Local Perception of Environmental Change in a Semi-Arid Area of Northeast Brazil: A New Approach for the Use of Participatory Methods at the Level of Family Units

The diversity of plant resources in the Brazilian semi-arid region is being compromised by practices related to agriculture, pastures, and forest harvesting, especially in areas containing Caatinga vegetation (xeric shrublands and thorn forests). The impact of these practices constitutes a series of complex factors involving local issues, creating a need for further scientific studies on the social-environmental dynamics of natural resource use. Through participatory methods, the present study analyzed people’s representations about local environmental change processes in the Brazilian semi-arid region, taking into consideration local production systems, natural resources, and their importance. Environmental historical graphs were developed with nine local families to analyze landscape changes with regard to cultivated areas and pastures, and their relationship with the availability of native vegetation. Punctuation exercises were performed to observe the importance of each unit that supplied native and cultivated resources. The availability of native resources in the environment is subject to stability, as observed by a majority of the local families. The role of the production units (crops and pastures) was emphasized by most families in the study, especially because of the need for products for subsistence needs and income generation. The current decline of such practices is a consequence of an exodus of field workers and also relates to the conservation of native species that otherwise would have been deforested in favor of agricultural practices.     

Okadaic acid induces morphological changes, apoptosis and cell cycle alterations in different human cell types

Okadaic acid (OA) is a marine toxin produced by dinoflagellate species which is frequently accumulated in molluscs usual in the human diet. The exact action mechanism of OA has not been described yet and the results of most reported studies are often conflicting. The aim of this work was to evaluate the OA effects on morphology, cell cycle and apoptosis induction by means of light microscopy and flow cytometry, in three different types of human cells (leukocytes, HepG2 cells and SHSY5Y cells). Cells were treated with a range of OA concentrations in the presence and absence of S9 fraction. OA induced morphological changes in all the cell types studied, and cell cycle disruption only in leukocytes and neuronal cells. SHSY5Y cells were the most sensitive to OA assault. Results obtained in the presence and absence of metabolic activation were similar, suggesting that OA acts both directly and indirectly. Furthermore, OA was found to increase the subG(1) region in the flow cytometry cell cycle analysis, suggesting induction of apoptosis. These results were confirmed by the employment of specific methodologies for studying apoptosis such as caspase 3 activation and annexin V staining. Increases in the apoptosis rate were obtained in all the cells treated in the absence of S9 fraction, accompanied by increases in caspase 3 activation, suggesting that apoptosis induced by OA is a caspase 3-dependent process. Nevertheless, in the presence of S9 fraction no apoptosis was detected, indicating a metabolic detoxifying activity, although necrosis was observed in neuroblastoma cells.     

Tracking sewage derived contamination in riverine settings by analysis of synthetic surfactants

A study has been made of the presence and reactivity of the most commonly used surfactants, both anionic (linear alkylbenzene sulfonates, LAS, and alkyl ethoxysulfates, AES) and non-ionic (alcohol polyethoxylates, AEOs, and nonylphenol polyethoxylates, NPEOs), in water and surface sediments from the middle stretch of the Guadalete River in SW Spain (12 stations). Average values were between 0.1 and 3.7 mg kg(-1) in sediment, and between 0.2 and 37 μg L(-1) in water. The sorption of surfactants was dominated by hydrophobic mechanisms, so those homologues having longer alkyl chains (e.g. C(18)AEO) showed higher relative percentages and concentrations in sediments compared with water. Local and sharply higher concentrations of these compounds were observed at three sampling stations (7, 9 and 12), indicating the occurrence of wastewater discharges into the river. By analysing the distributions of different surfactant homologues and their metabolites we were able to distinguish between sewage contamination from sources discharging treated and untreated wastewaters. Upstream (stations 1-2), LAS concentrations were below 30 μg L(-1) and the composition of their degradation intermediates (sulfophenyl carboxylic acids, SPCs) (160 μg L(-1)) was dominated by short-chain homologues (C(6)-C(9)SPCs), indicating that the degradation of this surfactant is at an advanced stage. The highest concentration (487 μg L(-1)) of SPCs was detected near the effluent outlet of a sewage treatment plant (STP) (station 12). Sampling stations (7 and 9) affected by untreated wastewater discharges were the only ones showing the presence of the most reactive and biodegradable SPC isomers and homologues (e.g. C(11)SPC). Here, LAS reached the highest concentration values measured (>2 mg L(-1)), and showed a homologue distribution closer to that of commercial mixtures than LAS found at the other stations.     

