Metal levels in sugar cane (Saccharum spp.) samples from an area under the influence of a municipal landfill and a medical waste treatment system in Brazil

In July 2003, duplicated samples of roots, stems and leaves of sugar cane (Saccharum spp.) were collected in 25 points of an area under direct influence of the municipal landfill site (MLS) and medical waste treatment system (MWTS) of Ribeirao Preto, S?o Paulo, Brazil. Cadmium (Cd), chromium (Cr), copper (Cu), mercury (Hg), manganese (Mn), lead (Pb) and zinc (Zn) were determined by atomic absorption spectrophotometry. The following concentrations (mg/kg) were found in roots: Cd, 0.22+/-0.12; Cr, 64.3+/-48.7; Cu, 140.6+/-27.7; Hg, 0.04+/-0.02; Mn, 561.6+/-283.3; Pb, 7.9+/-2.1 and Zn, 177.4+/-64.9. For some metals, these levels are higher than the concentrations previously reported for different plants, reaching, in some cases, values that might be considered toxic for vegetables. Metal levels in stems were 80-90% of those found in roots, while the concentrations detected in leaves were significantly lower than those in roots. The present results suggest that MLS and MWTS activities might have been increasing metal concentrations in edible tissues of sugar cane grown in the area under their influence. Moreover, the traditional agricultural practices in the production of sugar cane could be also another determinant factor to reach the current metal levels. The results of this study indicate that sugar cane is a crop that is able to grow in areas where metals in soils are accumulated.     

Multivariate curve resolution of multidimensional excitation-emission quenching matrices of a Laurentian soil fulvic acid

Fluorescence excitation–emission matrices (EEM) of aqueous solutions of Laurentian soil fulvic acid (LFA) at three concentrations (50, 75 and 100 mg/l) were obtained at two pH values (pH = 4.0 and 6.0) and as function of the Cu(II) ion concentration. The presence of Cu(II) ion provokes quenching of the intrinsic LFA fluorescence due to complex formation. Multivariate curve resolution (MCR-ALS) was used to successfully decompose single EEM into excitation and emission spectra for the detected components. Moreover, multidimensional (up to six dimensions) data matrices were generated by adding EEM collected as function of the LFA and Cu(II) concentrations and pH. MCR-ALS was able to resolve the excitation and emission spectra from these multidimensional data matrices given further information about the spectral variation profiles induced by the experimental factors. Conditional stability constants (log K_LFACu) were calculated from the quenching profiles observed as function of the Cu(II) concentration, as well as, their trends as function of pH and LFA concentration were obtained – average (and standard deviation) of log K_LFACu = 4.6 ± 0.2. This EEM/MCR-ALS methodology constitutes a new tool for the study of natural organic matter under varying experimental conditions that characterize natural environmental systems.     

A spatial scan statistic for zero-inflated Poisson process

The scan statistic is widely used in spatial cluster detection applications of inhomogeneous Poisson processes. However, real data may present substantial departure from the underlying Poisson process. One of the possible departures has to do with zero excess. Some studies point out that when applied to data with excess zeros, the spatial scan statistic may produce biased inferences. In this work, we develop a closed-form scan statistic for cluster detection of spatial zero-inflated count data. We apply our methodology to simulated and real data. Our simulations revealed that the Scan-Poisson statistic steadily deteriorates as the number of zeros increases, producing biased inferences. On the other hand, our proposed Scan-ZIP and Scan-ZIP+EM statistics are, most of the time, either superior or comparable to the Scan-Poisson statistic.     

