Simulation-based optimization of in–stream structures design: bendway weirs

Bendway weirs are one of the most practical in–stream rock structures utilized to protect the outer bend of meandering streams and rivers from erosion. We present development of a simulation-based paradigm for effective design of bendway weir structures to enhance meandering stream bank stability and control lateral migration. To do so, we employ the St. Anthony Falls Laboratory Virtual StreamLab (VSL3D) code to elucidate the flow and sediment transport phenomena induced by interaction of flow, mobile bed, and in–stream structures in large rivers under prototype conditions. We carried out numerous numerical experiments to systematically simulate various arrangements of bendway weir in two river test-beds and gaining insights into the physical mechanisms via which such bendway weirs modify turbulent flow, sediment transport and scour processes. The so-gained physical insights are then taken into account to develop a set of practical physics-based design criteria for optimal placement of bendway weirs in large rivers.     

A note on the thyroid function of the pregnant females in the USA: data from NHANES 1999–2002 and 2007–2012

Thyroid dysfunction during pregnancy has been shown to be associated with adverse pregnancy outcomes. Consequently, this study was undertaken to assess the thyroid health of the pregnant females in the United States. Publically available data from National Health and Nutrition Examination Survey for the cycles 1999–2002 and 2007–2012 were analyzed for this purpose. Over 22% (SE: 5.7%) of the pregnant females based on the unweighted data in their first trimester had higher than the recommended levels of thyroid-stimulating hormone (TSH) or 2.5 mIU/L. Free triiodothyronine (FT3) and free thyroxine (FT4) levels decreased over pregnancy trimesters. Based on unweighted data, about 6% (SE: 2.6%) pregnant females were positive for thyroglobulin antibodies and 34.9% (SE: 5.2%) pregnant females were positive for thyroid peroxidase antibodies. Over 55% (SE: 3.5%) pregnant females based on the unweighted data were iodine deficient. As many as 41% (SE: 3%) first trimester pregnant females having TSH > 2.5 mIU/L is of concern. Future research should concentrate on developing educational and other materials that can advise pregnant females during their prenatal care and other appointments about the adverse effects of high TSH levels and what they can do to keep their TSH levels within the recommended levels.     

Behavioral type–environment correlations in the field: a study of three-spined stickleback

Behavioral type–environment correlations occur when specific behavioral types of individuals are more common in certain environments. Behavioral type–environment correlations can be generated by several different mechanisms that are probably very common such as niche construction and phenotypic plasticity. Moreover, behavioral type–environment correlations have important ecological and evolutionary implications. However, few studies have examined behavioral type–environment correlations in natural populations. In this study, we asked whether some behavioral types of three-spined stickleback were more likely to occur in certain social environments (alone or in a shoal with other stickleback) or in certain microhabitats in a river (in the open or under cover). We found that individuals that were in shoals with other stickleback at the time of collection from the field emerged from a refuge more quickly compared to individuals that were found alone. In addition, fish that were alone in an open microhabitat explored more of a pool compared to fish that were alone in cover, but this difference did not occur among fish that were in shoals at the time of collection. Subsequent analyses of gut contents suggested that differences in microhabitat use were consistent over time. Our study provides some of the first evidence for behavioral type–environment correlations in a natural population of non-human animals.     

National water footprint in an input–output framework—A case study of China 2002

Water footprint is an indicator showing the consumption impact on environment with water equivalent, which allows a detailed quantification of water use directly and indirectly in sectors for the domestic and abroad final consumption. This paper presents a framework of calculating national water footprint (NWF) with input–output method on China 2002. The results indicated that the NWF of China was 381 m³/cap yr in 2002. A new indicator termed as national water footprint intensity (NWFI) is also derived from NWF to evaluate the water consumption intensities of different sectors. Then the evaluation of virtual water trade in sectors is followed, the results of which give a detailed quantification of net virtual water import of sectors, verifying that China is a net virtual water exporter concerning the whole national sectors, which is different from the previous studies. Finally, it is suggested that the sectors with high NWFI and volume of net virtual water export should be regarded as the priority of Chinese water-saving strategy.     

