants owing during their life span. Plant cells synthesize ascorbate, an additional hydrophilic redox buffer, which protect the plants against oxidative challenge. Large pools of antioxidants also preside over the redox homeostasis. Besides, tocopherol is a liposoluble redox buffer, which efficiently scavenges the ROS like singlet oxygen. In addition, proteinaceous thiol members such as thioredoxin, peroxiredoxin and glutaredoxin, electron carriers and energy metabolism mediators phosphorylated (NADP) and non-phosphorylated (NAD+) coenzyme forms interact with ROS, metabolize and maintain redox homeostasis.

Making the Most of Our Land: Managing Soil Functions from Local to Continental Scale

Abstract: The challenges of achieving both food security and environmental sustainability have resulted in a confluence of demands on land within the European Union (EU): we expect our land to provide food, fibre and fuel, to purify water, to sequester carbon, and provide a home to biodiversity as well as external nutrients in the form of waste from humans and intensive livestock enterprises. All soils can perform all of these five functions, but some soils are better at supplying selective functions. Functional Land Management is a framework for policy-making aimed at meeting these demands by incentivising land use and soil management practices that selectively augment specific soil functions, where required. Here, we explore how the demands for contrasting soil functions, as framed by EU policies, may apply to very different spatial scales, from local to continental scales. At the same time, using Ireland as a national case study, we show that the supply of each soil function is largely determined by local soil and land use conditions, with large variations at both local and regional scales. These discrepancies between the scales at which the demands and supply of soil functions are manifested, have implications for soil and land management: while some soil functions must be managed at local (e.g. farm or field) scale, others may be offset between regions with a view to solely meeting national or continental demands. In order to facilitate the optimisation of the delivery of soil functions at national level, to meet the demands that are framed at continental scale, we identify and categorise 14 policy and market instruments that are available in the EU. The results from this inventory imply that there may be no need for the introduction of new specific instruments to aid the governance of Functional Land Management. We conclude that there may be more merit in adapting existing governance instruments by facilitating differentiation between soils and landscapes.

Redox homeostasis via gene families of ascorbate-glutathione pathway

Abstract: The imposition of environmental stresses on plants brings about disturbance in their metabolism thereby negatively affecting their growth and development and leading to reduction in the productivity. One of the manifestations of abiotic and biotic stress conditions is the enhanced production of reactive oxygen species (ROS) which can be hazardous to cells. Therefore, in order to protect themselves against toxic ROS, plant cells employ the anti-oxidant defense system. The ascorbate-glutathione pathway (Halliwell-Asada cycle) is an indispensible component of the ROS homeostasis mechanism of plants. This pathway entails the antioxidant metabolites: ascorbate, glutathione and NADPH along with the enzymes linking them. The ascorbate-glutathione pathway is functional in different subcellular compartments and all the enzymes of this pathway exist as multiple isoforms. The expression of different isoforms of the enzymes of ascorbate-glutathione pathway is developmentally as well as spatially regulated. Moreover, various abiotic and biotic stress conditions modulate the expression of the enzyme- isoforms differently. It is the intricate regulation of expression of different isoforms of the ascorbate-glutathione pathway enzymes that helps in the maintenance of redox balance in plants under various abiotic and biotic stress conditions. The present review provides an insight into the gene families of the ascorbate-glutathione pathway, shedding light on their role in different abiotic and biotic stress conditions as well as in the growth and development of plants.

A survey of remote-sensing big data

Abstract: We have entered an era of big data. It is popular to refer to the three Vs when characterizing big data: remarkable growths in the volume, velocity and variety of data. However, this statement is too general. Remote-sensing big data has several concrete and special characteristics: multi-source, multi-scale, high-dimensional, dynamic-state, isomer, and non-linear characteristics. This survey explains these characteristics in detail. Furthermore, according to whether the characteristics are closely related to the instruments or methods of data acquisition, we points out that the dynamic-state, multi-scale and non-linear characteristics are intrinsic characteristics of remote-sensing big data while the multi-source, high-dimensional and isomer characteristics are extrinsic characteristics of remote- sensing big data. In addition, we briefly review promising techniques and applications of remote-sensing big data.

