Centro B Segre

Rome, Italy

Centro B Segre

Rome, Italy
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Gabrielli P.,Ohio State University | Hardy D.R.,University of Massachusetts Amherst | Kehrwald N.,University of Venice | Davis M.,Ohio State University | And 6 more authors.
Quaternary Science Reviews | Year: 2014

Ice fields on Kilimanjaro (5895m a.s.l., Tanzania) are retreating and 85% of the ice cover has been lost since 1912. The degree to which this recession is exceptional during the Holocene is uncertain, as age control of the entire ice stratigraphy exists only for the very shallow and very bottom ice of the Northern Ice Field. This empirical evidence suggests that the Kilimanjaro ice cover may be a persistent Holocene feature, while a model based on maximum possible extent and a constant shrinkage rate of the summit glaciers suggests a cyclic decay time on the order of one to two centuries. Today the mass balance of these ice fields is negative and no persistent ice accumulation zones are observed over multiannual scales. The expanding deglaciated area within the Kilimanjaro caldera should act as an increasingly larger and productive source of volcanic-origin aeolian dust that is quickly deposited onto the surface of the adjacent ice fields, particularly in the seasonal absence of caldera snow cover. Variations in the local dust influx may directly influence albedo and the energy balance of these ice fields. Investigating the characteristics of insoluble material entrapped in the ice remnants of Kilimanjaro can thus provide insights into the extent of ice and/or continuity of the summit snow cover through time. Here we report the trace element composition linked to the insoluble particles entrapped in Holocene Kilimanjaro ice in the context of the current understanding of the past ice accumulation processes (including solid precipitations and ablation) contributing to build the horizontal caldera ice fields. For this purpose we analysed an ice core drilled to bedrock from the Northern Ice Field thought to span the late Holocene (2200 BC-1950 AD). The ultra low trace element concentrations recorded in this Kilimanjaro core are consistent with a generally low volcanic dust source availability (i.e. limited exposure of the deglaciated area in the caldera) and fairly continuous ice accumulation during the late Holocene. In contrast, the maximum concentrations for most of the trace elements recorded in the surface ice section suggest that the current lack of ice accumulation on the Kilimanjaro ice fields is unusual over the last ~4ka. © 2014.

Gabrieli J.,CNR Institute for the Dynamics of Environmental Processes | Barbante C.,CNR Institute for the Dynamics of Environmental Processes | Barbante C.,University of Venice | Barbante C.,Centro B Segre
Rendiconti Lincei | Year: 2014

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). © 2014 Accademia Nazionale dei Lincei.

Vallelonga P.,Copenhagen University | Vallelonga P.,University of Venice | Barbante C.,University of Venice | Barbante C.,Centro B Segre | And 6 more authors.
Climate of the Past | Year: 2013

Atmospheric fluxes of iron (Fe) over the past 200 kyr are reported for the coastal Antarctic Talos Dome ice core, based on acid leachable Fe concentrations. Fluxes of Fe to Talos Dome were consistently greater than those at Dome C, with the greatest difference observed during interglacial climates. We observe different Fe flux trends at Dome C and Talos Dome during the deglaciation and early Holocene, attributed to a combination of deglacial activation of dust sources local to Talos Dome and the reorganization of atmospheric transport pathways with the retreat of the Ross Sea ice shelf. This supports similar findings based on dust particle sizes and fluxes and Rare Earth Element fluxes. We show that Ca and Fe should not be used as quantitative proxies for mineral dust, as they all demonstrate different deglacial trends at Talos Dome and Dome C. Considering that a 20 ppmv decrease in atmospheric CO2 at the coldest part of the last glacial maximum occurs contemporaneously with the period of greatest Fe and dust flux to Antarctica, we confirm that the maximum contribution of aeolian dust deposition to Southern Ocean sequestration of atmospheric CO2 is approximately 20 ppmv. © Author(s) 2013.

Zennaro P.,University of Venice | Zennaro P.,CNR Institute of Neuroscience | Kehrwald N.,University of Venice | McConnell J.R.,Desert Research Institute | And 16 more authors.
Climate of the Past | Year: 2014

Biomass burning is a major source of greenhouse gases and influences regional to global climate. Pre-industrial fire-history records from black carbon, charcoal and other proxies provide baseline estimates of biomass burning at local to global scales spanning millennia, and are thus useful to examine the role of fire in the carbon cycle and climate system. Here we use the specific biomarker levoglucosan together with black carbon and ammonium concentrations from the North Greenland Eemian (NEEM) ice cores (77.49° N, 51.2° W; 2480 m a.s.l) over the past 2000 years to infer changes in boreal fire activity. Increases in boreal fire activity over the periods 1000-1300 CE and decreases during 700-900 CE coincide with high-latitude NH temperature changes. Levoglucosan concentrations in the NEEM ice cores peak between 1500 and 1700 CE, and most levoglucosan spikes coincide with the most extensive central and northern Asian droughts of the past millennium. Many of these multi-annual droughts are caused by Asian monsoon failures, thus suggesting a connection between low- and high-latitude climate processes. North America is a primary source of biomass burning aerosols due to its relative proximity to the Greenland Ice Cap. During major fire events, however, isotopic analyses of dust, back trajectories and links with levoglucosan peaks and regional drought reconstructions suggest that Siberia is also an important source of pyrogenic aerosols to Greenland. © Author(s) 2014.