Measurement of metal bioaccessibility in vegetables to improve human exposure assessments: field study of soil–plant–atmosphere transfers in urban areas,South China

The quality of cultivated consumed vegetables in relation to environmental pollution is a crucial issue for urban and peri-urban areas, which host the majority of people at the global scale. In order to evaluate the fate of metals in urban soil–plant–atmosphere systems and their consequences on human exposure, a field study was conducted at two different sites near a waste incinerator (site A) and a highway (site B). Metal concentrations were measured in the soil, settled atmospheric particulate matter (PM) and vegetables. A risk assessment was performed using both total and bioaccessible metal concentrations in vegetables. Total metal concentrations in PM were (mg kg^?1): (site A) 417 Cr, 354 Cu, 931 Zn, 6.3 Cd and 168 Pb; (site B) 145 Cr, 444 Cu, 3289 Zn, 2.9 Cd and 396 Pb. Several total soil Cd and Pb concentrations exceeded China’s Environmental Quality Standards. At both sites, there was significant metal enrichment from the atmosphere to the leafy vegetables (correlation between Pb concentrations in PM and leaves: r = 0.52, p < 0.05) which depended on the plant species. Total Cr, Cd and Pb concentrations in vegetables were therefore above or just under the maximum limit levels for foodstuffs according to Chinese and European Commission regulations. High metal bioaccessibility in the vegetables (60–79 %, with maximum value for Cd) was also observed. The bioaccessible hazard index was only above 1 for site B, due to moderate Pb and Cd pollution from the highway. In contrast, site A was considered as relatively safe for urban agriculture.     

Rose Bengal‐sensitized photooxygenation of chlorohydroxyaromatic contaminants in water: A kinetic study

A kinetic study of the RB‐sensitized photooxygenation of a series of chlorohydroxyaromatic (ClArOH) water contaminants (phenolic and dihydroxybenzene derivatives) has been carried out. In addition, an exhaustive study on the possible interactions of RB electronically excited triplet and singlet states with ClArOH was also developed. The determination of relative rates of oxygen uptake upon sensitized irradiation, employing auxiliar selective quenchers of oxygen active species, indicate the contribution of both singlet molecular oxygen (ca. 71%) and Superoxide ion (ca. 26%) as the reactive pathways for ClArOH degradation. The substitution by chlorine atoms in position meta greatly decrease the photooxygenation rate of the phenolic derivatives. For the dihydroxybenzene series, increase in nuclear chlorination parallels a decrease in the photodegradation rate.

Outdoors sensitized solar irradiation experiments on different ClArOH mixtures leads to measurable levels of oxygen after a few minutes exposure. From the environmental point of view, and ruling out the possibility of direct‐irradiation photoreactions, sensitized photooxygenation appears as an alternative pathway for ClArOH degradation, in competence with other naturally‐occurring photoprocesses involving reactive transient species.     

Variations in δ13C of water–soluble leaf and phloem organic matter of Platycladus orientalis: influences of photosynthetic and post–photosynthetic fractionation

Analysis of variations in water–soluble organic matter (WSOM) δ¹³C of leaves and phloem can efficiently describe the δ¹³C distributions within plants and identify the temporal variation of δ¹³C. In this study, WSOM δ¹³C values of both leaves and phloem (twig, stem, and root) of Platycladus orientalis were measured during seven sunny days, including 2–hour interval measurements at three days for diel pattern analysis and 6–hour interval measurements at the remaining four days for day–to–day variation analysis. Analysis of WSOM δ¹³C in different plant organs showed that ¹³C was generally depleted from leaves to twigs, then enriched in stems and subsequently depleted in roots. Stems were significantly ¹³C–enriched compared to twigs (p?<?0.05), while δ¹³C differences between stems and other organs and among leaves, twigs and roots were not significant (p?>?0.05). No clear diel patterns in δ¹³C of leaves and phloem were found. Daily average δ¹³C values indicated that all plant organs had more positive values on sunny days during the dry season than during the wet season. Both photosynthetic and post–photosynthetic fractionation influence variations in WSOM δ¹³C. These results have implications for research on plant physiology and plant water use.     

