ARPA-E

About: ARPA-E is a government organization based out in Washington D.C., District of Columbia, United States. It is known for research contribution in the topics: Population & Climate change. The organization has 1161 authors who have published 1267 publications receiving 30049 citations. The organization is also known as: Advanced Research Projects Agency - Energy.

Detection of trace elements in freshwater macrobenthic invertebrates of different functional feeding guilds: A case study in Northeast Italy

Abstract: Trace elements are common contaminants in aquatic ecosystems; their detection in biota yields information on their availability in the environment and provides an indirect indication of freshwater ecological status. We analyzed samples of freshwater macrobenthic invertebrates from six watercourses in Friuli Venezia-Giulia (Northeast Italy) to verify whether trace elements accumulation is related to their ecological status sensu Water Framework Directive (WFD), and to determine tropic level influences on the accumulation of 18 trace elements in macrobenthic communities. Observed concentrations could be in line with results of ecological status assessment defined by the WFD, in fact two sites classified as “Moderate” had the highest trace elements content. The genus Calopteryx (Odonata, predator) was positively correlated with Be, Cr, Fe, Mn, Mo, Ni, Sn, and V (ρS range 0.777–0.844). Positive correlations were also determined for the genus Rhyacophila (Trichoptera, predator) with Cu (ρS = 0.757), suggesting bioaccumulation in macroinvertebrate tissue. Ephemeroptera of the genus Caenis (collector-gatherers) were positively correlated with Be, Fe, Mn, Pb, Sb, and V (ρS range 0.757–0.802), indicating that ingestion of sediment is the most effective uptake of these metals. Results of this study, albeit preliminary, showed that trace elements detection in aquatic macrobenthic invertebrates is a useful analysis for obtaining information about the status of freshwater course. Our study provides evidence for a greater accumulation of trace elements in predators and collector-gatherers, suggesting that the tropic level of macrobenthic communities influence the accumulation of trace elements.

Modelling Pollutant Dispersion in a Street Network

Abstract: This study constitutes a further step in the analysis of the performances of a street network model to simulate atmospheric pollutant dispersion in urban areas. The model, named SIRANE, is based on the decomposition of the urban atmosphere into two sub-domains: the urban boundary layer, whose dynamics is assumed to be well established, and the urban canopy, represented as a series of interconnected boxes. Parametric laws govern the mass exchanges between the boxes under the assumption that the pollutant dispersion within the canopy can be fully simulated by modelling three main bulk transfer phenomena: channelling along street axes, transfers at street intersections, and vertical exchange between street canyons and the overlying atmosphere. Here, we aim to evaluate the reliability of the parametrizations adopted to simulate these phenomena, by focusing on their possible dependence on the external wind direction. To this end, we test the model against concentration measurements within an idealized urban district whose geometrical layout closely matches the street network represented in SIRANE. The analysis is performed for an urban array with a fixed geometry and a varying wind incidence angle. The results show that the model provides generally good results with the reference parametrizations adopted in SIRANE and that its performances are quite robust for a wide range of the model parameters. This proves the reliability of the street network approach in simulating pollutant dispersion in densely built city districts. The results also show that the model performances may be improved by considering a dependence of the wind fluctuations at street intersections and of the vertical exchange velocity on the direction of the incident wind. This opens the way for further investigations to clarify the dependence of these parameters on wind direction and street aspect ratios.

Picocyanobacteria in Adriatic transitional environments

Abstract: In the marine realm picoplanktonic cyanobacteria (PC) show a broad distribution from the surface ocean to the offshore and coastal waters of semi-enclosed seas and, because of their photoheterotrophy, they are responsible for a substantial fraction of both primary production and organic matter degradation/utilization. In the present study, we investigated PC distribution related to some physical–chemical parameters (temperature, salinity and dissolved oxygen), in the most productive periods of the year, spring and fall, at 37 stations located in seven transitional systems all along the Italian coast of the Adriatic Sea: Grado and Marano, Venezia, Pialassa Baiona, Margherita di Savoia, Torre Guaceto, Cesine and Alimini. The aim of the study was to determine if PC are common elements of these transitional systems (lagoons, marshes and solar salterns) or whether they are only occasionally important during stochastic bloom events. PC mean abundances were all over the seven habitats more than one order of magnitude higher (>5 × 107 cells L−1) than those found in coastal and offshore waters of the Adriatic Sea. Their range of variability was also broader (105–109 cells L−1 vs. 106–108 cells L−1). PC populations appeared well adapted to ample variations in salinity (5–87). The highest abundances (close to 109 cells L−1) were found at extremely high/low salinity values. Even oxygen concentrations close to hypoxia did not seem to negatively affect PC abundances. Because of their ability in adapting to extreme conditions, PC may become the prevailing fraction of the phototrophic plankton in these sites and their role in such ecosystems should not be underestimated.

Heavy Metals Distribution in Suspended Particulate Matter and Sediment Collected from Vlora Bay (Albania): A Methodological Approach for Metal Pollution Evaluation

Abstract: Heavy metals (Al, Fe, As, Cd, Cr, Cu, Hg, Mn, Ni, Pb, Zn) content was evaluated in suspended particulate matter and sediment samples collected from Vlora Bay (Albania) in the framework of Centro Internazionale di Scienze del Mare (CISM) Project activities. The trend of the metals (in general, overlapping that showed by the suspended particulate matter distribution), together with the linear correlation values found between metals, suggested the pivotal role of the Vjosa River and of the inner circulation scheme of Vlora Bay on their distribution. The geoaccumulation index, Igeo, was calculated as a criterion to assess if a metal concentration found in the sediment represents contamination level or can be considered as background level. The results show that metals concentrations in sediments can be considered near the background levels found in the Mediterranean Sea, even if some accumulation was found in several stations. The data were compared to Sediment Quality Guidelines considering the ERL ...