Papers by Leonardo Langone
Atmosphere
Elemental carbon (EC), a ubiquitous component of fine atmospheric aerosol derived from incomplete... more Elemental carbon (EC), a ubiquitous component of fine atmospheric aerosol derived from incomplete combustion, is an important player for both climate change and air quality deterioration. Several policy measures have been implemented over the last decades to reduce EC emissions from anthropogenic sources, but still, long-term EC measurements to verify the efficacy of such measurements are limited. In this study, we analyze the concentration of EC suspended in fog water samples, collected over the period 1997–2016 in a rural background site of the southern Po Valley. The comparison between EC in fog water and EC atmospheric aerosol concentration measured since 2012 allowed us to reconstruct EC atmospheric concentration from fog water chemical composition dating back to 1997. The results agree with the EC atmospheric observations performed at the European Monitoring and Evaluation Program (EMEP) station of Ispra in the northern part of the Po Valley since 2002, and confirm that the Po...
Biogeosciences
High-latitude regions are warming faster than other areas due to reduction of snow cover and sea ... more High-latitude regions are warming faster than other areas due to reduction of snow cover and sea ice loss and changes in atmospheric and ocean circulation. The combination of these processes, collectively known as polar amplification, provides an extraordinary opportunity to document the ongoing thermal destabilisation of the terrestrial cryosphere and the release of land-derived material into the aquatic environment. This study presents a 6-year time series (2010-2016) of physical parameters and particle fluxes collected by an oceanographic mooring in Kongsfjorden (Spitsbergen, Svalbard). In recent decades, Kongsfjorden has been experiencing rapid loss of sea ice coverage and retreat of local glaciers as a result of the progressive increase in ocean and air temperatures. The overarching goal of this study was to continuously monitor the inner fjord particle sinking and to understand to what extent the temporal evolution of particulate fluxes was linked to the progressive changes in both Atlantic and freshwater input. Our data show high peaks of settling particles during warm seasons, in terms of both organic and inorganic matter. The different sources of suspended particles were described as a mixing of glacier carbonate, glacier siliciclastic and autochthonous marine input. The glacier releasing sediments into the fjord was the predominant source, while the sediment input by rivers was reduced at the mooring site. Our time series showed that the seasonal sunlight exerted first-order control on the particulate fluxes in the inner fjord. The marine fraction peaked when the solar radiation was at a maximum in May-June while the land-derived fluxes exhibited a 1-2-month lag consistent with the maximum air temperature and glacier melting. The inter-annual time-weighted total mass fluxes varied by 2 orders of magnitude over time, with relatively higher values in 2011, 2013, and 2015. Our results suggest that the land-derived input will remarkably increase over time in a warming scenario. Further studies are therefore needed to understand the future response of the Kongsfjorden ecosystem alterations with respect to the enhanced release of glacier-derived material.
Environmental Pollution, 2016
The spatial distributions and fates of selected legacy and emerging compounds were investigated a... more The spatial distributions and fates of selected legacy and emerging compounds were investigated and compared in surface sediments sampled along the Adriatic mud-wedge and in deep-sea regions from the southern Adriatic basin. Results indicated that the concentrations of legacy contaminants (PAHs, PCBs and DDTs) and emerging contaminants (tonalide, galaxolide, EHMC, octocrylene, BP3 and NP) ranged from 0.1 to 572 ng g(-1) and from <LOD to 40.7 ng g(-1), respectively. In general, higher concentrations and estimated burdens were detected in the northern Adriatic, highlighting the importance of the Po River as the major contributor for the inputs of legacy and emerging contaminants to sediments in the Adriatic Sea. Nevertheless, the prevalence of some UV filters and fragrances in the central and southern Adriatic indicates that the proximity to tourist areas and WWTPs discharges seems to affect the distribution of those compounds. The accumulation of contaminants in the deep-sea areas supports the inference that this region may act as an important repository for contaminants within the Adriatic Sea. Estimated annual contaminant accumulation reveals that both, legacy and emerging contaminants accumulate preferentially in the northern Adriatic (40-60% of the total annual contaminant accumulation), where the presence of legacy, and to a lesser extent emerging contaminants, are likely to pose an immediate or long-term hazard to resident biota.
