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High latitude regions are warming faster than other areas due to reduction of snow cover, sea ice loss, 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 six-year time-series (2010–2016) of physical parameters and particles 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 of ocean and air temperatures. The overarching goal of this study was to continuous monitoring the inner fjord particle sinking and to understand to what extent the temporal evolution of particulate fluxes were 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-silicoclastic and autochthonous marine input. The glacier releasing sediments into the fjord resulted to be 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 maxima in May–June while the land-derived fluxes exhibited a 1–2 months lag consistent with the maximum air temperature and glacier melting. The inter-annual time-weighted total mass fluxes varied two-order of magnitudes 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 in respect to the enhanced release of glacier-derived material. [ABSTRACT FROM AUTHOR]

Major and trace metal concentrations were determined in western Adriatic sediment cores. Based on sediment chronology, the earliest anthropogenic influence appeared as a Zn and Pb increase in the Po River prodelta starting from ~ 1914. The increasing contamination signal of these trace metals propagated southward as far as 450 km with a growing delay, taking ~ 10 years to reach the south Adriatic Sea. Although greater inventories of excess trace metals in the northern sector pointed to the influence of the intense human activities in the Po River drainage basin and Venice lagoon system, we observed a reduction of excess trace metals from mid-1980s, related to the implementation of stricter environmental regulations on chemical wastewaters. In contrast, an increase in trace metal accumulation in surficial sediment from the 2000s in front of the cities of Ancona and Bari suggested a recent local input of trace metals, probably due to harbor activities. [ABSTRACT FROM AUTHOR]

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

Abstract: Thirty-three surface sediment samples from cross-shelf transects on the northern Adriatic shelf were collected in December 2000, soon after a 100-yr flood of the Po River, in order to determine the distribution of organic carbon (OC) along the main sediment dispersal system. To evaluate the temporal variability, stations were re-occupied eight times at seasonal intervals until June 2003. Downcore sediment profiles from two sites characterized by high flood deposit thicknesses were also examined to assess the OC variability within the flood layer. In December 2000, the highest contents of OC (up to 1.24wt%) were measured in front of the main distributary mouths (Pila, Tolle and Gnocca-Goro) where the greatest thicknesses of the flood deposit were recorded. However, the influence of the Po di Gnocca-Goro sediment supply on the OC surface distribution declined after ∼1.5 years from the fall-2000 river flood, probably because these mouths are less active when the water discharge is lower. The δ13C of organic matter was used to trace the dispersal of fluvial OC on the continental shelf. The δ13C values ranged from −25.9‰ to −23.1‰. The fraction of fluvially derived organic particles decreased with increasing water depth according to a radial dispersal pattern around the Po River delta. This pattern persisted in all cruises. δ13C values increased progressively until April 2002, suggesting an increasing marine contribution to the OC content but decreased again following a second minor flood event in November 2002. The molar C/N ratio was on average 10.0±1.6, with slightly lower values in southern and central areas. Assuming contributions from three OC end-members (terrestrial, riverine and marine), a mixing model based on δ13C and the ratio of N to C (statistically more robust than C/N; Goñi, M.A., Teixeir, M.J., Perkley, D.W., 2003. Sources and distribution of organic matter in a river-dominated estuary (Winyah Bay, SC, USA). Estuarine, Coastal and Shelf Science 57, 1023–1048) was applied in order to quantitatively assess the OC sources for Po shelf sediments. δ13C is significantly and positively correlated with the marine OC fraction. The terrestrial fraction is inversely correlated with N/C, while the riverine fraction is positively correlated with N/C. The terrestrial OC source was the most abundant end-member (>70%) showing only little temporal variability regardless of the Po River water discharge. Temporal and spatial changes in OC composition suggest that: (a) the Po River prodelta is always dominated from terrestrial OC input; (b) the Po della Pila supplies most terrestrial OC, whilst other tributaries (e.g., Po di Gnocca-Goro) are secondary sources. However, these mouths are as important as the Po della Pila in affecting the riverine OC signature; (c) offshore, biological primary production raises the marine OC contribution. At two sites on the Po River prodelta, the 2000-flood deposit shows slight but consistent compositional changes of organic matter (N/C and δ13C) which can help to recognize other flood events in the sedimentary record. The OC budget for the 2000-flood deposit accounts for a terrestrial+riverine OC supply of 68–162Gg (109 g) against an OC deposition of 106–162Gg (excluding the marine fraction), which implies a rapid and efficient sedimentation of the flood material, and scarce or negligible export out the study area. Flood events may thus enhance terrestrial carbon burial, whereas marine carbon arrives more slowly and may be largely mineralized at the sediment–water interface. [Copyright &y& Elsevier]