North–south trade in reusable goods: Green design meets illegal shipments of waste

In a stylized model of international trade, firms in the North indirectly export second-hand products to a representative firm in the South to be reused as intermediate goods, with potential trade gains. The level of reusability of waste products – or green design – is a crucial choice variable in the North. This is because, in the presence of imperfect international monitoring, non-reusable waste can be illegally mixed with reusable waste. I explore the driving forces for illegal waste movement, with a particular focus on local waste regulations such as the EU׳s Directive on Waste Electrical and Electronic Equipment. Under mild conditions, it is shown that increasingly stringent regulations in the North can induce Northern firms to reduce product reusability. Consequently, the flow of non-reusable waste to the South increases, magnifying the pollution haven effect.     

Fate of organo‐heavy metal complexes of sludges from domestic wastes in soils: A simplified modelization

Simplified models provided information on the binding ability of organic acids with trace elements, the distribution of the formed organo‐heavy metal complexes at different pH, and the biological stability (biodegradation ability) of these complexes.     

Selenium status of children in Kashin–Beck disease endemic areas in Shaanxi,China: assessment with mercury

Environmental Geochemistry and Health - The causes of Kashin–Beck disease (KBD) in children are multifactorial, and particular consideration has been given to childhood selenium (Se)...     

Mediating male–male interactions: the role of the UV blue crest coloration in blue tits

Badges of status, usually color patches, are hypothesized to serve as important signals within natural populations by communicating an individual’s fighting ability or aggressiveness before an interaction ever takes place. These signals, which may evolve via sexual and/or social selection, mediate intra-specific competition by influencing the outcome or escalation of contests between individuals. The last 10 years saw the rise of interest in the role of ultraviolet (UV)-based coloration in intra-sexual communication. However, the rare experimental studies that tested this hypothesis found opposite results, which may originate from the different methodological procedures used to assess the badge of status theory. We present here the results of an experiment testing whether male blue tits (Cyanistes caeruleus) respond differently to unfamiliar conspecifics presenting contrasted UV crest coloration. In an aviary, we simultaneously presented two caged blue tits with enhanced (UV+) or reduced (UV−) crest coloration to a focal bird. We found that focal males acted more aggressively towards the UV− males than UV+ males. In addition, focal males fed more often close to males that were similar in brightness or duller than themselves. We conclude that, in blue tits, UV blue crest coloration affects both social and aggressive responses towards unfamiliar individuals, and thus it has some properties of a badge of status.     

Parcelization in rural agricultural and forested landscapes in Wisconsin, 1972–2007: evaluating multiple dimensions of human decision-making over time

Many land-use change studies have relied on geographical explanatory factors. Unfortunately, they are but a single perspective in the multidimensional process of human decision-making. This project was designed to model the social, economic, geographic, and regulatory factors at the most appropriate unit of analysis, the landowner. By examining parcelization, a window is opened into the antecedent event of land-use change. A logistic regression model determined the likelihood a tax parcel would split in three time periods between 1953 and 2007. Geographic variables showed expected relationships to a parcelization event, while economic and regulatory variables illustrated some unexpected relationships. Social variables demonstrated scale issues that challenged their efficacy. A temporal analysis showed that historic parcelization was explained more robustly than more contemporary parcelization. The results could indicate that contemporary parcelization is driven by new and more complex factors not yet represented in similar models.     