Scientific reports, Jul 14, 2016
The Eastern Mediterranean Transient (EMT) occurred in the Aegean Sea from 1988 to 1995 and is the... more The Eastern Mediterranean Transient (EMT) occurred in the Aegean Sea from 1988 to 1995 and is the most significant intermediate-to-deep Mediterranean overturning perturbation reported by instrumental records. The EMT was likely caused by accumulation of high salinity waters in the Levantine and enhanced heat loss in the Aegean Sea, coupled with surface water freshening in the Sicily Channel. It is still unknown whether similar transients occurred in the past and, if so, what their forcing processes were. In this study, sediments from the Sicily Channel document surface water freshening (SCFR) at 1910 ± 12, 1812 ± 18, 1725 ± 25 and 1580 ± 30 CE. A regional ocean hindcast links SCFR to enhanced deep-water production and in turn to strengthened Mediterranean thermohaline circulation. Independent evidence collected in the Aegean Sea supports this reconstruction, showing that enhanced bottom water ventilation in the Eastern Mediterranean was associated with each SCFR event. Comparison be...
Atmos Environ, 2010
Continuous measurements of the CO 2 concentration were repeatedly carried out from 1996 to 2007 b... more Continuous measurements of the CO 2 concentration were repeatedly carried out from 1996 to 2007 between Italy and New Zealand by means of a Siemens Ultramat 5E analyzer assembled for shipboard use. Along the ship routes discrete air samples were collected from 1998 to 2005 using four-litre Pyrex flasks. The d 13 C of the CO 2 from the flask air samples was measured according to well-established techniques. The decadal changes of these two variables can now be evaluated from these results. Large variations of the CO 2 concentration were normally recorded in the Mediterranean and the Red Sea. Completely different trends of the CO 2 concentration were observed in the Red Sea (30 N to about 13 N) between 2007 (a marked southward decrease) and 2005 and 2003 when a marked southward increase is apparent, at least between 23 and 13 N. A further difference among different expeditions is related to the decrease or increase of the CO 2 concentration in the Gulf of Aden. The backward trajectories of the air masses help to explain, at least partially, these differences. In the Indian Ocean and Southern Ocean a decrease of a few ppmv of the CO 2 concentration takes place from Cape Guardafui (Northern Somaliland) to southern New Zealand, particularly during 2005 and 2007. The yearly rate of increase of the CO 2 concentration between 1996 and 2007 for the Indian Ocean is of about 1.9 ppmv yr À1 , in excellent agreement with the NOAA/CMDL measurements carried out during the same period at Mahé Isld. (Indian Ocean) and Cape Grim (Tasmania). The d 13 C results obtained from the CO 2 of flask samples collected in the Mediterranean show the effect of anthropogenic emissions, though this is considerably smaller than expected. This inconsistency may be related to the large terrestrial biospheric sink of CO 2 in the Northern Hemisphere. The results obtained from the Red Sea are quite variable through time and space, particularly in its southern section; their interpretation is not easy. The Indian Ocean and the Southern Ocean show rather homogeneous d 13 C results even though a variable carbon isotope shift can be calculated from period/cruise to period/cruise. In the case of the Indian Ocean the mean d 13 C value from the flask air samples collected in 2005 is À8.29& and the calculated rate of the carbon isotope shift between 1998 and 2005 is À0.034& yr À1 , considerably larger than that calculated at the closest NOAA station (Mahé Isld.) of À0.026& yr À1. This discrepancy may be, at least partially, caused by the small number of measurements carried out at sea. However, the atmosphere over the Indian Ocean is less affected by anthropogenic emissions than in other areas.