Interactions of anthropogenic stress factors on marine phytoplankton

Abstract: Phytoplankton are the main primary producers in aquatic ecosystems. Their biomass production and CO2 sequestration equals that of all terrestrial plants taken together. Phytoplankton productivity is controlled by a number of environmental factors, many of which currently undergo substantial changes due to anthropogenic global climate change. Light availability is an absolute requirement for photosynthesis, but excessive visible and UV radiation impair productivity. Increasing temperatures enhance stratification, decrease the depth of the upper mixing layer exposing the cells to higher solar radiation, and reduce nutrient upward transport from deeper layers. At the same time, stratospheric ozone depletion exposes phytoplankton to higher solar UV-B radiation especially in polar and mid latitudes. Terrestrial runoff carrying sediments and dissolved organic matter into coastal waters leads to eutrophication while reducing UV penetration. All these environmental forcings are known to affect physiological and ecological processes of primary producers. Ocean acidification due to increased atmospheric CO2 concentrations changes the seawater chemistry; it reduces calcification in phytoplankton, macroalgae and many zoological taxa and enhances UV-induced damage. Ocean warming results in changing species composition and favors blooms of toxic prokaryotic and eukaryotic phytoplankton; it moderates UV-induced damage of the photosynthetic apparatus because of higher repair rates. Increasing pollution from crude oil spills, persistent organic pollutants, heavy metal as well as industrial and household wastewaters affect phytoplankton, which is augmented by solar UV radiation. In view of the fact that extensive analyses of the impacts of multiple stressors are scarce, here we review reported findings on the impacts of anthropogenic stressors on phytoplankton with an emphasis on their interactive effects and a prospect for future studies.

Oxidative environment and redox homeostasis in plants: dissecting out significant contribution of major cellular organelles

Abstract: Plant cells are often exposed to oxidative cellular environments which result in the generation of toxic reactive oxygen species (ROS). In order to detoxify the harmful ROS, plants have evolved various strategies including their scavenging and antioxidant machinery. Plant cells contain many enzymatic and non-enzymatic antioxidants which aid in removing the toxic oxygen molecules. Various antioxidant molecules localized within different cellular compartments play crucial role(s) during this process, which includes both redox-signalling and redox-homeostasis. The present review gives an overview of cellular oxidative environment, redox signalling operative within a cell and contributions of major cellular organelles towards maintaining the redox homeostasis. Additionally, the importance of various antioxidant enzymes working in an orchestrated and coordinated manner within a cell, to protect it from stress injury has been presented. We also present the state-of-the-art where transgenic approach has been used to improve stress tolerance in model and crop species by engineering one or more than one of these components of the ROS scavenging machinery.

Oxidative stress homeostasis in grapevine (Vitis vinifera L.)

Abstract: Plants can maintain growth and reproductive success by sensing changes in the environment and reacting through mechanisms at molecular, cellular, physiological and developmental levels. Each stress condition prompts a unique response although some overlap between the reactions to abiotic stress (drought, heat, cold, salt or high light) and to biotic stress (pathogens) does occur. A common feature in the response to all stresses is the onset of oxidative stress, through the production of reactive oxygen species (ROS). As hydrogen peroxide and superoxide are involved in stress signaling, a tight control in ROS homeostasis requires a delicate balance of systems involved in their generation and degradation. If the plant lacks the capacity to generate scavenging potential, this can ultimately lead to death. In grapevine, antioxidant homeostasis can be considered at whole plant levels and during the development cycle. The most striking example lies in berries and their derivatives, such as wine, with nutraceutical properties associated with their antioxidant capacity. Antioxidant homeostasis is tightly regulated in leaves, assuring a positive balance between photosynthesis and respiration, explaining the tolerance of many grapevine varieties to extreme environments. In this review we will focus on antioxidant metabolites, antioxidant enzymes, transcriptional regulation and cross-talk with hormones prompted by abiotic stress conditions. We will also discuss three situations that require specific homeostasis balance: biotic stress, the oxidative burst in berries at veraison and in vitro systems. The genetic plasticity of the antioxidant homeostasis response put in evidence by the different levels of tolerance to stress presented by grapevine varieties will be addressed. The gathered information is relevant to foster varietal adaptation to impending climate changes, to assist breeders in choosing the more adapted varieties and to suitable viticulture practices.

