Ecological changes in historically polluted soils: Metal(loid) bioaccumulation in microarthropods and their impact on community structure

International audienceSoil pollution by persistent metal(loid)s present environmental and sanitary risks. While the effects of metal(loid)s on vegetation and macrofauna have been widely studied, their impact on microarthropods (millimetre scale) and their bioaccumulation capacity have been less investigated. However, microarthropods provide important ecosystem services, contributing in particular to soil organic matter dynamics. This study focussed on the impact of metal(loid) pollution on the structure and distribution of microarthropod communities and their potential to bioaccumulate lead (Pb). Soil samples were collected from a contaminated historical site with a strong horizontal and vertical gradient of Pb concentrations. Microarthropods were extracted using the Berlese method. The field experiments showed that microarthropods were present even in extremely polluted soils (30,000 mg Pb kg− 1). However, while microarthropod abundance increased with increasing soil C/N content (R2 = 0.79), richness decreased with increasing pollution. A shift in the community structure from an oribatid-to a springtail-dominated community was observed in less polluted soils (R2 = 0.68). In addition, Pb bioamplification occurred in microarthropods, with higher Pb concentrations in predators than in detritivorous microarthropods. Finally, the importance of feeding and reproductive ecological traits as potentially relevant descriptors of springtail community structures was highlighted. This study demonstrates the interest of microarthropod communities with different trophic levels and ecological features for evaluating the global environmental impact of metal(loid) pollution on soil biological quality

Scientific Opinion addressing the state of the science on risk assessment of plant protection products for in-soil organisms

Following a request from EFSA, the Panel on Plant Protection Products and their Residues developed an opinion on the science behind the risk assessment of plant protection products for in-soil organisms. The current risk assessment scheme is reviewed, taking into account new regulatory frameworks and scientific developments. Proposals are made for specific protection goals for in-soil organisms being key drivers for relevant ecosystem services in agricultural landscapes such as nutrient cycling, soil structure, pest control and biodiversity. Considering the time-scales and biological processes related to the dispersal of the majority of in-soil organisms compared to terrestrial non-target arthropods living above soil, the Panel proposes that in-soil environmental risk assessments are made at in- and off-field scale considering field boundary levels. A new testing strategy which takes into account the relevant exposure routes for in-soil organisms and the potential direct and indirect effects is proposed. In order to address species recovery and long-term impacts of PPPs, the use of population models is also proposed

Estación Experimental de Aula Dei. Memoria anual 2014

67 Pags.Esta memoria recoge la actividad científica de la Estación Experimental de Aula Dei (EEAD-CSIC) durante el año 2014, conteniendo información específica sobre las siguientes actividades de la EEAD-CSIC: Publicaciones (ISI y no ISI; Actas de congresos; Libros y Capítulos de Libro), Transferencia tecnológica, Tesis, Congresos, Cursos, Seminarios, Estancias, Actividades de cultura científica, Eventos. Incluye, además, un informe de financiación, directorio del personal en activo durante el año y tabla-resumen de las estadísticas relacionadas con los procesos técnicos y servicios de la Unidad Técnica de Biblioteca y Documentación.Peer reviewe

Advancements and prospects of thermal management and waste heat recovery of PEMFC

Despite that the Proton Exchange Membrane Fuel Cell (PEMFC) is considered to be an efficient power device; around half of the energy produced from the electrochemical reaction is dissipated as heat due to irreversibility of the cathodic reaction, Ohmic resistance, and mass transport overpotentials. Effective heat removal from the PEMFC, via cooling, is very important to maintain the cell/stack at a uniform operating temperature ensuring the durability of the device as excessive operating temperature may dry out the membrane and reduces the surface area of the catalyst hence lowering the performance of the cell. In addition to cooling, capturing the produced heat and repurposing it using one of the Waste Heat Recovery (WHR) technologies is an effective approach to add a great economic value to the PEMFC power system. Global warming, climate change, and the high cost of energy production are the main drivers to improve the energy efficiency of PEMFC using WHR. This paper presents an overview of the recent progress concerning the cooling strategies and WHR opportunities for PEMFC. The main cooling techniques of PEMFCs are described and evaluated with respect to their advantages and disadvantages. Additionally, the potential pathways for PEMFC-WHR including heating, cooling, and power generation are explored and assessed. Furthermore, the main challenges and the research prospects for the cooling strategies and WHR of PEMFCs are discussed

Trophic niche differentiation, sex ratio and phylogeography of European Collembola