Spatial patterns of major (Al, Fe and Ti) and trace metals (Cu, Cr, Mn, Ni, Pb and Zn) measured in surficial sediments collected within the Late-Holocene mud-wedge in the western Adriatic Sea were analyzed to elucidate their sources, transport and mass budgets. Distributions of sedimentary trace metals, their fluvial inputs and accumulation loads reveal along-shore transport towards the southern Adriatic. Pb and to a lower extent Zn accumulation loads over time decreased significantly since 1988 in the North Adriatic, consistently with the implementation of regulations in the Western Europe, whereas Zn accumulation in the Po River prodelta remained unchanged since 1995. The Po River fluvial inputs accounted for half of Cr, Ni, Pb and Zn of the fluvial inputs into the western Adriatic Sea, contributing for the delivery of important amounts of Cr and Ni into the sediments, probably related to the natural occurrence of ultramafic rocks in the North sector. Collectively, ~ 30% of trace metal fluvial inputs discharged into the North sector are exported to the Central and South sectors. The Po River acts as both a bypass and an accumulation zone. In contrast, trace metal accumulation in the Central sector far exceed trace metal fluvial inputs, which suggested that this area is a preferential sink for particle-reactive river-borne material from the North Adriatic. The North sector shows moderate enrichment of Zn and Pb mainly related to the Po River influence. The anthropogenic fraction of Pb shows a large drop of ~ 30% from the North sector southwards, whereas Zn proportions remain fairly the same up to the Central sector only decreasing in the South sector. [ABSTRACT FROM AUTHOR]

The near-bottom nepheloid layer in the western margin of the Southern Adriatic Sea was monitored for 8-years by measurements acquired at two mooring sites. The two moorings, equipped with CTD probes and ADCPs, are located in the Bari Canyon and in an open slope sector along the Southern Adriatic Margin. These regions are of interest because affected by episodic dense shelf water cascading events whose dynamic has direct implications on deepwater morpho-dynamic, biogeochemical cycles and trophic networks. In this work, the sedimentation flux and its interdecadal dynamic is analysed examining in detail the sedimentary processes triggered by dense water flow through the analysis of the echo records of ADCPs. The integration of hydrodynamic, turbidity and particle grain-size data provided estimates of the sediment flux, separating phases when the flow actively erodes the seabed from phases when particles are transported to the mooring location through density flows. The frequency and velocity of dense-water cascading currents vary in time and space reflecting the capacity of sediment transport. Data analysis demonstrated that the hydrodynamic event that mostly accounts for sediment transfer to the deep basin is represented by current pulses induced by the passage of dense waters. The average annual sediment flux has been quantified and the Bari canyon shows transport more than five time larger than in the open slope sector, confirming that the canyon is the dominant pathway of sediment transfer to the deep basin. In contrast, in the open slope, albeit a minor lateral sediment advection, is impacted by currents that are able to trigger intense resuspension of seabed sediments, which can contribute over 80% of the total solid load. This study allows unravelling the role of cascading in the sediment resuspension and transport processes and is essential to support deciphering the sedimentary records in the study area. The long temporal extent of the dataset used for quantification provides a reliable contribution to the Quaternary sediment budget determination. • The integrated approach proposed in the study made it possible to determine sediment flux during dense water cascade events. • This study allows unravelling the role of cascading in the sediment resuspension and transport processes • The characterization of short-lived events can improve the high-resolution interpretation of the stratigraphic records. • The large temporal extension of the dataset used provides a reliable contribution to the Quaternary sediment budget [ABSTRACT FROM AUTHOR]

The sources and depositional history of polycyclic aromatic hydrocarbons (PAHs) and organochlorine compounds (OCs) over the last century were investigated in sediment cores from the North Adriatic Sea (Po River prodelta) and the South-Western Adriatic Margin (SWAM). Contaminant concentrations were higher in the Po River prodelta. ∑ 16 PAHs ranged from 193 to 533 ng g−1, ∑ 5 PCBs ranged from 0.9 to 5.2 ng g−1 and ∑DDTs (p,p′- DDD + p,p′- DDE) ranged from 0.1 to 2.5 ng g−1. In the SWAM, ∑PAHs ranged from 11 to 74 ng g−1 while ∑PCB and ∑DDT concentrations were close to the MQL. Accordingly, contaminant fluxes were much higher in the northern (mean values of 152 ± 31 ng cm2 y−1 and 0.70 ± 0.35 ng cm2 y−1 for PAHs and OCs, respectively) than in the southern Adriatic (2.62 ± 0.9 ng cm2 y−1 and 0.03 ± 0.02 ng cm2 y−1 for PAHs and OCs, respectively). The historical deposition of PAHs seemed to be influenced by the historical socioeconomic development and by changes in the composition of fossil fuel consumption (from petroleum derivatives to natural gas) in Italy from the end of the 19th century to the present. Similarly, vertical variations in DDT concentrations matched its historical use and consumption in Italy, which started around in the mid-late 1940s to fight typhus during the II World War. Contaminant concentrations detected in sediments does not seem to pose ecotoxicological risk for marine organisms in the Adriatic Sea. • Unprecedented data of historical deposition of contaminants in the SWAM were assessed. • The first use of DDT in Italy followed the typhus epidemics during the II World War. • Concentrations of PCB and DDT decreased after 1980 due to international restrictions. • Historical variation of PAHs seem to follow shifts in energy production in Italy. • The deep Adriatic basin represents as an important repository for contaminants. [ABSTRACT FROM AUTHOR]