Living close, doing differently: small-scale asynchrony in demography of two species of seabirds

Studies on spatiotemporal pattern of population abundance predict that close populations should exhibit a high level of synchrony, reflected in a parallel time variation of at least one demographic parameter. We tested this prediction for two threatened species of Procellariiformes sharing similar life history traits: the European Storm Petrel (Hydrobates pelagicus) and the Balearic Shearwater (Puffinus mauretanicus). Within each species, we compared adult survival, proportion of transients (breeders that do not settle), and average productivity at two neighboring colonies. Physical and environmental features (e.g., food availability) of the breeding sites were similar. However, while Balearic Shearwater colonies were free of predators, aerial predators occurred especially in one colony of the European Storm Petrel. Despite this difference, we found similar results for the two species. A high proportion of transient birds was detected in only one colony of each species, ranging between 0.00-0.38 and 0.10-0.63 for the petrels and shearwaters, respectively. This seems to be an emergent feature of spatially structured populations of seabirds, unrelated to colony size or predator pressure, that can have important demographic consequences for local population dynamics and their synchrony. Local survival of resident birds was different at each colony, an unexpected result, especially for predator-free colonies of Balearic Shearwater. Productivity varied between the two colonies of European Storm Petrels, but not between the two colonies of Balearic Shearwaters. We demonstrated that within each species, several demographic parameters were colony specific and sufficiently different to generate short-term asynchronous dynamics. Our findings suggest that, in spatially structured populations, local factors, such as predation or small-scale habitat features, or population factors, such as individual quality or age structure, can generate unexpected asynchrony between neighboring populations.     

In situ assays with tropical cladocerans to evaluate edge-of-field pesticide runoff toxicity

Tropical regions’ economy is usually based on agriculture, which involves an intensive use, and even frequent overuse, of pesticides. Nevertheless, not much research has been done on the impact of pesticides on tropical aquatic ecosystems, which are often contaminated by runoff-related pesticide inputs due to unpredictable and torrential rainfalls. This study aimed to: (i) adapt and evaluate a short-term sublethal in situ assay using post-exposure feeding as an endpoint, to the tropical cladoceran species Diaphanosoma brachyurum (collected at the Pedra do Cavalo dam in the Paraguaçu River basin, Bahia, Brazil), and, (ii) assess the role of the standard species Daphnia magna as an adequate laboratory surrogate. Lethal and sublethal (post-exposure feeding) responses were assessed for the two species. To evaluate these responses under environmentally realistic exposure conditions, a runoff event was simulated in an agricultural area previously contaminated with different deltamethrin concentrations. The resultant runoff water was used to set up microcosms with different dilutions, simulating the entrance of runoff water in an adjacent lentic system. An in situ assay with D. brachyurum was performed inside the microcosms, allowing to discriminate the effects due to deltamethrin from those due to other potential stressors associated with the experimental design (e.g. organism handling, load of suspended particles, microcosm design). Water samples were collected from microcosms to conduct a laboratory assay with D. magna. The in situ methodologies revealed to be suitable to conduct assays with D. brachyurum under tropical conditions, since all exposed organisms were successfully retrieved from the chambers. Furthermore, none of the potential stressors associated with the experimental design influenced the daphnids’ performance. The tropical cladoceran species, exposed under more realistic conditions, revealed to be more sensitive than the laboratory standard species: lethal effects were only observed for D. brachyurum and sublethal effects were noticed at a lower deltamethrin concentration for this species than for D. magna.     

Pruning waste management and climate change in Sierra Mágina’s olive groves (Andalusia,Spain)

Regional Environmental Change - In the context of climate change, concern is raising about the negative effects of some pruning waste management practices. On the one hand, burning of pruning...     

