Jacopo Gabrieli

Post 17th century changes of European lead emissions recorded in high-altitude Alpine snow and ice

The occurrence of organic pollutants in European Alpine snow/ice has been reconstructed over the past three centuries using a new online extraction method for polycyclic aromatic hydrocarbons (PAH) followed by liquid chromatographic determination. The meltwater flow from a continuous ice core melting system was split into two aliquots, with one aliquot directed to an inductively coupled plasma quadrupole mass spectrometer for continuous trace elements determinations and the second introduced into a solid phase C18 (SPE) cartridge for semicontinuous PAH extraction. The depth resolution for PAH extractions ranged from 40 to 70 cm, and corresponds to 0.7-5 years per sample. The concentrations of 11 PAH were determined in dated snow/ice samples to reconstruct the atmospheric concentration of these compounds in Europe for the last 300 years. The PAH pattern is dominated by phenanthrene (Phe), fluoranthene (Fla), and pyrene (Pyr), which represent 60-80% of the total PAH mass. Before 1875 the sum of PAH concentration (SigmaPAH) was very low with total mean concentrations less than 2 ng/kg and 0.08 ng/kg for the heavier compounds (SigmaPAH*, more than four aromatic rings). During the first phase of the industrial revolution (1770-1830) the PAH deposition showed a weak increase which became much greater from the start of the second phase of the industrial revolution at the end of 19th Century. In the 1920s, economic recession in Europe decreased PAH emissions until the 1930s when they increased again and reached a maximum concentration of 32 ng/kg from 1945 to 1955. From 1955 to 1975 the PAH concentrations decreased significantly, reflecting improvements in emission controls especially from major point sources, while from 1975 to 2003 they rose to levels equivalent to those in 1910. The Fla/(Fla+Pyr) ratio is often used for source assignment and here indicates an increase in the relative contribution of gasoline and diesel combustion with respect to coal and wood burning from 1860 to the 1980s. This trend was reversed during the last two decades.

Molecular Markers of Biomass Burning in Arctic Aerosols

Biomass burning is one of the most important sources of organic matter in the atmosphere as it affects the absorption and scattering of solar radiation, creates cloud condensation nuclei and possibly influences ice and snow albedo. Here we created and validated an analytical method using HPLC/(-)-ESI-MS/MS to determine phenolic compounds (PCLCs): vanillic acid, isovanillic acid, homovanillic acid, syringic acid, syringaldehyde, ferulic acid, p-coumaric acid, and coniferyl aldehyde at trace levels in particulate matter. We analyzed eighteen high-volume air samples from Ny Ålesund (Svalbard) collected during the boreal spring and summer of 2010. Biomass burning molecules including PCLCs (<0.49 μm, mean atmospheric concentration 6 pg m(-3)), levoglucosan (0.004 to 0.682 ng m(-3)) and acrylamide (32 fg m(-3) to 166 fg m(-3)) were present in the sampled aerosols. Levoglucosan concentrations, an unambiguous cellulose combustion tracer, derived from 2010 Russian fires. PCLCs levels in the Ny Alesund atmosphere in different size fractions reflected both long-range transport linked to biomass burning and a terrigenous local source.

Determination of Fe2+ and Fe3+ species by FIA-CRC-ICP-MS in Antarctic ice samples

Iron is an element of great interest due to its role in primary production and in oceanic carbon cycle regulation, such that past changes in iron deposition may have influenced oceanic sequestration of atmospheric CO2 on millennial time scales. The behavior of iron in biological and environmental contexts depends strongly on its oxidation state. Solubility in water and the capacity to form complexes are just two important characteristics that are species dependent. Distinguishing between the two iron species, Fe(II) and Fe(III), is necessary to evaluate bioavailability, as Fe(II) is more soluble and therefore more readily available for phytoplankton uptake and growth. Here, we present a novel analytical method for iron speciation analysis using Collision Reaction Cell-Inductively Coupled Plasma-Mass Spectrometry (CRC-ICP-MS) and apply it to ice core samples from Talos Dome, Antarctica. The method detection limit is 0.01 ng g−1. A chelating resin, Ni-NTA Superflow, was used to separate the Fe species. At pH 2 the resin is capable of retaining Fe3+ with no retention of Fe2+. After the initial separation, we oxidized the Fe2+ using H2O2, and determined the Fe2+ concentration as the difference between the two measurements. Our preliminary results demonstrate higher Fe2+ concentrations during glacial periods than during interglacial periods. This elevated concentration of Fe2+ suggests that more iron was available for phytoplankton growth during the Last Glacial Maximum, than would be expected from measurements of proxies such as dust mass or total Fe.

