Dramatic effect of pop-up satellite tags on eel swimming

The journey of the European eel to the spawning area in the Sargasso Sea is still a mystery. Several trials have been carried out to follow migrating eels with pop-up satellite tags (PSATs), without much success. As eels are very efficient swimmers, tags likely interfere with their high swimming efficiency. Here we report a more than twofold increase in swimming cost caused by a regular small satellite tag. The impact was determined at a range of swimming speeds with and without tag in a 2-m swimming tunnel. These results help to explain why the previous use of PSATs to identify spawning sites in the Sargasso Sea was thus far unsuccessful.     

Blood lead levels and nutrition in an urban community in Venezuela

Previous lead (Pb) exposure studies identified the Michelena sector in Valencia as a ‘critical’ area for Pb contamination. An analytical-ecological study was designed to evaluate the association of environmental and nutritional variables with blood lead (BPb) in children attending two schools located in this sector. A questionnaire was administered and the findings were correlated with BPb and serum-calcium (S-Ca) levels. The total population examined included 60 children (4–9 years old). The mean BPb values was 10.5?±?3?ug/dL (61.7%?≥?10?ug/dL) and the mean S-Ca was 8.9?±?0.7?mg/dL. A significant difference (p?=?0.042) was found between BPbs in males (11.1?±?3.1?ug/dL) when compared with females (9.6?±?2.8?ug/dL). Child age, school, schedule at school, parents' occupational exposure, habits, and socioeconomic status had no significant association with BPbs. The relationship between BPb levels (dependent variable) and the S-Ca and daily Ca intake levels (independent variables) was analysed through multiple regression analysis. The results show an inverse relationship between BPb and both variables (β?=??0.073, and β?=??0.001) respectively, with the daily Ca intake being the only significant variable in the model (p?=?0.04). Although average BPbs was not very high, the percentage of children with BPbs higher than the US-CDC intervention level was greater than those found in other studies. Since detailed information is generally unavailable for these children in Venezuela, this study provides insights for future research.     

Mechanisms of moisture stress in a mid-latitude temperate forest: Implications for feedforward and feedback controls from an irrigation experiment

While it is well established that stomata close during moisture stress, strong correlations among environmental (e.g., vapor pressure deficit, soil moisture, air temperature, radiation) and internal (e.g., leaf water potential, sap flow, root-shoot signaling) variables obscure the identification of causal mechanisms from field experiments. Models of stomatal control fitted to field data therefore suffer from ambiguous parameter identification, with multiple acceptable (i.e., nearly optimal) model structures emphasizing different moisture status indicators and different processes. In an effort to minimize these correlations and improve parameter and process identification, we conducted an irrigation experiment on red maples (Acer rubrum L.) at Harvard Forest (summers of 2005 and 2006). Control and irrigated trees experienced similar radiative and boundary layer forcings, but different soil moisture status, and thus presumably different diurnal cycles of internal leaf water potential. Measured soil moisture and atmospheric forcing were used to drive a transient tree hydraulic model that incorporated a Jarvis-type leaf conductance in a Penman–Monteith framework with a Cowan-type (resistance and capacitance) tree hydraulic representation. The leaf conductance model included dependence on both leaf matric potential, Ψ_L (so-called feedback control) and on vapor pressure deficit, D (so-called feedforward control). Model parameters were estimated by minimizing the error between predicted and measured sap flow. The whole-tree irrigation treatment had the effect of elevating measured transpiration during summer dry-downs, demonstrating the limiting effect that subsurface resistance may have on transpiration during these times of moisture stress. From the best fitted model, we infer that during dry downs, moisture stress manifests itself in an increase of soil resistance with a resulting decrease in Ψ_L, leading to both feedforward and feedback controls in the control trees, but only feedforward control for the irrigated set. Increases in the sum-of-squares error when individual model components were disabled allow us to reject the following three null hypotheses: (1) the f(D) stress is statistically insignificant (p = 0.01); (2) the f(Ψ_L) stress is statistically insignificant (p = 0.07); and (3) plant storage capacitance is independent of moisture status (p = 0.07).     

Effect of heating rate on the pyrolysis of high-impact polystyrene containing brominated flame retardants: fate of brominated flame retardants

In the case of plastics containing brominated flame retardants, various brominated organic compounds, including polybrominated dibenzodioxins and dibenzofurans, are yielded when they are degraded. In order to reduce the hazard that might be generated during after-live treatment, the behaviour of flame retarded high-impact polystyrene containing decabromo diphenylether and antimony oxide (Sb₂O₃), was investigated using several heating programs. It was found that the separation of the thermal process into two steps divided at 330?°C makes it possible to obtain an oil fraction rich in brominated compounds at low temperatures and an oil fraction depleted in brominated compounds at high temperatures. The low temperature oil contained a high concentration of SbBr₃ and dibromodibenzofurans. Various brominated compounds with a low volatility and 1-bromo-1-phenylethane from the reaction of HBr with styrene were among the substances in the high temperature oil. The concentration of brominated compounds was reduced from 6?wt% for degradation in a single step to below 1?wt% in the high temperature oil in the two step process.     