Chitosan Functionalization with Amino Acids Yields to Higher Copper Ions Adsorption Capacity

Chitosan (Chi) beads were conjugated with three different amino acids [namely, glutamic acid (GLU), methionine (MET), and taurine (TAU)] aiming to increase the divalent copper ions uptake in aqueous media. Scanning Electron Microscopy evidenced the development of a large porous structure after amino acid functionalization, associated with the increase in a number of amino groups in the polymer backbone. X-Ray Photoelectron Spectroscopy and Fourier-Transform Infrared Spectra analyses were also employed to assess the conjugation of these three different amino acids in chitosan backbone. Adsorption experiments were conducted in a batch process, at 298 K, and kinetic data indicated a slightly better fitting for the pseudo-first-order model when compared to pseudo-second order. Intraparticle diffusion model suggested a three-step mechanism for Cu(II) adsorption kinetics, limited by the third step, the intraparticle diffusion. The isotherm data fitting to the traditional Langmuir and Freundlich models indicated a better fit for the former case. The amino acid conjugation resulted in the increase of the maximum adsorption capacity for Cu(II) from 1.30 mmol g^?1 prior to amino acid conjugation to values as high as 2.31 mmol g^?1, 2.40 mmol g^?1 and 2.68 mmol g^?1 for Chi–TAU, Chi–GLU, and Chi–MET, respectively. These results are attributed to the introduction of additional amino groups and new carboxylate and amino acid residues into the chitosan backbone, which might also be explored for amino acid demanding applications.     

Measuring team trust: A critical and meta-analytical review

Team trust is gaining attention in research and practice due to its benefits for team performance, yet clarity about the intricacies of its measurement is needed. Therefore, we meta-analyzed 118 studies (N = 7,738) to untangle the role of measurement features by investigating the degree to which they influence the trust–performance relationship. Results showed that the trust–performance relationship is contingent upon time lag and source of measurement. Specifically, cross-sectional and single-source studies produced higher effect sizes than time-lagged and different-source studies. In contrast, the moderating roles of conceptualization–operationalization alignment and referent of trust measures were not supported. Post hoc analyses revealed that affective trust is more strongly related to global, versus specific team outcomes, and that mixed-referent items are particularly effective within intact teams, whereas the trust–performance relationship is constrained when direct consensus items are used within ad hoc teams. Furthermore, we provided a critical review that highlights the importance of composites, multilevel forces, and item content and wording. Finally, we clarified key gaps in the literature, calling for research where needed. This review serves as a bridge between conceptualization and measurement and lays the groundwork for advancing knowledge of team trust.     

Comparative study on the susceptibility of freshwater species to copper-based pesticides

Copper compounds have been intentionally introduced into water bodies as aquatic plant herbicides, algicides and molluscicides. Copper-based fertilizers and fungicides have been widely used in agriculture as well. Despite the fact that copper is an essential element for all biota, elevated concentrations of this metal have been shown to affect a variety of aquatic organisms. Nonetheless, comparative studies on the susceptibility of different freshwater species to copper compounds have seldom been performed. This study was conducted to compare toxicity of copper-based pesticides (copper oxychloride, cuprous oxide and copper sulfate) to different freshwater target (Raphidocelis subcapitata, a planktonic alga and Biomphalaria glabrata, a snail) and non-target (Daphnia similis, a planktonic crustacean and Danio rerio, a fish) organisms. Test water parameters were as follows: pH = 7.4 +/- 0.1; hardness 44 +/- 1 mg/l as CaCO3; DO 8-9 mg/l at the beginning and > 4 mg/l at the end; temperature, fish and snails 25 +/- 1 degrees C, Daphnia 20 +/- 2 degrees C, algae 24 +/- 1 degrees C. D. similis (immobilization), 48-h EC50s (95% CLs) ranging from 0.013 (0.011-0.016) to 0.043 (0.033-0.057) mg Cu/l, and R. subcapitata (growth inhibition), 96-h IC50s from 0.071 (0.045-0.099) to 0.137 (0.090-0.174) mg Cu/l, were the most susceptible species. B. glabrata (lethality), 48-h LC50s from 0.179 (0.102-0.270) to 0.854 (0.553-1.457) mg Cu/l, and D. rerio (lethality), 48-h LC50s 0.063 (0.045-0.089), 0.192 (0.133-0.272) and 0.714 (0.494-1.016) mg Cu/l, were less susceptible than Daphnia to copper-based pesticides. Findings from the present study therefore suggest that increased levels of copper in water bodies is likely to adversely affect a variety of aquatic species.