Amino acids in Arctic aerosols

Amino acids are significant components of atmospheric aerosols, affecting organic nitrogen input to marine ecosystems, atmospheric radiation balance, and the global water cycle. The wide range of amino acid reactivities suggest that amino acids may serve as markers of atmospheric transport and deposition of particles. Despite this potential, few measurements have been conducted in remote areas to assess amino acid concentrations and potential sources. Polar regions offer a unique opportunity to investigate atmospheric processes and to conduct source apportionment studies of such compounds. In order to better understand the importance of amino acid compounds in the global atmosphere, we determined free amino acids (FAAs) in seventeen size-segregated aerosol samples collected in a polar station in the Svalbard Islands from 19 April until 14 September 2010. We used an HPLC coupled with a tandem mass spectrometer (ESI-MS/MS) to analyze 20 amino acids and quantify compounds at fmol m −3 levels. Mean total FAA concentration was 1070 fmol m −3 where serine and glycine were the most abundant compounds in almost all samples and accounted for 45–60 % of the total amino acid relative abundance. The other eighteen compounds had average concentrations between 0.3 and 98 fmol m −3. The higher amino acid concentrations were present in the ultrafine aerosol fraction (< 0.49 μm) and accounted for the majority of the total amino acid content. Local marine sources dominate the boreal summer amino acid concentrations, with the exception of the regional input from Icelandic volcanic emissions.

Legal immigrants: invasion of alien microbial communities during winter occurring desert dust storms

BackgroundA critical aspect regarding the global dispersion of pathogenic microorganisms is associated with atmospheric movement of soil particles. Especially, desert dust storms can transport alien microorganisms over continental scales and can deposit them in sensitive sink habitats. In winter 2014, the largest ever recorded Saharan dust event in Italy was efficiently deposited on the Dolomite Alps and was sealed between dust-free snow. This provided us the unique opportunity to overcome difficulties in separating dust associated from “domestic” microbes and thus, to determine with high precision microorganisms transported exclusively by desert dust.ResultsOur metagenomic analysis revealed that sandstorms can move not only fractions but rather large parts of entire microbial communities far away from their area of origin and that this microbiota contains several of the most stress-resistant organisms on Earth, including highly destructive fungal and bacterial pathogens. In particular, we provide first evidence that winter-occurring dust depositions can favor a rapid microbial contamination of sensitive sink habitats after snowmelt.ConclusionsAirborne microbial depositions accompanying extreme meteorological events represent a realistic threat for ecosystem and public health. Therefore, monitoring the spread and persistence of storm-travelling alien microbes is a priority while considering future trajectories of climatic anomalies as well as anthropogenically driven changes in land use in the source regions.

Canadian Arctic sea ice reconstructed from bromine in the Greenland NEEM ice core

Reconstructing the past variability of Arctic sea ice provides an essential context for recent multi-year sea ice decline, although few quantitative reconstructions cover the Holocene period prior to the earliest historical records 1,200 years ago. Photochemical recycling of bromine is observed over first-year, or seasonal, sea ice in so-called “bromine explosions” and we employ a 1-D chemistry transport model to quantify processes of bromine enrichment over first-year sea ice and depositional transport over multi-year sea ice and land ice. We report bromine enrichment in the Northwest Greenland Eemian NEEM ice core since the end of the Eemian interglacial 120,000 years ago, finding the maximum extension of first-year sea ice occurred approximately 9,000 years ago during the Holocene climate optimum, when Greenland temperatures were 2 to 3 °C above present values. First-year sea ice extent was lowest during the glacial stadials suggesting complete coverage of the Arctic Ocean by multi-year sea ice. These findings demonstrate a clear relationship between temperature and first-year sea ice extent in the Arctic and suggest multi-year sea ice will continue to decline as polar amplification drives Arctic temperatures beyond the 2 °C global average warming target of the recent COP21 Paris climate agreement.