Atmos Environ, 2010
Continuous measurements of the CO 2 concentration were repeatedly carried out from 1996 to 2007 b... more Continuous measurements of the CO 2 concentration were repeatedly carried out from 1996 to 2007 between Italy and New Zealand by means of a Siemens Ultramat 5E analyzer assembled for shipboard use. Along the ship routes discrete air samples were collected from 1998 to 2005 using four-litre Pyrex flasks. The d 13 C of the CO 2 from the flask air samples was measured according to well-established techniques. The decadal changes of these two variables can now be evaluated from these results. Large variations of the CO 2 concentration were normally recorded in the Mediterranean and the Red Sea. Completely different trends of the CO 2 concentration were observed in the Red Sea (30 N to about 13 N) between 2007 (a marked southward decrease) and 2005 and 2003 when a marked southward increase is apparent, at least between 23 and 13 N. A further difference among different expeditions is related to the decrease or increase of the CO 2 concentration in the Gulf of Aden. The backward trajectories of the air masses help to explain, at least partially, these differences. In the Indian Ocean and Southern Ocean a decrease of a few ppmv of the CO 2 concentration takes place from Cape Guardafui (Northern Somaliland) to southern New Zealand, particularly during 2005 and 2007. The yearly rate of increase of the CO 2 concentration between 1996 and 2007 for the Indian Ocean is of about 1.9 ppmv yr À1 , in excellent agreement with the NOAA/CMDL measurements carried out during the same period at Mahé Isld. (Indian Ocean) and Cape Grim (Tasmania). The d 13 C results obtained from the CO 2 of flask samples collected in the Mediterranean show the effect of anthropogenic emissions, though this is considerably smaller than expected. This inconsistency may be related to the large terrestrial biospheric sink of CO 2 in the Northern Hemisphere. The results obtained from the Red Sea are quite variable through time and space, particularly in its southern section; their interpretation is not easy. The Indian Ocean and the Southern Ocean show rather homogeneous d 13 C results even though a variable carbon isotope shift can be calculated from period/cruise to period/cruise. In the case of the Indian Ocean the mean d 13 C value from the flask air samples collected in 2005 is À8.29& and the calculated rate of the carbon isotope shift between 1998 and 2005 is À0.034& yr À1 , considerably larger than that calculated at the closest NOAA station (Mahé Isld.) of À0.026& yr À1. This discrepancy may be, at least partially, caused by the small number of measurements carried out at sea. However, the atmosphere over the Indian Ocean is less affected by anthropogenic emissions than in other areas.
Marine Geology, Nov 1, 2005
In October 2000, a major flood event of the Po River occurred. The resulting seabed deposit was i... more In October 2000, a major flood event of the Po River occurred. The resulting seabed deposit was initially sampled in December 2000, and most sites were reoccupied on subsequent cruises over a 3-yr period. Using the maximum penetration depth of the short-lived radioisotope 7 Be (half-life 53.3 d), the flood deposit was found to be up to 15 cm thick. Individual depocenters of thick strata were located immediately adjacent to the distributaries at the river mouth in relatively shallow water (b 30 m). These flood deposit thicknesses are minimum estimates because the depth of 234 Th (half-life 24.1 d) exceeds that of 7 Be in physically stratified flood sediment, indicating that the first sediment deposited during the flood event likely originated from the river channel. 30-55% of the estimated sediment load delivered to the shelf during the flood event can be accounted for using 7 Be penetration depths. Seasonal deposition also can be quantified using 7 Be, after removing the effects of biological mixing. Seasonal deposition rates are a maximum of 6 cm yr À 1 near the Pila distributary, decreasing to 2 cm yr À 1 in the southern portions of the dispersal system.
Chemistry and Ecology, Jun 1, 2008
Mg/Ca ratios in living specimens of the planktonic foraminifer Neogloboquadrina pachyderma (sin.)... more Mg/Ca ratios in living specimens of the planktonic foraminifer Neogloboquadrina pachyderma (sin.) have been investigated using Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) and ultracleaning procedures on 'bulk' foraminifera followed by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and Inductively Coupled Plasma Atomic Emission Spectrophotometry (ICP-AES) analysis. Plankton tows were taken in the upper 250 m of the water column at different sites in the Ross Sea and at the Polar Front of the Pacific Ocean during 6 austral summers. We found high values of Mg/Ca ratios in N. pachyderma (s.) not previously reported in the literature. Our data suggest that at least two factors influence the results: (1) the presence of some protoplasm in the test of living specimens, which seems to control the actual Mg concentration and (2) the morphotype of the analysed specimens in term of test thickness.