Species distribution modelling: Does one size fit all? A phytogeographic analysis of Salix in Ontario

Empirical models for predicting the distribution of organisms from environmental data have often focused on principles of ecological niche theory. However, even at large scales, there is little agreement over how to represent the dimensions of a species’ niche. The performance of such models is greatly affected by the nature of species distributional and environmental data. Regional scale distribution models were developed for 30 willow species in Ontario to examine (i) the predictive ability of logistic regression analysis, and (ii) the effects of using different distributional and environmental data sets. Two original measures of model accuracy and over-prediction were employed and evaluated using independent data. Models based on unique combinations of monthly climate data predicted distributions most accurately for all species. Models based on a fixed set of variables, while generating the highest average probabilities of occurrence for certain species with limited ranges, resulted in the greatest under- and over-estimates of willow distributions. Comparisons of models demonstrated climatic patterns among willows of differing habit and habitat. The distribution of dwarf willow species, present only in the Ontario arctic, followed gradients of summer maximum temperatures. The distribution of the tree species in the southerly portions of the province followed gradients of fall and winter minimum temperatures. Regardless of distributional and environmental data input, no algorithm maximized model performance for all species. Individual species models require individual approaches; i.e., the variable selection technique, the set of environmental factors used as predictors, and the nature of species distributional data must be carefully matched to the intended application. An understanding of evolutionary processes enhances the meaningful interpretation of individual species models. Unless sampling bias and species prevalence can be accounted for, models based on collection point data are best used to guide field surveys. While inferred range data may be better suited to determine potential ecological niches, overestimation of species prevalence and environmental tolerance must be recognized. A combination of available distributional data types is recommended to best determine species niches, an important step in developing conservation strategies.     

A test of the mismatch hypothesis: How is timing of reproduction related to food abundance in an aerial insectivore?

In seasonal environments, vertebrates are generally thought to time their reproduction so offspring are raised during the peak of food abundance. The mismatch hypothesis predicts that reproductive success is maximized when animals synchronize their reproduction with the food supply. Understanding the mechanisms influencing the timing of reproduction has taken on new urgency as climate change is altering environmental conditions during reproduction, and there is concern that species will not be able to synchronize their reproduction with changing food supplies. Using data from five sites over 24 years (37 site-years), we tested the assumptions of the mismatch hypothesis in the Tree Swallow (Tachycineta bicolor), a widespread aerial insectivore, whose timing of egg-laying has shifted earlier by nine days since the 1950s. Contrary to the mismatch hypothesis, the start of egg-laying was strongly related to food abundance (flying insect biomass) during the laying period and not to timing of the seasonal peak in food supply. In fact, food abundance generally continued to increase throughout the breeding season, and there was no evidence of selection based on the mistiming of laying with the seasonal peak of food abundance. In contrast, there was selection for laying earlier, because birds that lay earlier generally have larger clutches and fledge more young. Overall, initial reproductive decisions in this insectivore appear to be based on the food supply during egg formation and not the nestling period. Thus, the mismatch hypothesis may not apply in environments with relatively constant or abundant food throughout the breeding season. Although climate change is often associated with earlier reproduction, our results caution that it is not necessarily driven by selection for synchronized reproduction.     

Sensitivity of a coupled physical–biological model to turbulence: high-frequency simulations in a northern Adriatic station