DISCOVERY OF COLD ICE IN A NEW DRILLING SITE IN THE EASTERN EUROPEAN ALPS

During autumn 2011 we extracted the first ice cores drilled to bedrock in the eastern European Alps from a new drilling site on the glacier Alto dell’Ortles (3859 m, South Tyrol, Italy). Direct ice core observations and englacial temperature measurements provide evidence of the concomitant presence of shallow temperate firn and deep cold ice layers (ice below the pressure melting point). To the best of our knowledge, this is the first cold ice observed within a glacier of the eastern European Alps. These ice layers probably represent a unique remnant from the colder climate occurring before ~1980 AD. We conclude that the glacier Alto dell’Ortles is now changing from a cold to a temperate state. The occurrence of cold ice layers in this glacier enhances the probability that a climatic and environmental record is fully preserved in the recovered ice cores.

The Alps in the age of the Anthropocene: the impact of human activities on the cryosphere recorded in the Colle Gnifetti glacier

The evaluation of the impact of anthropogenic activities on mountain areas is an important task, because they represent the last remaining natural and pristine environments in highly industrialized continental regions. The deposition of ubiquitous, persistent and toxic organic pollutants in high-altitude sites can potentially affect the alpine ecosystem, which is often characterized by unique plant and animal communities which are precious in terms of ecological value as well as being fragile and easily spoiled. Records from Alpine ice cores have demonstrated to be among the best tools in paleoenvironmental studies to reconstruct past emissions of heavy metals and persistent organic pollutants. From the comparison of trace species records in the snow and ice with the emission inventories compiled in recent years it is also possible to reconstruct the past trends in the emission of these compounds. This knowledge enables a better environmental management and a more effective planning of the human activities in the light of a new sustainable development and could represent the base of a wide and motivated participation to the creation of the future generations. Here, we summarize the results of the geochemical analysis of the Colle Gnifetti firn/ice core, in the Monte Rosa group (NW European Alps).

Water-soluble trace, rare earth elements and organic compounds in Arctic aerosol

We investigated the elemental composition and water-soluble-organic compounds (WSOC) present in size-segregated airborne particulate matter to better understand: (1) the distribution of the water-soluble fraction of trace elements (TE), rare earth elements (REE) and WSOCs among different particulate sizes, and (2) the transport processes of aerosol towards the Arctic zone. Samples were collected at Ny-Alesund in the Svalbard Islands (78°55′07″N, 11°53′30″E) from 19 April to 14 September 2010. Water-soluble TE and REE were measured with the aim of recognising reliable tracers of specific sources, which may prove crucial in cost-effective strategies of air pollution control. The TE and REE content, especially in the finest fractions of aerosols in remote areas, is primarily due to long-range transport. It gives valuable information on the global circulation and on the contribution of human activities to aerosol composition (Birmili et al. in Environ Sci Technol 40:1144–1153, 2006; Fernández-Espinosa et al. in Atmos Environ 38:873–886, 2004; Song et al. in Atmos Environ 35:5277–5286, 2001). On the same samples, we also determined water-soluble organic tracers as specific source indicators: levoglucosan and methoxyphenols from biomass burning, acrylamide from anthropogenic origin and amino acids from primary production. These results were discussed in previous papers (Scalabrin et al. in Atmos Chem Phys 12:10453–10463, 2012; Zangrando et al. in Environ Sci Technol 47:8565–8574, 2013).

Acrylamide determination in atmospheric particulate matter by high-performance liquid chromatography/electrospray ionisation tandem mass spectrometry

A method has been developed for the determination of acrylamide at the picogram per cubic metre level in particulate-phase outdoor aerosol using high-performance liquid chromatography with triple quadrupole tandem mass spectrometric detection. Acrylamide was identified by positive ion electrospray mass spectrometry using m/z 72.00/54.90 as monitoring ion transition. The limit of detection, defined as three times the standard deviation of the procedural blanks, was 0.4 pg m−3 (173 pg absolute amount injected); the repeatability was 8% (evaluated as the relative standard deviation of five consecutive measurements on cleaned quartz fibre filters of acrylamide standard spikes) and the recovery was 52 ± 4%. The accuracy of the method (evaluated as relative error) has been estimated to be −2%. This methodology was used to determine acrylamide concentrations in particulate-phase outdoor aerosol in the Venice Lagoon with concentrations ranging between 0.4 and 12.9 pg m−3 with an average value of 3.1 pg m−3.