Collembola are important soil-dwelling animals reaching high diversity and density. For understanding driving factors for Collembola density and diversity this study investigated (1) trophic niche differentiation of Collembola species using stable isotope analysis, (2) mode of reproduction and sex ratios in the field, (3) colonization of new habitats by parthenogenetic and sexual species and (4) the genetic variation in parthenogenetic and sexual species in Europe. To evaluate trophic niche differentiation the natural variation in nitrogen isotopes was assessed in 20 Collembola taxa from three deciduous forests stands. The 15N gradient spanned over 9 units, which implies a wide range in food sources used. Assuming a shift in 15N of about 3 ‰ per trophic level, the results indicate a range of three trophic levels. The 15N signature formed a continuum from phycophages/herbivores to primary and secondary decomposers, reflecting a gradual shift from more detrital to more microbial diets. These results suggest that trophic niche differentiation is an important mechanism for the maintenance of the high number of Collembola species in forst ecosystems. The sex ratios of Collembola species were assessed in a temperate oak-beech forest in two months intervals during one year. A total of 6 species, including the abundant Mesaphorura machrochaeta, Parisotoma notabilis, Neanura muscorum and Isotomiella minor formed pure female populations suggesting that they reproduced by parthenogenesis. A total of 22 species including the common species Folsomia quadrioculata, Protaphorura fimata and Lepidocyrtus lignorum formed bisexual populations, suggesting that sexual reproduction predominates in Collembola of the studied forest. In agreement with earlier studies parthenogenetic species predominated deeper in the soil (euedaphic species), but some parthenogenetic species were hemiedaphic. The sex ratio of bisexual Collembola species in the litter layer generally was more female biased than that in the mineral soil. Presumably, females concentrate at sites with high density of resources whereas males are relatively more abundant at sites more favourable for spermatophore placement. Sexual and parthenogenetic species may respond differently to environmental changes, e.g. to the availability of resources. We hypothesized that parthenogenetic species are more sensitive to resource depletion than sexual species, and that they will colonize available habitats faster due to their faster mode of reproduction. In contrast to our hypotheses, parthenogenetic and sexual Collembola species were similarly affected by resource depletion. In agreement with our hypothesis, the proportion of parthenogenetic species increased with time when free habitats and plenty of resources were available, indicating that parthenogenetic species are faster colonizers. Intraspecefic genetic variation was investigated using molecular markers, mtDNA (COI) in two sexual species, Folsomia quadrioculata and Ceratophysella denticulata, and two parthenogenetic species, Parisotoma notabilis and Isotomiella minor. The variation of mtDNA (COI) showed Collembola species comprises of ancient lineages which colonized Europe in particular southern and central Europe in the pre-Pleistocene irrespective of the mode of reproduction. In each of the species studied lineages were separated by deep splits, especially in central and southern regions, suggesting that the colonization of Europe by these species predates the Pleistocene, potentially dating back to the lower Tertiary. Recent colonization by Collembola species of some locations especially in the north including Scandinavia, Marion Island, Ringnes Island and Siberia was inferred. The hypothesis that central European Collembola populations originated from southern refugia after the last glaciation was rejected. The deep splits in each of the four Collembola species studied indicate that Collembola species in general constitute of a number of cryptic species with complex phylogeographic history

Investigating the Effects of the Block Geometries and Sidewall Divergences on the Local Scour Downstream of Baffled Chute Spillways

Due to the lack of any specific study about the sidewalls and other blocks’ changes in the case of hydraulic and scour downstream, the present study was conducted to investigate this issue. For this purpose, drainage projects and spillway chutes, as well as many baffle block chutes, were designed and constructed with the parallel sidewalls and trapezoidal shape using the U.S. Bureau of Reclamation (USBR) instructions. Three divergence ratios of b1/b2=1.45,1.75, and 2.45, a parallel sidewall of b1/b2=1, and also three geometry blocks including trapezoidal USBR, trihedral, and semicircle blocks were applied and tested in the hydraulic laboratory using a baffle chute with the slope of (2 : 1), (H : V). The material used in this study was sediment sand with a uniform grain size of d50 = 1.2 mm, 15 cm of thickness, and 2 m of length. The experiment was conducted with seven different discharges in lasting condition, and the flow characteristic and scour hole dimensions were measured. The results revealed that in comparison with the USBR blocks, changes in the baffle sidewall and block shape made an approximate 50% reduction in the maximum depth of the scour hole. Thus, increasing the divergence ratio from 1 to 2.45 had a significant effect on reducing the maximum depth and the topographic shape of the scour hole. According to the range mentioned in the literature for the Weber number, the scale effect was negligible for the chute with baffle blocks. Generally, it can be concluded that the sidewall changes also can make a reduction in the number of overbaffle blocks, causing a reduction in the construction cost