Combining system dynamics and agent-based modeling to analyze social-ecological interactions—an example from modeling restoration of a shallow lake

Abstract: Modeling social-ecological interactions between humans and ecosystems to analyze their implications for sustainable management of social-ecological systems (SES) has multiple challenges. When integrating social and ecological dynamics, which are often studied separately, one has to deal with different modeling paradigms, levels of analysis, temporal and spatial scales and data availabilities in the social and ecological domains. A major challenge, for instance, is linking the emergent patterns from individual micro-level human decisions to system level processes such as reinforcing feedbacks determining the state of the ecosystem. We propose building a hybrid model that combines a system dynamics with an agent-based approach to address some of these challenges. In particular, we present a procedure for model development and analysis that successively builds up complexity and understanding of model dynamics, particular with respect to feedbacks between the social and ecological system components. The proposed steps allow for a systematic increase of the coupling between the submodels and building confidence in the model before deploying it to study the coupled dynamics. The procedure consists of steps for i) specifying the characteristics of the link between the social and ecological systems, ii) validating the decoupled submodels, iii) doing sensitivity analysis of the decoupled submodels with respect to the drivers from the respective other subsystem and, finally iii) analyzing the coupled model. We illustrate the procedure and discuss opportunities and limitations of hybrid models against the background of an archetypical SES case study, namely the restoration of a turbid lake. Our approach exemplifies how a hybrid model is used to unpack SES complexity and analyze interactions between ecological dynamics and micro-level human actions. We discuss the benefits and challenges of combining a system dynamics models as an aggregated view with an agent-based model as a disaggregated view to improve social-ecological system understanding.

Weather types across the Maritime Continent: from the diurnal cycle to interannual variations

Abstract: Six weather types (WTs) are computed across the Maritime Continent during austral summer (September--April) using cluster analysis of unfiltered, daily, low-level winds at 850 hPa, by a k-means algorithm. This approach is shown to provide a unified view of the interactions across scales, from island-scale diurnal circulations to large-scale interannual ones. The WTs are interpreted either as snapshots of the intraseasonal Madden-Julian Oscillation (MJO); or as seasonal features, such as the transition between boreal- and austral-summer monsoons; or as slow variations associated with the El Ni\o--Southern Oscillation (ENSO). Scale interactions are analyzed in terms of the different phenomena that modulate regional-scale wind speed and direction, or the diurnal-cycle strength of rainfall. Decomposing atmospheric anomalies, relative to the mean annual cycle, into interannual and sub-seasonal components yields similar WT structures on both of these time scales for most of the WTs (4 out of 6). This result suggests that slow (viz. ENSO) and fast (viz. MJO) oscillatory variations superimposed on the mean annual cycle modulate the occurrence rate of WTs, without modifying radically their mean patterns. The latter pattern invariance holds especially true for MJO-type, propagating variations, while the quasi-stationary, planetary-scale ENSO variations have more impact on WT structure. These findings are interpreted with the help of dynamical systems theory. Interannual modulation of WT frequency is strongest for the ``transitional" WTs between the boreal- and austral-summer monsoons, as well as for the ``quiescent" WT, for which low-level winds are reduced over the whole of monsoonal Indonesia. The WT that characterizes NW monsoon surges, and peaks during the austral-summer monsoon in January-February, does not appear to be strongly modulated at the interannual time scale. The diurnal cycle is shown to play an important role in determining the rainfall over islands.

Strategic framework to achieve carbon-efficient construction and maintenance of railway infrastructure systems

Abstract: Sakdirat Kaewunruen*, Joseph M. Sussman and Herbert H. Einstein 1 Birmingham Centre for Railway Research and Education, School of Civil Engineering, University of Birmingham, Birmingham, UK 2 High Speed Rail Research Group, Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA 3 Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA *Correspondence: sakdirat@hotmail.com; s.kaewunruen@bham.ac.uk

