Mercury Content in Central and Southern Adriatic Sea Sediments in Relation to Seafloor Geochemistry and Sedimentology

Mercury contents were determined in surface sediments from the Central and Southern Adriatic Sea to gain insight into the processes, factors, and variables affecting its distribution. Mercury concentration was measured by thermal decomposition amalgamation atomic absorption spectrometry in samples collected by box-corer from Ancona to Santa Maria di Leuca during the CNR-PERTRE cruise (16/9-4/10/2016). Sediments were also evaluated for chemical-physical parameters (pH, Eh), biogeochemical composition (total carbon, inorganic carbon, total organic carbon, organic matter) and grain size. The average mercury concentration in the Adriatic Sea sediment was 0.053 mg/Kg (d.w.), range 0.011–0.12 mg/Kg (d.w.). Mercury content was mainly affected by grain size and organic matter (OM) distribution, whereas anthropic factors exerted a limited influence. Concentrations followed the distribution of sediment types (clay > silt > sand) due to Adriatic Sea hydrodynamics and were well below the regulatory limits in all samples

Determination of mercury in the sediments of the Adriatic Sea in relation to their geochemical and sedimentological characterization

The aim of this research was to investigate the mercury content in the superficial sediments of the Adriatic Sea in relation to the depositional processes present and to the Holocene evolution. To do this, above the analysis of mercury in the surface sediment, were considered the data of the biogeochemical composition (TC, IC, TOC, TN, OM, major and minor elements) and of the sediment granulometry. Surface sediment samples were collected during the PERTRE oceanographic campaign, conducted in September-October 2016 by the ISMAR-CNR institute of Ancona [1]. Altogether 107 samples were collected by box-corer, in an area of the Central Southern Adriatic Sea that goes from the waters in front of Potenza Picena (MC) to those off the coast of Santa Maria di Leuca (LE) (Fig. 1).The granulometry (Fig. 2) and the geochemistry data (Fig. 3) [2], as already partially highlighted above [3], indicate a current silty coarse deposition zone near the coast, an area of mainly fine clayey deposition that extends to the center of the Adriatic in the deepest areas and a coarser (silicatic and carbonatic) outer zone towards the center of the basin in the less profound areas in which the coarse sediments are variously deposited during the last glacial period. For what concerns the mercury [4], values between 0.0106 and 0.123 mg/kg have been found, with an average value of 0.0526 mg/kg. From the surface distribution map of mercury (Fig. 4), a distribution in three bands can be observed, which traces the particle size distribution (Fig. 2) and the geochemistry (Fig. 3). Going eastwards there is a coastal strip with low values of mercury, linked to the scarce presence of fine material, with which the metals have a greater affinity, for the removal effected by the wave motion at low depths. This is followed by a central band in correspondence with the main accretion zone of the fine holocene accretion wedge. Finally, at the center of the basin, an external area is encountered in which mercury concentrations decrease due to the reduction of recent Holocene contributions. From this general trend differs the southernmost coastal zone (between Ostuni and Otranto) where mercury values also increase near the coast, such coastal increases could be of probable anthropic origin. Further observations on the distribution of mercury can be inferred from the association with the distribution of the organic substance (Fig. 5) and from the correlation with the PAHs (Fig. 6). In the first case, the highest concentrations of mercury are recorded in sediment samples characterized by higher concentrations of organic substance that also coincide with the higher concentrations of fine material, confirming the high affinity of this element with the two components. In the second case, the highest concentrations of mercury are recorded in sediment samples characterized by higher concentrations of Polycyclic Aromatic Hydrocarbons (PAH) that are found in the southernmost coastal area confirming a possible anthropic origin

Mercury Content in Central and Southern Adriatic Sea Sediments in Relation to Seafloor Geochemistry and Sedimentology

Mercury contents were determined in surface sediments from the Central and Southern Adriatic Sea to gain insight into the processes, factors, and variables affecting its distribution. Mercury concentration was measured by thermal decomposition amalgamation atomic absorption spectrometry in samples collected by box-corer from Ancona to Santa Maria di Leuca during the CNR-PERTRE cruise (16/9-4/10/2016). Sediments were also evaluated for chemical-physical parameters (pH, Eh), biogeochemical composition (total carbon, inorganic carbon, total organic carbon, organic matter) and grain size. The average mercury concentration in the Adriatic Sea sediment was 0.053 mg/Kg (d.w.), range 0.011–0.12 mg/Kg (d.w.). Mercury content was mainly affected by grain size and organic matter (OM) distribution, whereas anthropic factors exerted a limited influence. Concentrations followed the distribution of sediment types (clay > silt > sand) due to Adriatic Sea hydrodynamics and were well below the regulatory limits in all sample