Scalabrin E.,University of Venice | Zangrando R.,University of Venice | Barbaro E.,University of Venice | Kehrwald N.M.,University of Venice | And 4 more authors.
Atmospheric Chemistry and Physics | Year: 2012

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. © 2012 Author(s).

Zennaro P.,CNR Institute of Neuroscience | Zennaro P.,University of Venice | Kehrwald N.,University of Venice | Marlon J.,Yale University | And 10 more authors.
Geophysical Research Letters | Year: 2015

The timing of initiation of human impacts on the global climate system is actively debated. Anthropogenic effects on the global climate system are evident since the Industrial Revolution, but humans may have altered biomass burning, and hence the climate system, for millennia. We use the specific biomarker levoglucosan to produce the first high-temporal resolution hemispheric reconstruction of Holocene fire emissions inferred from ice core analyses. Levoglucosan recorded in the Greenland North Greenland Eemian ice core significantly increases since the last glacial, resulting in a maximum around ∼2.5 ka and then decreasing until the present. Here we demonstrate that global climate drivers fail to explain late Holocene biomass burning variations and that the levoglucosan maximum centered on ∼2.5 ka may be due to anthropogenic land clearance. © 2015. The Authors.

Roman M.,CNR Institute of Neuroscience | Jitaru P.,Polytechnic Institute of LaSalle Beauvais | Agostini M.,University of Padua | Agostini M.,Methodist Hospital Research Institute | And 8 more authors.
Microchemical Journal | Year: 2012

In this case-control pilot study a recent method based on HPLC hyphenated to ICP-MS was employed for the quantification of serum glutathione peroxidase type 3 (GPx3), seleno-protein P (SelP) and seleno-albumin (SeAlb) in 42 patients with colorectal cancer (CRC) and 20 controls. Patients with early cancer stage (TNM I) showed a significantly higher level of SeAlb (19 ± 3. ng/mL) in respect to both metastatic CRC patients (TNM IV, 16 ± 4. ng/mL) and healthy controls (16 ± 3. ng/mL). Classification models based on logistic regression analysis, classification trees and artificial neural networks were constructed using seleno-proteins concentrations as predictors. Neural networks lead to the best performances, up to 95% of corrected predictions in TNM I vs. controls discrimination. These results suggest a potential association between individual seleno-proteins and CRC progression. Age and radiochemoteraphy were assessed as confounding factors, showing no significant effects. Still, SeAlb level tended to reduce with the age in healthy persons, but did not in CRC patients. Seleno-proteins concentration was also compared with a number of clinical parameters considered as prognostic factors in CRC. Significant Spearman's correlations were revealed between SelP and SeAlb, and presence of peritumoural lymphocytic infiltration (ρ = - 0.57 and ρ = - 0.37, respectively); and SeAlb and degree of cellular differentiation (grading, ρ = - 0.37). This study marks the importance to systematically introduce speciation analysis and multidisciplinary approaches in the investigation of the role of seleno-proteins as a potential combined biomarker for CRC. © 2012 Elsevier B.V.

Spolaor A.,University of Siena | Spolaor A.,University of Venice | Vallelonga P.,Niels Bohr Institute | Gabrieli J.,University of Venice | And 8 more authors.
Analytical and Bioanalytical Chemistry | Year: 2013

Iodine and bromine species participate in key atmospheric reactions including the formation of cloud condensation nuclei and ozone depletion. We present a novel method coupling a high-performance liquid chromatography with ion chromatography and inductively coupled plasma mass spectrometry, which allows the determination of iodine (I) and bromine (Br) species (IO 3 -, I-, Br-, BrO 3 - ) at the picogram-per-gram levels presents in Antarctic ice. Chromatographic separation was achieved using an IONPAC® AS16 Analytical Column with NaOH as eluent. Detection limits for I and Br species were 5 to 9 pg g-1 with an uncertainty of less than 2.5% for all considered species. Inorganic iodine and bromine species have been determined in Antarctic ice core samples, with concentrations close to the detection limits for iodine species, and approximately 150 pg g-1 for Br-. Although iodate (IO 3 - ) is the most abundant iodine species in the atmosphere, only the much rarer iodide (I-) species was present in Antarctic Holocene ice. Bromine was found to be present in Antarctic ice as Br-. © 2012 Springer-Verlag.

Gabrielli P.,Ohio State University | Barbante C.,CNR Institute for the Dynamics of Environmental Processes | Barbante C.,Centro B Segre | Carturan L.,University of Padua | And 14 more authors.
Geografia Fisica e Dinamica Quaternaria | Year: 2012

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.

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