Air quality forecasting system for Southeastern Brazil

Abstract: Southeastern Brazil, the most populous and developed region of the country, faces various environmental problems associated with the growth of its population in urban areas. It is the most industrialized area in the country, comprising the metropolitan areas of Sao Paulo, Rio de Janeiro, Belo Horizonte, and other major cities. Air quality is a major concern, because the reported concentrations of certain regulated pollutants, typically ozone and fine particulate, have exceeded national standards. Due to the difficulty in taking measurements over many different areas, air quality modeling is a useful tool to estimate air pollutant concentrations. For southeastern Brazil, air quality modeling has been performed mostly with the Brazilian Regional Atmospheric Modeling System with Simplified Photochemical Module and the Weather Research and Forecast with Chemistry models. One of the main objectives was to study the evolution of air quality associated with improved vehicle emission factors in urban areas, the impact of climate change on air quality, and the relationship between pollutant concentrations and health. Knowledge of mobile source emission factors has been continuously expanded by in-tunnel measurements and dynamometer protocols, which provide accurate data as inputs to photochemical air quality models. The spatial distribution of the mobile source emissions was constructed based on open access data related to the streets and traffic distribution. The mobile emission module was combined to the chemistry modeling and this implementation can be an example to be applied to other places that do not have a spatial distribution of this kind of source. Forecasts of pollutant concentrations can inform public policies, including those addressing the effects of pollutants on health of the general population, and studies of the impacts of using different fuels and implementation of emissions regulations programs.

Estrogenic and anti-androgenic endocrine disrupting chemicals and their impact on the male reproductive system

Abstract: Endocrine disrupting chemicals (EDCs) are identified for their ability to perturb the homeostasis of endocrine system and hormonal balance. The male reproductive system is under close control of hormones and each change in their concentration and time of exposition and action can induce a deregulation of its physiology. In this review we summarize the most recent studies on two main categories of EDCs with different action: the estrogenic bisphenol A and alkylphenols and the anti-androgenic phthalates. This review describes the main effects of these substances on male reproductive system.

A hybrid modeling approach to simulating foot-and-mouth disease outbreaks in Australian livestock

Abstract: Foot-and-mouth disease (FMD) is a highly contagious and economically important viral disease of cloven-hoofed animals Australia's freedom from FMD underpins a valuable trade in live animals and animal products An outbreak of FMD would result in the loss of export markets and cause severe disruption to domestic markets The prevention of, and contingency planning for, FMD are of key importance to government, industry, producers and the community The spread and control of FMD is complex and dynamic due to a highly contagious multi-host pathogen operating in a heterogeneous environment across multiple jurisdictions Epidemiological modelling is increasingly being recognized as a valuable tool for investigating the spread of disease under different conditions and the effectiveness of control strategies Models of infectious disease can be broadly classified as: population-based models that are formulated from the top-down and employ population-level relationships to describe individual-level behaviour, individual-based models that are formulated from the bottom-up and aggregate individual-level behaviour to reveal population-level relationships, or hybrid models which combine the two approaches into a single model The Australian Animal Disease Spread (AADIS) hybrid model employs a deterministic equation-based model (EBM) to model within-herd spread of FMD, and a stochastic, spatially-explicit agent-based model (ABM) to model between-herd spread and control The EBM provides concise and computationally efficient predictions of herd prevalence and clinical signs over time The ABM captures the complex, stochastic and heterogeneous environment in which an FMD epidemic operates The AADIS event-driven hybrid EBM/ABM architecture is a flexible, efficient and extensible framework for modelling the spread and control of disease in livestock on a national scale We present an overview of the AADIS hybrid approach and a description of the model's epidemiological capabilities

Salt stress reveals differential antioxidant and energetics responses in glycophyte (Brassica juncea L.) and halophyte (Sesuvium portulacastrum L.)

Abstract: Salt stress, considered as one of the major factors, decreases crop productivity world-wide and hence, investigations are being made to understand the cellular basis of salt tolerance in plants. In our earlier studies, maintenance of redox homeostasis and energetics were found as key determinants of salt tolerance in a halophyte Sesuvium portulacastrum (high salt accumulator). The redox homeostasis is defined as integrated ratio of different redox couples present inside the cell. In recent years, it has also been proposed as general stress response regulator in plants, bacteria as well as animals. In view of this, present study was performed to compare responses of redox state and energetics of S. portulacastrum with a glycophyte Brassica juncea (low salt accumulator). The data revealed activation of antioxidant defense in S. portulacastrum which either avoided or delayed the accumulation of different reactive oxygen species (ROS). In contrast, due to the lack of co-ordination, although the non-enzymatic antioxidants were increased, significant oxidative damage was seen in B. juncea. Further, the decreased NADPH oxidase activity suggested that basal redox signaling was also affected in B. juncea. In order to correlate these changes with chloroplastic and mitochondrial electron transport chain, NADP/NADPH and NAD/NADH ratios were measured. The NADP/NADPH ratio suggested that the process of photosynthesis was minimally affected in S. portulacastrum which might have contributed to its lower level of ROS under salt stress. The comparatively lower NAD/NADH and ATP/ADP ratios in S. portulacastrum as compared to B. juncea indicated the active and better utilization of energy generated to support different processes associated with salt tolerance. Thus, the findings suggest that co-ordinated regulation of antioxidant defense to avoid oxidative damage and proper utilization of energy are the key determinants of salt-tolerance in plants.