Differences in diet composition and foraging patterns between sexes of the Magellanic penguin (Spheniscus magellanicus) during the non-breeding period as revealed by δ13C and δ15N values in feathers and bone

In diving seabirds, sexual dimorphism in size often results in sex-related differences of foraging patterns. Previous research on Magellanic penguins, conducted during the breeding season, failed to reveal consistent differences between the sexes on foraging behavior, despite sexual dimorphism. In this paper, we tested the hypothesis that male and female Magellanic penguins differ in diet and foraging patterns during the non-breeding period when the constraints imposed by chick rearing activities vanish. We used stable isotope ratios of carbon and nitrogen in feather and bone to characterize the diet and foraging patterns of male and female penguins in the South Atlantic at the beginning of the 2009–2010 and 2010–2011 post-breeding seasons (feathers) and over several consecutive breeding and migratory seasons (bone). The mean δ¹³C and δ¹⁵N values of feathers showed no differences between the sexes in any of the three regions considered or in the diet composition between the sexes from identical breeding regions; however, Bayesian ellipses showed a higher isotopic niche width in males at the beginning of the post-breeding season. Stable isotope ratios in bone revealed the enrichment of males with δ¹³C compared with females across the three regions considered. Furthermore, the Bayesian ellipses were larger for males and encompassed those of females in two of the three regions analyzed. These results suggest a differential use of winter resources between the sexes, with males typically showing a larger diversity of foraging/migratory strategies. The results also show that dietary differences between male and female Magellanic penguins may occur once the constraints imposed by chick rearing activities cease at the beginning of the post-breeding season.     

Geochemistry,mineralogy, solid-phase fractionation and oral bioaccessibility of lead in urban soils of Lisbon

An urban survey of Lisbon, the largest city in Portugal, was carried out to investigate its environmental burden, emphasizing metallic elements and their public health impacts. This paper examines the geochemistry of lead (Pb) and its influence on human health data. A total of 51 soil samples were collected from urban recreational areas used by children to play outdoors. The semi-quantitative analysis of Pb was carried out by inductively coupled plasma mass spectrometry after an acid digestion. X-ray diffraction was used to characterize the soil mineralogy. The solid-phase distribution of Pb in the urban soils was investigated on a subset of 7 soils, out of a total of 51 samples, using a non-specific sequential extraction method coupled with chemometric analysis. Oral bioaccessibility measurements were obtained using the Unified BARGE Method developed by the Bioaccessibility Research Group of Europe. The objectives of the study are as follows: (1) investigation of Pb solid-phase distribution; (2) interpretation of Pb oral bioaccessibility measurements; (3) integration of metal geochemistry with human health data; and (4) understanding the influence of geochemistry and mineralogy on oral bioaccessibility. The results show that the bioaccessible fraction of Pb is lower when major metal fractions are associated with less soluble soil phases such as Fe oxyhydroxides, and more increased when the metal is in the highly soluble carbonate phase. However, there is some evidence that the proportion of carbonates in the soil environment is also a key control over the oral bioaccessibility of Pb, irrespective of its solid-phase fractionation.     

Nation‐building policies in Timor‐Leste: disaster risk reduction,including climate change adaptation

Few studies have explored the relationships between nation‐building, disaster risk reduction and climate change adaptation. Focusing on small island developing states, this paper examines nation‐building in Timor‐Leste, a small island developing state that recently achieved independence. Nation‐building in Timor‐Leste is explored in the context of disaster risk reduction, which necessarily includes climate change adaptation. The study presents a synopsis of Timor‐Leste's history and its nation‐building efforts as well as an overview of the state of knowledge of disaster risk reduction including climate change adaptation. It also offers an analysis of significant gaps and challenges in terms of vertical and horizontal governance, large donor presence, data availability and the integration of disaster risk reduction and climate change adaptation for nation‐building in Timor‐Leste. Relevant and applicable lessons are provided from other small island developing states to assist Timor‐Leste in identifying its own trajectory out of underdevelopment while it builds on existing strengths.     

