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.

Mercury in the sediments of the Marano and Grado Lagoon (northern Adriatic Sea): Sources, distribution and speciation

Abstract: The existence of mining tailings in Idrija (Slovenia) and their subsequent transportation via the Isonzo River has been the primary source of mercury (Hg) in the northern Adriatic Sea for almost 500 years, making the Gulf of Trieste and the adjacent Marano and Grado Lagoon two of the most contaminated marine areas in the world. A further, more recent, contribution of Hg has been added by the operation of a chlor-alkali plant (CAP) located in the drainage basin flowing into the Lagoon. On the basis of previous research, as well as new data obtained from the “MIRACLE” project (Mercury Interdisciplinary Research for Appropriate Clam farming in a Lagoon Environment), the spatial distribution of Hg and its relationships with methylmercury (MeHg), organic matter and several geochemical parameters in surface sediments were investigated. The predominant and long-term impacts of the cinnabar-rich Isonzo River particulate matter in the Lagoon surface sediments are evident and confirmed by a decreasing concentration gradient from east (>11 μg g−1) to west (0.7 μg g−1). Hg originated from the CAP is only significant in the central sector of the Lagoon. Hg is primarily associated with fine-grained sediments (<16 μm), as a consequence of transport and dispersion from the fluvial source through littoral and tidal currents. However, speciation analyses highlighted the presence of Hg sulphides in the coarse sandy fraction of sediments from the eastern area, as expected given the origin of the sedimentary material. Unlike Hg, the distribution of MeHg (0.47–7.85 ng g−1) does not show a clear trend. MeHg constitutes, on average, 0.08% of total Hg and percentages are comparable to those obtained in similar lagoon environments. Higher MeHg concentrations in low to intermediate Hg-contaminated sediments indicate that the metal availability is not a limiting factor for MeHg occurrence, thus suggesting a major role played by environmental conditions and/or speciation. The reasonably good correlation between MeHg normalized to humic acid (HA) content and humic δ13C indicates that MeHg is preferentially associated with autochthonous δ13C-enriched HAs in lagoon surface sediments, suggesting that the structure of “marine” HAs, less refractory and less aromatic, could favor MeHg binding and/or production. In the context of the potential hazard of Hg and MeHg accumulation in reared clams, the choice of a site for the extension of farming activities inside the Marano and Grado Lagoon is dependent on several factors and cannot be decided solely on the basis of the total Hg content in the sediment.

Thermal characteristics of permafrost in the steep alpine rock walls of the Aiguille du Midi (Mont Blanc Massif, 3842 m a.s.l)

Abstract: . Permafrost and related thermo-hydro-mechanical processes are thought to influence high alpine rock wall stability, but a lack of field measurements means that the characteristics and processes of rock wall permafrost are poorly understood. To help remedy this situation, in 2005 work began to install a monitoring system at the Aiguille du Midi (3842 m a.s.l). This paper presents temperature records from nine surface sensors (eight years of records) and three 10 m deep boreholes (4 years of records), installed at locations with different surface and bedrock characteristics. In line with previous studies, our temperature data analyses showed that: micro-meteorology controls the surface temperature, active layer thicknesses are directly related to aspect and ranged from

Climate variability in north-western Italy during the second half of the 20th century

Abstract: We analyse a large set of daily temperature and precipitation time series measured by a dense observational network in north-western Italy, in the period from 1952 to 2002. We find that average temperatures display a significant increase of about 1 °C over the period of observation. The increase is particularly evident for maximum daily temperatures in winter and summer months. By contrast, precipitation time series display no significant trend over the last fifty years. We also determine the statistical properties of interannual fluctuations in temperature and precipitation, and quantify their correlation with large-scale atmospheric patterns and global indices such as the North Atlantic Oscillation (NAO), the Scandinavian pattern (SCAN) and European Blocking (EB). The positive phase of the Scandinavian pattern and the presence of frequent blocking episodes are found to be significantly correlated with increased summer and fall precipitation and cold temperatures in the study area.