Sustainability of arsenic mitigation interventions—an evaluation of different alternative safe drinking water options provided in Matlab, an arsenic hot spot in Bangladesh

Abstract: The wide spread occurrence of geogenic arsenic (As) in Bangladesh groundwater drastically reduced the safe water access across the country. Since its discovery in 1993, different mitigation options tested at household and community scale have resulted in limited success. In an arsenic hotspot of southeastern Bangladesh, 841 arsenic removal filter (ARF), 190 surface water filter membrane, 23 pond sand filter (PSF), 147 rain water harvester (RWH) and 59 As-safe tubewell were distributed among the severely exposed population by AsMat, a Sida supported project. After three-four years of providing these safe water options, this study was carried out during 2010-2011 for performance analysis of these options, in terms of technical viability and effectiveness and thus to evaluate the preference of different options to the end users. Household and community based surveys were done to make an assessment of the current water use pattern as impact of the distributed options, overall condition of the options provided and to identify the reasons why these options are in use and/or abandoned. In total, 284 households were surveyed and information was collected for 23 PSF, 147 RWH and 59 tubewells. None of the filters was found in use. Among other options distributed, 13% of PSF, 40% RWH and 93% of tubewell were found functioning. In all cases, tubewells were found As-safe. About 89% of households are currently using tubewell water which was 58% before. Filter was abandoned for high cost and complicated maintenance. The use of RWH and PSF was not found user friendly and ensuring year round water quality is a big challenge. Arsenic-safe tubewell was found as a widely accepted option mainly because of its easy operation and availability of water, good water quality and negligible maintenance. This study validated tubewell as the most feasible option and holds significance for planning water supply projects, improving mitigation policy as well as developing awareness among users.

The potential of satellite-observed crop phenology to enhance yield gap assessments in smallholder landscapes

Abstract: Many of the undernourished people on the planet obtain their entitlements to food via agricultural-based livelihood strategies, often on underperforming croplands and smallholdings. In this context, expanding cropland extent is not a viable strategy for smallholders to meet their food needs. Therefore, attention must shift to increasing productivity on existing plots and ensuring yield gaps do not widen. Thus, supporting smallholder farmers to sustainably increase the productivity of their lands is one part of a complex solution to realising universal food security. However, the information (e.g. location and causes of cropland underperformance) required to support measures to close yield gaps in smallholder landscapes are often not available. This paper reviews the potential of crop phenology, observed from satellites carrying remote sensing sensors, to fill this information gap. It is suggested that on a theoretical level phenological approaches can reveal greater intra-cropland thematic detail, and increase the accuracy of crop extent maps and crop yield estimates. However, on a practical level the spatial mismatch between the resolution at which crop phenology can be estimated from satellite remote sensing data and the scale of yield variability in smallholder croplands inhibits its use in this context. Similarly, the spatial coverage of remote sensing-derived phenology offers potential for integration with ancillary spatial datasets to identify causes of yield gaps. To reflect the complexity of smallholder cropping systems requires ancillary datasets at fine spatial resolutions which, often, are not available. This further precludes the use of crop phenology in attempts to unpick the causes of yield gaps. Research agendas should focus on generating fine spatial resolution crop phenology, either via data fusion or through new sensors (e.g. Sentinel-2) in smallholder croplands. This has potential to transform the applied use of remote sensing in this context.