Sensitivity of foraminiferal-based indices to evaluate the ecological quality status of marine coastal benthic systems: A case study of the Gulf of Manfredonia (southern Adriatic Sea)

none10noThis paper aims to compare two foraminiferal based biotic indices generally used to evaluate the ecological quality status (EcoQS): the Foram-AMBI and the Foram Stress Index (FSI). For this purpose, we report the distribution and diversity of living foraminiferal assemblages and the environmental variables from a bathymetric transect in the Southern Adriatic Sea. The two indices agree well with the detected organic enrichment but indicate conflicting EcoQS as the Foram-AMBI detects good environmental conditions, whereas the FSI describes a poor-moderate quality. Many species not assigned (including soft-shelled foraminifera) are to blame for the different results. Also, both foraminiferal-based indices neglect the heavy metal increase encountered in the deepest stations. These findings suggest the need for a more in-depth analysis to improve the ecological status evaluation of marine benthic systems, including other descriptors as chemical pollutants in combination with biotic indices sensitive to organic matter enrichment.noneEleonora Fossile, Anna Sabbatini, Federico Spagnoli, Francesca Caridi, Antonio Dell’Anno, Rocco de Marco, Enrico Dinelli, Elisa Droghini, Mario Tramontana, Alessandra NegriFossile, Eleonora; Sabbatini, Anna; Spagnoli, Federico; Caridi, Francesca; Dell’Anno, Antonio; de Marco, Rocco; Dinelli, Enrico; Droghini, Elisa; Tramontana, Mario; Negri, Alessandr

Determination of mercury in the sediments of the Adriatic sea in relation to their geochemical and sedimentological characterization.

The aim of this research was to investigate the mercury content in the superficial sediments of the Adriatic Sea in relation to the depositional processes present and to the Holocene evolution. To do this, above the analysis of mercury in the surface sediment, were considered the data of the biogeochemical composition (TC, IC, TOC, TN, OM, major and minor elements) and of the sediment granulometry. Surface sediment samples were collected during the PERTRE oceanographic campaign, conducted in September-October 2016 by the ISMAR-CNR institute of Ancona [1]. Altogether 107 samples were collected by box-corer, in an area of the Central Southern Adriatic Sea that goes from the waters in front of Potenza Picena (MC) to those off the coast of Santa Maria di Leuca (LE) (Fig. 1).The granulometry (Fig. 2) and the geochemistry data (Fig. 3) [2], as already partially highlighted above [3], indicate a current silty coarse deposition zone near the coast, an area of mainly fine clayey deposition that extends to the center of the Adriatic in the deepest areas and a coarser (silicatic and carbonatic) outer zone towards the center of the basin in the less profound areas in which the coarse sediments are variously deposited during the last glacial period. For what concerns the mercury [4], values between 0.0106 and 0.123 mg/kg have been found, with an average value of 0.0526 mg/kg. From the surface distribution map of mercury (Fig. 4), a distribution in three bands can be observed, which traces the particle size distribution (Fig. 2) and the geochemistry (Fig. 3). Going eastwards there is a coastal strip with low values of mercury, linked to the scarce presence of fine material, with which the metals have a greater affinity, for the removal effected by the wave motion at low depths. This is followed by a central band in correspondence with the main accretion zone of the fine holocene accretion wedge. Finally, at the center of the basin, an external area is encountered in which mercury concentrations decrease due to the reduction of recent Holocene contributions. From this general trend differs the southernmost coastal zone (between Ostuni and Otranto) where mercury values also increase near the coast, such coastal increases could be of probable anthropic origin. Further observations on the distribution of mercury can be inferred from the association with the distribution of the organic substance (Fig. 5) and from the correlation with the PAHs (Fig. 6). In the first case, the highest concentrations of mercury are recorded in sediment samples characterized by higher concentrations of organic substance that also coincide with the higher concentrations of fine material, confirming the high affinity of this element with the two components. In the second case, the highest concentrations of mercury are recorded in sediment samples characterized by higher concentrations of Polycyclic Aromatic Hydrocarbons (PAH) that are found in the southernmost coastal area confirming a possible anthropic origin

Sensitivity of foraminiferal-based indices to evaluate the ecological quality status of marine coastal benthic systems: A case study of the Gulf of Manfredonia (southern Adriatic Sea)

This paper aims to compare two foraminiferal based biotic indices generally used to evaluate the ecological quality status (EcoQS): the Foram-AMBI and the Foram Stress Index (FSI). For this purpose, we report the dis-tribution and diversity of living foraminiferal assemblages and the environmental variables from a bathymetric transect in the Southern Adriatic Sea. The two indices agree well with the detected organic enrichment but indicate conflicting EcoQS as the Foram-AMBI detects good environmental conditions, whereas the FSI describes a poor-moderate quality. Many species not assigned (including soft-shelled foraminifera) are to blame for the different results. Also, both foraminiferal-based indices neglect the heavy metal increase encountered in the deepest stations. These findings suggest the need for a more in-depth analysis to improve the ecological status evaluation of marine benthic systems, including other descriptors as chemical pollutants in combination with biotic indices sensitive to organic matter enrichment