The Science of the total environment, Jan 15, 2016
Sources, historical trends and inventories of polychlorinated biphenyls (PCBs) were investigated ... more Sources, historical trends and inventories of polychlorinated biphenyls (PCBs) were investigated in sediments collected in five transects along the north-south axis of the western Adriatic Sea. The concentration of total PCBs (∑28 PCBs) ranged from <LOD (limit of detection) to 9.0ngg(-1) in the sediment cores and between 0.1 and 2.2ngg(-1) in recent sediments. Chronological records of PCB concentrations displayed a common pattern with historical PCB production and use, with the maximum peak values detected between the 1960s and the 1980s. Sediments deposited within the last two decades presented a ~40% to ~80% PCB reduction in comparison to the peak levels, reflecting the ban on PCB production and use since the late 1970s. PCB levels along with the presence of high-chlorinated congeners decreased southwards, indicating the Po River as the major source of PCBs in the western Adriatic Sea. This is further corroborated by the estimated inventories of PCBs, which were ~4-7 times high...
Journal De Physique Iv, 2003
ABSTRACT A mooring was deployed in the southem Adriatic basin (1030 m depth) between April 1994 a... more ABSTRACT A mooring was deployed in the southem Adriatic basin (1030 m depth) between April 1994 and October 1995. The mooring was equipped with two time-series sediment traps placed at 500 and 35 m above the bottom, respectively. Mass fluxes at both depths are characterised by high variability (26-1577 mg cm$^{-2}$ y$^{-1}$), without a clear seasonal trend. Particulate $^{210}$Pb activities vary within a relatively limited range of values (13-74 dpm g$^{-1}$) and do not show any evident relationship with water depth. Activities are higher in winter. The correlation between $^{210}$Pb activity and organic matter in the upper water column suggests that $^{210}$Pb scavenging may be controlled by carbon cycle. On the contrary, at the near-bottom trap $^{210}$Pb activity seems to be driven by the amount of particles, their residence time in the water column and the contribution of lateral advection. The mass balances of both particulate matter and $^{210}$Pb require a very significant lateral input between the lower trap and the sea bottom. This flux is mainly consisting of resuspended sediment and seems to be episodic.
ABSTRACT The amount of high quality measurements of the carbonate system properties trough the wh... more ABSTRACT The amount of high quality measurements of the carbonate system properties trough the whole Mediterranean Sea is so scarce that was almost impossible to have any precise idea of their distribution until very recently (Ylmaz et al., 36th CIEMS Workshop Monographs 2008). Actually, only in the last decade oceanographic campaigns including such parameters have been carried out(2001-2011) and provided long west-east section trough the Mediterranean basin (Touratier &amp; Goyet, 2011; Schneider et al., 2010) pointing out west-east gradients. For what concerns the latitudinal variability of carbonate system (from the North to the South) in the central Mediterranean Sea (Adriatic and Ionian basins,it is even more poorly known although the occurrence of key processes as ocean acidification, river runoff, dense water formation and high primary production, especially in the Adriatic basin, can produce latitudinal gradients. T he main results of two cruises (in 2008) along the Adriatic and the Ionian basins are presented. Two key properties (pHT and AT) have been measured and the derived carbonate system properties (TCO2, fCO2, CO3=, HCO3-, ?Ar, ΩCa ) calculated. The main objectives of this poster are (1) to draw and comment on their distributions (pHT in particular) in the light of other properties like salinity, temperature and dissolved oxygen, (2) relate them to the major driving processes and (3) compare surface waters properties (the average in situ values of pHT, TCO2, CO3=, ΩCa and ?Ar ) to those of other oceanic regions (Feely et al.,2009). Concerning 1st objective, Adriatic Dense Waters have been observed in winter and their carbonate system properties have been characterized. Concerning 2nd one, both thermal and biological controls are driving the inorganic carbon chemistry. Regarding 3rd one, the comparison between surface waters in the central Mediterranean and other oceanic regions points out that central Med contains the highest amount of dissolved inorganic carbon (2340.1 ± 38.0 µm/Kg) with low carbonate ion concentration (218.0 ± 9.0 µm/Kg), in particular at North(in the Adriatic Sea) in winter (when biological activity is absent and river runoff is low and confined to the western slope). This suggests that Mediterranean Sea is really one of the most impacted by OA and indicates that the region is an important place where studying the marine inorganic carbon system and its response to climate change and OA, as CO2 fluxes are potentially high (being sorrounded by industrialzed regions)and renewal of water masses is faster than in oceanic regions.