Vehicle Emission Factors of Solid Nanoparticles in the Laboratory and on the Road Using Portable Emission Measurement Systems (PEMS)

Abstract: Emission inventories are used to quantify sources and identify trends in the emissions of air pollutants. They use vehicle-specific emission factors that are typically determined in the laboratory, through remote-sensing, vehicle chasing experiments and, more recently, on-board Portable Emission Measurement Systems (PEMS). Although PEMS is widely applied to measure gaseous pollutants, their application to Solid Particle Number (SPN) emissions is new. In this paper, we discuss the current status of determining SPN emission factors both on the chassis dynamometer and on-road using PEMS-SPN. First, we determine the influence of the measurement equipment, ambient temperature, driving style and cycle characteristics, and the extra mass of the PEMS equipment on the SPN emissions. Afterward, we present the SPN emissions under type-approval conditions as well as on the road of two heavy-duty diesel vehicles equipped with Diesel Particulate Filter (DPF) (one Euro VI), two light-duty diesel vehicles equipped with DPF, one light-duty vehicle equipped with a Port Fuel Injection engine (PFI), and seven Gasoline Direct Injection (GDI) passenger cars (two Euro 6). We find that cold-start and strong accelerations tend to substantially increase SPN emissions. The two heavy-duty vehicles showed emissions around 2×10^13 p/km (Euro V truck) and 6×10^10 p/km (Euro VI truck), respectively. One of the DPF-equipped light-duty vehicles showed emissions of 8×10^11 p/km, while the other one had one order of magnitude lower emissions. The PFI car had SPN emissions slightly higher than 1×10^12 p/km. The emissions of GDI cars spanned approximately from 8×10^11 p/km to 8×10^12 p/km. For the cars without DPF, the SPN emissions remained within a factor of two of the laboratory results. This factor was on average around 0.8 for the Euro 6 and 1.6 for the Euro 5 GDIs. The DPF equipped vehicles showed a difference of almost one order of magnitude between laboratory and on-road tests due to the different DPF fill state and passive regeneration during the tests. The findings of this study can (i) help improving the on SPN emissions and (ii) assist policy makers in designing effective test procedures for measuring SPN emissions of vehicles under real-world driving conditions.

Tropical south east Atlantic warm events and associated rainfall anomalies over southern Africa

Abstract: Moisture flux and rainfall anomalies over southern Africa that have occurred during strong warm SST events off the coast of Angola since 1950 are considered. These events typically occur during February-April (FMA), the main rainy season for Angola / northern Namibia. Eleven of these events have occurred in this sixty year period and each experiences increased rainfall somewhere in coastal Angola, and in ten cases, somewhere in northern Namibia. Attention is focussed on the five events with the largest and most widespread positive rainfall anomalies over Africa south of 10oS; namely, 1963, 1986, 2001, 2006, 2011. All of these five events experienced increased moisture flux from the western tropical Indian Ocean, warm SST anomalies also in the south west Indian Ocean, and most also showed increased westerly moisture flux from the tropical south east Atlantic. The events also showed strong weakening of the mid-level anticyclonic conditions that occur over southern Africa during summer. This factor together with the distribution of anomalous uplift through the middle/upper troposphere appeared to match the areas of increased rainfall better than the areas of low level moisture convergence. Reported experiments with an atmospheric GCM forced with idealisations of the observed SST anomalies show rainfall anomalies consistent with the observed patterns.

Challenges for mountain hydrology in the third millennium

Abstract: Mountain hydrology, in particular in the European Alps, has undergone significant changes within the last decades due to climate and land use change as well as altered water consumption patterns. Climate change influences both the characteristics of droughts and floods as well as evapotranspiration, snow-rainfall ratios, snow seasonality and water reserves locked in glaciers. Land use change and altered water use may strongly outweigh these impacts, in particular through industrialization, urbanization and tourism. Extreme hydrological situations such as new floods types have evolved from combined land-use and climate change and new types of water scarcity in association with accelerated and seasonally shifted water abstraction. Related water quality and pollution issues are of growing concern especially in seasonally highly populated areas. Main methodological challenges include keeping pace with recent hydrological change such as altered water inputs, water abstraction and water quality. Emphasis should be put on the significance of small proportional changes within the total water cycle as these may have major impacts on floods, water scarcity and general livelihood. Political challenges are strongest concerning problem reporting, initiation of monitoring programs and data transparency. The general lack of higher altitude hydrological data and experience with new hydrological phenomena will require an analytical approach directed more strongly towards interactions between scientists, stakeholders and decision makers encompassing local stakeholder knowledge and historical evidence. Data and innovative practices need to be exchanged more strongly between alpine regions and between the local and European level. It should be recognized that an alternative water management in mountains is fundamental for the future.