Spatio-temporal variations of fluorescence properties of dissolved organic matter along the River Têt (Pyrénées-Orientales,France)

Fluorescence excitation-emission matrices showed the spectral signature of dissolved organic matter (DOM) downstream in the River Têt at all seasons corresponding to humic substances with maximum fluorescence emission λem=420–460 nm for excitations of λex=340–360 nm and the occasional presence of tryptophan, tracer of anthropogenic pressure, spectroscopically identified by λex/λem=310/350 nm. A factorial discriminant analysis, performed using the parameters selected (λex/λem pairs of wavelength), succeeded in a better discrimination of seasons than stations, and clearly showed the presence of two fluorophores. Fluorophore 1, with two absorption bands: λex=260–320 nm and 330–390 nm for λem=440–500 nm, and Fluorophore 2, with one absorption band: λex=300–360 nm for λem=410 nm, which are attributed to humic acid (HA) and fulvic acid (FA), respectively. Variations of DOM relative contents downstream in the River Têt, according to seasons and stations, showed high amounts of DOM (pedogenic character) along the river in the humid period, with the highest value obtained in the mountain section. In contrast, in summer, the DOM contents were low (aquagenic character). Moreover, DOM presents a relatively constant composition with a percentage of FA ranging from 40% at the mountain station to 48% at the mouth river, whatever the season.     

Identification of Sudan III-(deoxy)-guanosine adducts formed in situ in a reaction with no catalyst

Incubation of guanosine and Sudan III induces the formation of a stable adduct, which may be identified using a spectrophotometric technique and mass spectroscopy. The high nucleophilicity of the C⁸ position and its proximity to N⁷ makes the site susceptible to a nucleophilic attack, which explains the S_N2 reaction detected between guanosine and Sudan III dye. In addition, direct interaction of Sudan III with calf thymus DNA was monitored using a simple spectrophotometric technique. The results presented indicate that a simple modification of the chemical structure of Sudan I (monoazo dye) to Sudan III (diazo dye) markedly alters reactivity towards nitrogenous DNA bases.     

Melanin-based colour polymorphism signals aggressive personality in nest and territory defence in the tawny owl (Strix aluco)

Nest and territory defence are risky and potentially dangerous behaviours. If the resolution of life history trade-offs differs between individuals, the level of defence may also vary among individuals. Because melanin-based colour traits can be associated with life history strategies, differently coloured individuals may display different nest and territory defence strategies. We investigated this issue in the colour polymorphic tawny owl (Strix aluco) for which plumage varies from dark to light reddish melanic. Accordingly, we found that (1) our presence induced a greater response (flying around) from dark-coloured than light-coloured females and (2) dark reddish males suffered lower nest predation rates than light-coloured males. In experimentally enlarged broods, the probability that females reacted after we played back the hoot calls of a stranger male was higher if these females were lighter reddish; the opposite pattern was found in experimentally reduced broods with dark parents being more reactive than light parents. Finally, darker females alarmed more frequently when paired with a light than with a dark male, suggesting that partners adjust their behaviour to each other. We also tested whether colouration is used as a signal by conspecifics to adjust the level of their defensive behaviour. Accordingly, breeding females responded more vigorously to a dark than a light reddish stuffed tawny owl placed beside their nest. We conclude that melanin-based colouration is a signal of alternative nest and territory defence behaviour that depends on ecological factors.     

Phytoplankton communities in aquaculture system (integration of shrimp and seaweed)

ABSTRACT

Knowledge about phytoplankton communities is important for aquaculture due to their influence on environmental variables. The goal of the study was to evaluate the ecological effect of seaweed Gracilaria birdiae at three different densities: 2.5 (LG2.5); 5.0 (LG5.0) and 7.5?kg m^?3 (LG7.5), on water quality variables and the phytoplankton communities in integrated aquaculture systems (shrimp and seaweed) with a control (without seaweed) (LB) using biofloc technology. Settleable and total suspended solids were significantly correlated with the phytoplankton groups. In addition, orthophosphate was the main variable controlling phytoplankton growth and gross primary production. No significant differences were identified among the treatments in terms of the phytoplankton assemblages (p?>?0.05) but differences were found between the communities (ANOSIM, R global?=?0.873) in relation to the days of the experiment. However, the LG2.5 treatment had higher diversity and lower species dominance, as well as higher productivity and final shrimp weight. The results indicate that seaweed inhibit phytoplankton growth, mainly of toxic species. They suggest that phytoplankton composition in integrated aquaculture systems in the presence of seaweed at a density of 2.5?kg m^?3 is more diversified and provides better water quality and shrimp performance by inhibiting the abundance of harmful species.