Antarctic Special Protected Area 161 as a Reference to Assess the Effects of Anthropogenic and Natural Impacts on Meiobenthic Assemblages

The Antarctic region is usually considered a pristine area. Nevertheless, regional warming effects and increasing human activities, including the presence of several research stations, are inducing considerable environmental changes that may affect the ecosystem’s functions. Therefore, during the XXXIII Antarctic expedition, we carried out an investigation in Terra Nova bay (Ross Sea), close to the Antarctic Specially Protected Area (ASPA) n.161. In particular, we compared the effects of two different types of impacts on the meiobenthic assemblages: anthropogenic impact (AI), associated with the activity of Mario Zucchelli Research Station (MZS), and natural impact (NI) attributable to a large colony of Adélie penguins (Pygoscelis adeliae) in Adelie Cove. For each impacted site, a respective control site and two sampling depths (20 and 50 m) were selected. Several environmental variables (pH, dissolved oxygen, major and minor ions, heavy metals, organic load, and sediment grain size) were measured and analysed, to allow a comprehensive characterization of the sampling areas. According to the criteria defined by Unites States Environmental Protection Agency (US EPA 2009), heavy metal concentrations did not reveal critical conditions. However, both the MZS (AI20) and penguin colony (NI20) sites showed higher heavy metal concentrations, the former due to human activities related to the Italian research station, with the latter caused by the penguins excrements. Meiobenthic richness and abundance values suggested that the worst ecological condition was consistently related to the Adélie penguins colony. Furthermore, the higher contribution of r-strategists corroborates the hypothesis that the chronic impact of the penguin colonies may have stronger effects on the meiobenthos than the human activities at the MZS. Food is not limited in shallow Antarctic bottoms, and microscale differences in primary and secondary production processes can likely explain the greater spatial heterogeneity, highlighted both by the univariate and multivariate attributes of meiobenthic assemblage (i.e., richness, diversity, abundance, whole structure assemblage, and rare taxa) at the deeper stations. As reported in other geographical regions, the assemblage structure of rare meiobenthic taxa is confirmed to be more susceptible to environmental variations, rather than the whole assemblage structure

Source apportion of atmospheric particulate matter: A joint Eulerian/Lagrangian approach

PM2.5 samples were collected during an annual monitoring campaign (January 2012–January 2013) in the urban area of Naples, one of the major cities in Southern Italy. Samples were collected by means of a standard gravimetric sampler (Tecora Echo model) and characterized from a chemical point of view by ion chromatography. As a result, 143 samples together with their ionic composition have been collected. We extend traditional source apportionment techniques, usually based on multivariate factor analysis, interpreting the chemical analysis results within a Lagrangian framework. The Hybrid Single-Particle Lagrangian Integrated Trajectory Model (HYSPLIT) model was used, providing linkages to the source regions in the upwind areas. Results were analyzed in order to quantify the relative weight of different source types/areas. Model results suggested that PM concentrations are strongly affected not only by local emissions but also by transboundary emissions, especially from the Eastern and Northern European countries and African Saharan dust episodes

Vertical transport of PM2.5 and PM10 and its source identification in the street canyons of Chennai metropolitan city, India

Chemical characterization of particulate matter (PM) measured along trafficked roads in Chennai city was performed during the winter season. Several heights, from 3 m to about 38 m above the ground level, and road geometries were taken into account. The daily average coarse (PM10) and fine (PM2.5) particles concentrations were in the range 72–110 (for PM10) and 34–57 μg/m3 (for PM2.5), depending on the site. Samples were analyzed in terms of inorganic ions using Ion Chromatography (IC) and elements by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Results indicated the dominance of SO42− followed by Na+,Ca2+,NO3− and Cl− ions in the coarse fraction; similarly, in the fine fraction ion concentrations decreased in the following order: SO42−, NH4+, K+ and Ca2+. Among the elements, crustal element (Al, Fe) and Zn concentrations were much higher (accounting about 90% of the total elemental concentration) than other toxic elements (Cr, Cu, Mn, Ni, Pb, Sn, Ti and V). No element showed a significant dependence on height, expect for calcium at site ‘Velachery’ which contributed significantly to the abundance of the coarse fraction mass. In order to identify the major sources of air pollution, the collected data were analyzed using Positive Matrix Factorization (PMF), allowing to highlight five dominant pollution sources/factors: secondary PM, road traffic, biomass burning, sea spray and crustal erosion. Overall, the present study provided a new insight for the source apportionment of monitored pollutants in the Chennai city

Size-segregated aerosol fluxes, deposition velocities, and chemical composition in an Alpine valley

The paper presents eddy covariance measurements of aerosol fluxes performed above an Alpine pasture in the Camonica Valley (Italian Alps) during summer 2019 and winter 2020. Vertical fluxes and deposition velocities (vds) were computed for nine aerosol size classes, with geometric mean diameters (GMDs) ranging from 10 nm to 0.76 μm, employing a fast-response electrical low-pressure impactor (ELPI+, Dekati, FI). At the end of each campaign, the concentration of water-soluble ions was estimated from the ion chromatography chemical speciation performed on the multi-impactor filters. K+ concentrations tripled in winter, evidencing the impact of biomass burning emissions, while nitrate, nitrite, ammonium, and sulphate were ascribed to secondary inorganic aerosol (SIA) formation. During summer, classes characterized by downward net daily fluxes presented a high percentage of SIA (> 70%) deposited on the respective filters. Phenomena of growth or coagulation of particles were also detected from the steady increase in concentrations during the day in classes with GMD ≥ 20 nm. Turbulence favoured intense aerosol exchange during the day. During summer nights, low friction velocities (u∗) led to weaker fluxes, while a strong, stable stratification in winter determined aerosol trapping at ground level and non-negligible, mostly negative, fluxes during nighttime. The trends of vds versus aerosol GMDs showed prevailing deposition phenomena under stable atmospheric conditions, with relative humidity higher than or equal to 90%, friction velocity lower than 0.15 m s−1, or wind speed lower than 2 m s−1. Cluster analysis identified groups of days with or without nucleation events and highlighted a rainout effect in summer during a period characterized by intense precipitation