Atmos Environ, 2011
During summer 2007, two survey cruises covered large sections of both western and eastern Mediter... more During summer 2007, two survey cruises covered large sections of both western and eastern Mediterranean basins. Atmospheric CO 2 concentrations were measured with a Siemens Ultramat 5E analyser on both outward and return voyages, and 48 discrete air samples were collected with evacuated Pyrex flasks. The delta 13 C values of the CO 2 from the flask air samples were
ABSTRACT Sediment supply to the Adriatic Sea is dominated by the Po and Apennine Rivers in the no... more ABSTRACT Sediment supply to the Adriatic Sea is dominated by the Po and Apennine Rivers in the northern and southern regions, respectively. Recent investigations have revealed that processes impacting sedimentation in this area are active on a variety of time-scales, ranging from events (e.g., floods) to seasonal and decadal variations. In the northern region, flooding of the Po River is common, and a 100-year flood event occurred in October 2000. Using 7Be (half-life 53.3 days) as a tracer of flood sediment, the deposit was found to be up to 15-cm thick. However, the depth of 234Th (half-life 24.1 days) exceeds 7Be in cores of the flood deposit, indicating that thicknesses derived from 7Be are minimum estimates and that the first sediment deposited during the flood event likely originated from the river channel. The location of the flood deposit immediately adjacent to the distributary channels at the river mouth can be predicted considering the relatively low-energy physical oceanographic conditions during the time of emplacement. Near the Po River Delta, sediment from flood events contributes significantly to longer-term (100-year) sediment accumulation. The signature of flood layers is observed in radiochemical (low 210Pb activities; half-life 22.3 years) and textural (fine grain size) profiles, which lead to accumulation rates &gt;2 cm/y. Southward, the character of sediment accumulation transitions to steady state, reflecting the decreased impact of event sedimentation, and accumulation rates decrease to levels near and below 1 cm/y in the southern portion of the Po River dispersal system. Sedimentation near the Apennine Rivers is even more strongly impacted by anthropogenic activities (dam construction), which increased after the second World War. These activities have resulted in a reduction of sediment accumulation in the area, evidenced by changes in 210Pb profiles. Across-shelf accumulation rates reach a maximum on the foreset of a shelf clinoform and are ˜~1 cm/y.
Continental shelves play an important role in the global carbon cycle because they represent the ... more Continental shelves play an important role in the global carbon cycle because they represent the largest modern repository of particulate organic carbon. However, recent studies indicate that the role of shelves as sinks for Corg is still poorly known in details, suggesting that more understanding of sedimentary processes affecting the distribution and preservation of organic matter on the continental shelves
Agu Fall Meeting Abstracts, 2004
Sediment supply to the Adriatic Sea is dominated by the Po and Apennine Rivers in the northern an... more Sediment supply to the Adriatic Sea is dominated by the Po and Apennine Rivers in the northern and southern regions, respectively. The Po River is the largest point source of sediment, delivering 1.5x107 tons annually to the adjacent shelf. Investigations into the pattern of 100-y sediment accumulation using 210Pb (half-life 22.3 y) have revealed that accumulation rates are greatest in
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Papers by Leonardo Langone