This paper investigates the impacts of different turbulence models on the biological state at an ocean station in the northern Adriatic sea, named S3, comparing them with other uncertainties inherent to coupled physical–biological simulations. The numerical tool is a 1-D model resulting from the coupling of two advanced numerical models. The hydrodynamic part is modelled using the General Ocean Turbulence Model (www.gotm.net), in a version adopting state-of-the-art second-moment Turbulence Closure Models (TCMs). Marine biogeochemistry is parameterized with the Biogeochemical Flux Model (http://www.bo.ingv.it/bfm), which is a direct descendant of ERSEM (European Regional Sea Ecosystem Model). Results, obtained by forcing the model with hourly wind and solar radiation data and assimilating salinity casts, are compared against monthly observations made at the station during 2000–2001. Provided that modern second-moment TCMs are employed, the comparisons indicate that both the physical and the biological dynamics are relatively insensitive to the choice of the particular scheme adopted, suggesting that TCMs have finally ‘converged’ in recent years. As a further example, the choice of the nutrient boundary conditions has an impact on the system evolution that is more significant than the choice of the specific TCM, therefore representing a possible limitation of the 1-D model applied to stations located in a Region of Freshwater Influence. The 1-D model simulates the onset and intensity of the spring–summer bloom quite well, although the duration of the bloom is not as prolonged as in the data. Since local dynamics appears unable to sustain the bloom conditions well into summer, phytoplankton at the station was most likely influenced by river input or advection processes, an aspect that was not found when the S3 behaviour was adequately modelled using climatological forcings. When the focus is in predicting high-frequency dynamics, it is more likely that lateral advection cannot be neglected. While the physical state can be satisfactorily estimated at these short time scales, the accurate estimation of the biological state in coastal regions still appears as rather elusive.     

Soil surface nitrogen losses from agriculture in India: A regional inventory within agroecological zones (2000–2001)

We present soil surface nitrogen (N) budgets for the agricultural sector of India, calculated as inputs minus outputs over 21 agroecological zones (AEZ), for 2000–2001. Nearly 35.4 Tg N was input from different sources, with output from harvested crops of about 21.2 Tg N. Soil surface N balance for agricultural lands showed a surplus of about 14.4 Tg. Livestock manure constituted 44% of total inputs, followed by 32.5% from inorganic fertilizer, 11.9% from atmospheric deposition and 11.6% from N fixation. Though the N balance was negative in some states, due to aggregation of states in agroecological regions, all regions showed surplus N loads, with a range of about 19–110 kg/ha. The lowest loads were found for AEZ 17 in the Eastern Himalaya, with 19 kg/ha surplus, and the highest surplus N load in AEZ 7 with 111 kg/ha in Deccan plateau and the Eastern Ghats. Temporal trends in fertilizer consumption from 1950–2000 for India suggested a massive increase of ～47-fold, whereas production of major crops, rice, wheat and maize, increased nearly ～4.0-, 10- and 6-fold, respectively. Fertilizer consumption patterns were highly concentrated in Tamilnadu (204.6 kg/ha), Haryana (132.0 kg/ha) and Punjab (148.6 kg/ha). The paper addresses the role of agricultural intensification and its implications for water quality in agroecological regions of India.     

Agro-biodiversity in rice–wheat-based agroecosystems of eastern Uttar Pradesh,India: implications for conservation and sustainable management

In this study, we analysed the indigenous practices of agro-biodiversity, changing patterns of cropping systems and conservation of agriculturally important natural resources of rice–wheat-based agroecosystems. The research was carried out in three villages of Azamgarh district, eastern Uttar Pradesh, India. Participatory approaches and personal interviews were combined to collect the data from 180 farmers. The results indicated that resource-poor (RP) farmers, by applying traditional practices of natural resource conservation, outperform their rich (RR) counterparts in conserving agro-biodiversity. Increase in irrigation facilities, adoption of improved crop varieties, commercialisation of farming and socio-economic changes have threatened the agro-biodiversity and related natural resources of these agroecosystems. For most of the crops, the RP farmers had better production stability as compared to the RR ones because the former tend to apply more sustainable and ecologically sound indigenous practices. A negative growth rate was observed in the area/numbers and production of legumes, livestock, pasture lands and community forestry. Women, who are the local custodians of conserving indigenous biodiversity (uncultivated species) and crop varieties through localised knowledge and sociocultural institutions, had significantly higher knowledge on agro-biodiversity than men. We concluded that integration of farmers’ eco-friendly practices with formal science and policy-making in a participatory mode may enhance sustainability of functions of agroecosystem leading to the strengthening of adaptive practices in changing climate and socio-economic scenario.