Specificity and Combinatorial Effects of Bacillus Thuringiensis Cry Toxins in the Context of GMO Environmental Risk Assessment

Abstract: Stacked GM crops expressing up to six Cry toxins from Bacillus thuringiensis are today replacing the formerly grown single- transgene GM crop varieties. Stacking of multiple Cry toxins not only increase the environmental load of toxins but also raise the question on how possible interactions of the toxins can be assessed for risk assessment, which is mandatory for GM crops. However, no operational guidelines for a testing strategy or testing procedures exist. From the developers point of view, little data testing for combinatorial effects of Cry toxins is necessary as the range of affected organisms is focused on pest species and no evidence is claimed to exists pointing to combinatorial effects on nontarget organisms. We have examined this rationale critically using information reported in the scientific literature. To do so we address the hypothesis of narrow specificity of Cry toxins subdivided into three underlying different conceptual conditions i) 'efficacy' in target pests as indicator for 'narrow specificity', ii) lack of reported adverse effects of Cry toxins on nontarget organisms, and iii) proposed modes of action of Cry toxins (or the lack thereof) as mechanisms underlying the reported activity/efficacy/specificity of Cry toxins. Complementary to this information we evaluate reports about outcomes of combinatorial effect testing of Cry toxins in the scientific literature and relate those findings to the practice of the environmental risk assessment of Bt-corps in general and of stacked Bt-events in particular.

An objective criterion for determining the South Atlantic Convergence Zone

Abstract: The South Atlantic Convergence Zone (SACZ) is the dominant summertime cloudiness feature of subtropical South America and the western South Atlantic Ocean, having a significant influence on the precipitation regime of southeastern Brazil. This paper proposes an objective criterion based mainly on precipitation, as this variable is easily obtained on general circulation models simulating past, present and future climate. Usually most SACZ studies use emerging long wave radiation as a precipitation proxy. This is enough to describe event position at first, but using precipitation would allow for better quantification, especially for climate studies, where precipitation is indispensable. An assessment was carried out to find out if classical DJF period is ideal for determining the SACZ for the present climate and future scenarios. In general the SACZ event detection criterion showed quite satisfactory results when event dates were previously known. When it was applied to future climate scenario it identified a number of events compatible with the present climate. The SACZ was well defined for both the simulated and observed precipitation data.

Remote sensing time series analysis for crop monitoring with the SPIRITS software: new functionalities and use examples

Abstract: Monitoring crop and natural vegetation conditions is highly relevant, particularly in the food insecure areas of the world Data from remote sensing image time series at high temporal and medium to low spatial resolution can assist this monitoring as they provide key information about vegetation status in near real-time over large areas The Software for the Processing and Interpretation of Remotely sensed Image Time Series (SPIRITS) is a stand-alone flexible analysis environment created to facilitate the processing and analysis of large image time series and ultimately for providing clear information about vegetation status in various graphical formats to crop production analysts and decision makers In this paper we present the latest functional developments of SPIRITS and we illustrate recent applications The main new developments include: HDF5 importer, Image re-projection, additional options for temporal Smoothing and Periodicity conversion, computation of a rainfall-based probability index (Standardized Precipitation Index) for drought detection and extension of the Graph composer functionalities In particular, The examples of operational analyses are taken from several recent agriculture and food security monitoring reports and bulletins We conclude with considerations on future SPIRITS developments also in view of the data processing requirements imposed by the coming generation of remote sensing products at high spatial and temporal resolution, such as those provided by the Sentinel sensors of the European Copernicus programme

Fresh groundwater for Wajir—ex-ante assessment of uncertain benefits for multiple stakeholders in a water supply project in Northern Kenya