Feedstock recycling of waste polymeric material

The first International Symposium on Feedstock Recycling of Polymeric Materials (ISFR) was hosted in 1999 in Sendai, Japan. Since then, the ISFR has been held five times in different places in Asia and Europe. Each of these conferences focused on special issues covered by the Journal of Material Cycles and Waste Management. The topics included thermal processes with and without catalysts, wet processes in various solvents, the dehydrochlorination of PVC, mechanical recycling and separation techniques, as well as the treatment of biomaterials. This review is a compilation of the most interesting and important developments discussed at the ISFR during the last decade.     

Natural and enhanced biodegradation of propylene glycol in airport soil

Aircraft de-icing fluids (ADF) are a source of water and soil pollution in airport sites. Propylene glycol (PG) is a main component in several commercial formulations of ADFs. Even though PG is biodegradable in soil, seasonal overloads may result in occasional groundwater contamination. Feasibility studies for the biostimulation of PG degradation in soil have been carried out in soil slurries, soil microcosms and enrichment cultures with and without the addition of nutrients (N and P sources, oligoelements), alternative electron acceptors (nitrate, oxygen releasing compounds) and adsorbents (activated carbon). Soil samples have been taken from the contaminated area of Gardermoen Airport Oslo. Under aerobic conditions and in the absence of added nutrients, no or scarce biomass growth is observed and PG degradation occurs by maintenance metabolism at constant removal rate by the original population of PG degraders. With the addition of nutrient, biomass exponential growth enhances aerobic PG degradation also at low temperatures (4 ° C) that occur at the high season of snowmelt. Anaerobic PG degradation without added nutrients still proceeds at constant rate (i.e. no biomass growth) and gives rise to reduced fermentation product (propionic acid, reduced Fe and Mn, methane). The addition of nitrate does not promote biomass growth but allows full PG mineralization without reduced by-products. Further exploitation on the field is necessary to fully evaluate the effect of oxygen releasing compounds and adsorbents.     

Analysis of the cost-effectiveness for ecosystem service provision and rural income generation: a comparison of three different programs in Southern Ecuador

In recent years, new tools for funding nature conservation have been designed. Because poverty is often significant in areas with high biodiversity, the improvement of local livelihoods is frequently considered as a secondary goal of new financing mechanisms besides nature conservation. The buffer zone of the Podocarpus National Park in Ecuador is such a high biodiversity zone. In this paper, we compare the cost-effectiveness and development potential of three different mechanisms to finance nature conservation implemented in this buffer zone, namely (a) an organic coffee label, (b) the Socio Bosque Program, a nationwide payment scheme for private forest conservation, and (c) FORAGUA, a regional water fund. This paper describes the functioning and the scope of the mechanisms and analyses their environmental and socio-economic impacts which are compared to the total costs. Results show that the water fund has the highest additionality in ecosystem service provision, while the payment scheme is the most cost-effective both for current as for increased ecosystem service provision and for extra rural job creation. Organic coffee certification has the highest positive impact on rural income creation.     

Spatial scales of variation in lichens: implications for sampling design in biomonitoring surveys

The variability of biological data is a main constraint affecting the quality and reliability of lichen biomonitoring surveys for estimation of the effects of atmospheric pollution. Although most epiphytic lichen bioindication surveys focus on between-site differences at the landscape level, associated with the large scale effects of atmospheric pollution, current protocols are based on multilevel sampling, thus adding further sources of variation and affecting the error budget. We test the hypothesis that assemblages of lichen communities vary at each spatial scale examined, in order to determine what scales should be included in future monitoring studies. We compared four sites in Italy, along gradients of atmospheric pollution and climate, to test the partitioning of the variance components of lichen diversity across spatial scales (from trunks to landscapes). Despite environmental heterogeneity, we observed comparable spatial variance. However, residuals often overcame between-plot variability, leading to biased estimation of atmospheric pollution effects.     

Frozen mitochondria as rapid water quality bioassay

A rapid and relatively low cost bioassay, usable in routine screening water test has been developed modifying the beef heart mitochondria test. In our experiments, mitochondria (FM22) were frozen at -22 degrees C, instead of -80 degrees C (FM80), and their applicability and sensitivity was verified. The oxygen consumption was measured by a Clark electrode that was interfaced to a PC to collect test analysis data. Blank tests were carried out to verify the oxygen consumption linear fitting. Toxicity tests were performed using pure organic and inorganic compounds, such to verify the FM22 sensitivity. A piecewise regression, through an Excel Macro, identified the break-point in the oxygen consumption and calculated the toxicity. The IC50s of the tested compounds were calculated and ranged from 0.123 to 0.173 mg/l for heavy metals (Cd, Cr, Cu, Ni, Pb and Zn) and from 0.572 to 10.545 mg/l for organics (benzene, DMSO, DDE, endrin, dichloromethane, chlorobenzene, 1,2-dichlorobenzene and 1,3-dichlorobenzene). Water effluent samples were then tested. The FM22 gave different toxic reactions to them. Water samples were characterised for heavy metals. The FM22 bioassay had a higher sensitivity than the FM80 and a high reproducibility in the toxicity test with pure compounds. The FM22 test was a good predictor of toxicity for water samples; the bioassay is easy, low cost and rapid, then usable for routine tests.