Abstract: Decision-making in development rarely considers uncertainty in project benefits and costs and the risk of project failure. Lack of appropriate tools for ex-ante analysis under conditions of data scarcity constrains the ability of decision-makers to anticipate project outcomes. Business analysis techniques can help in such situations, but they have rarely been applied in development contexts. We use the principles of Applied Information Economics to develop a decision model for a water supply intervention. In the proposed Habaswein-Wajir Water Supply Project in Northern Kenya, water is to be extracted from a major aquifer near Habaswein and piped to the city of Wajir. A team of eight experts developed a model including all costs, benefits and risks considered important for project success. After estimation training, these experts expressed their uncertainty for about 100 variables in the model with probability distributions. We used Monte Carlo simulation to project decision outcomes, and Partial Least Squares regression to identify critical uncertainties affecting the decision. The project was found to be risky for most stakeholders, mainly due to the risk of political interference caused by water supply concerns in Habaswein and due to unclear profitability of the water supply business. Uncertainties about how to value decreasing infant mortality and reduction in water-borne disease incidence were also critical. The greatest hydrological risk was salt water intrusion into the aquifer. Careful well design, inclusive project planning and benefit sharing could raise the chance of project success. The analysis improved understanding of the decision by all stakeholders, some of which changed their opinions on the pipeline, requested more measurements, or proposed alternative water supply options. Decision analysis can help clarify decision uncertainties and outcome expectations and thereby improve decision-making processes, especially in data-scarce areas.

The influence of circulation weather patterns at different spatial scales on drought variability in the Iberian Peninsula

Abstract: Europe has suffered several extreme weather events which were responsible for considerable ecological and economic losses in the last few decades. In Southern Europe, droughts are one of the most frequent extreme weather events, causing severe damages and various fatalities. The main goal of this study is to determine the role of Circulation Weather Types (CWT) on spatial and temporal variability of droughts by means the new multi-scalar Standardized Precipitation Evapotranspiration Index (SPEI). This study aims also to identify the main CWTs associated with winter and summer droughts over different regions of Iberian Peninsula. During the period between 1950 and 2012, the most frequent CWTs were found to be the Anticyclonic (A), Cyclonic (C), North (N) and Northeast (NE) types. The trend analysis for winter season shows a clear increase of frequency CWTs associated to dry events (A, East and Southeast) and a decrease of frequency of C and northern types while in summer a clear decrease of NE is observed. The spatial patterns of correlation between SPEI and CWT show large patterns of negative correlations with winter frequencies of A and eastern weather types, while the reverse occurs with C and western types. This feature is highlighted on a regional approach. The NE type presents negative correlations Central, Northwestern and Southwestern regions during winter and positive correlations in Eastern region during summer. In opposition, the West type presents positive correlations in all regions (except Eastern region) during winter and does not present significant correlations during summer. In general, the predominant CWT associated to winter or summer drought conditions differs greatly between regions. The winter droughts are associated mainly with high frequency of E types and low frequency of W types for all areas, while the summer drought in eastern sectors are linked with low frequency of C type, as well as the western regions are related with the N type.

Genome comparison of two Exiguobacterium strains from high altitude andean lakes with different arsenic resistance: identification and 3D modeling of the Acr3 efflux pump

Abstract: Arsenic exists in natural systems in a variety of chemical forms, including inorganic arsenite (As [III]) and arsenate (As [V]). The majority of living organisms have evolved various mechanisms to avoid occurrence of arsenic inside the cell due to its toxicity. Common core genes include a transcriptional repressor ArsR, an arsenate reductase ArsC, and arsenite efflux pumps ArsB and Acr3. To understand arsenic resistance we have performed arsenic tolerance studies, genomic and bioinformatic analysis of two Exiguobacterium strains, S17 and N139, from the high-altitude Andean Lakes. In these environments high concentrations of arsenic were described in the water due to a natural geochemical phenomenon, therefore, these strains represent an attractive model system for the study of environmental stress and can be readily cultivated. Our experiments show that S17 has a greater tolerance to arsenite (10nM) than N139, but similar growth in arsenate (150nM). We sequenced the genome of the two Exiguobacterium and identified an acr3 gene in S17 as the only difference between both species regarding known arsenic resistance genes. To further understand the Acr3 we modeled the 3D structure and identified the location of relevant residues of this protein. Our model is in agreement with previous experiments and allowed us to identify a region where a relevant cysteine lies. This Acr3 membrane efflux pump, present only in S17, may explain its increased tolerance to As(III) and is the first Acr3-family protein described in Exiguobacterium genus.