Search results for " marine sediments"

Dating of marine sediments by using unsupported 210Pb method

2009

In the framework of a more general study on marine species in sediments, it was necessary to obtain a time calibration of the different sections of the sampled sediment columns, both to estimate the pollution of the sediments and, particularly, to study the migration of foraminifers within the column. The method of the unsupported 210Pb, i.e. whose activity is not derived from the radioactive decay of its 226Ra parent, has been used. Since the activity of the supported 210Pb can be determined from the activity of 226Ra, the unsupported 210Pb activity can be calculated as the difference between 210Pb total and 226Ra activities. The unsupported 210Pb decays with its own half-life time, equal …

Microbial communities of polluted sub-surface marine sediments

2018

Abstract Microbial communities of coastal marine sediment play a key role in degradation of petroleum contaminants. Here the bacterial and archaeal communities of sub-surface sediments (5–10 cm) of the chronically polluted Priolo Bay (eastern coast of Sicily, Italy), contaminated mainly by n-alkanes and biodegraded/weathered oils, were characterized by cultural and molecular approaches. 16S-PCR-DGGE analysis at six stations, revealed that bacterial communities are highly divergent and display lower phylogenetic diversity than the surface sediment; sub-surface communities respond to oil supplementation in microcosms with a significant reduction in biodiversity and a shift in composition; the…

Possible impacts of Hg and PAH contamination on benthic foraminiferal assemblages: An example from the Sicilian coast, central Mediterranean

2007

The Palermo and Augusta urban/industrial areas (Sicily) are examples of contaminated coastal environments with a relatively high influx of unregulated industrial and domestic effluents. Three sediment box-cores were collected offshore of these urban/industrial areas in water depths of 60-150 m during two cruises (summers 2003/2004), dated by (210)Pb and (137)Cs, and analysed for total mercury concentration and total polycyclic aromatic hydrocarbon (PAH) concentration. Benthic foraminiferal assemblages were also examined (in terms of their distribution and morphology) to assess the potential use of benthic foraminifera as bioindicators of pollutant input and environmental change in these Med…

Preliminary insights about the treatment of contaminated marine sediments by means of bioslurry reactor: Process evaluation and microbiological chara…

2022

Abstract Contaminated marine sediments represent a critical threat towards human health and ecosystems, since they constitute a potential reservoir of toxic compounds release. In the present study, a bioslurry reactor was studied for the treatment of real marine sediments contaminated by petroleum hydrocarbons. The experimental campaign was divided in two periods: in the first period, microcosm trials were carried out to achieve useful indicators for biological hydrocarbon removal from sediments. The microcosm trials highlighted that the inoculum of halotolerant allochthonous bacteria provided the highest performance followed by autochthonous biomass. Based on the achieved results, in the s…

CLASSIFICATION AND TAXONOMY OF MODERN BENTHIC SHELF FORAMINIFERA OF THE CENTRAL MEDITERRANEAN SEA

2014

Distribution of rare earth elements in marine sediments from the Strait of Sicily (western Mediterranean Sea): Evidence of phosphogypsum waste contam…

2010

Concentrations of rare earth elements (REE), Y, Th and Sc were recently determined in marine sediments collected using a box corer along two onshore–offshore transects located in the Strait of Sicily (Mediterranean Sea). The REE + Y were enriched in offshore fine-grained sediments where clay minerals are abundant, whereas the REE + Y contents were lower in onshore coarse-grained sediments with high carbonate fractions. Considering this distribution trend, the onshore sediments in front of the southwestern Sicilian coast represent an anomaly with high REE + Y concentrations (mean value 163.4 lg g 1) associated to high Th concentrations (mean value 7.9 lg g 1). Plot of shale-normalized REE + …

Messa a punto di un protocollo sperimentale per la ricerca di Enterovirus in sedimenti marini

2009

In riferimento al Decreto Ministeriale del 24/01/1996, il controllo dei fondali marini utilizzati per il ripascimento dei litorali, costituisce un passo importante per la valutazione della salubrità dell’ambiente marino e dei prodotti ittici da allevamento, con particolare riferimento alla coltivazione di molluschi eduli lamellibranchi. Diversi studi, infatti, hanno dimostrato come i sedimenti, per le loro caratteristiche chimico-fisiche, rappresentano dei “serbatoi” di agenti microbici di varia natura che, da qui possono essere risospesi nelle acque, compromettendo la salubrità dell’ambiente. Poiché i molluschi eduli lamellibranchi sono organismi filtratori e trattengono agenti patogeni ca…

Modelling biogeochemical processes in sediments from the north-western Adriatic Sea: response to enhanced particulate organic carbon fluxes

2018

This work presents the result of a study carried out in the north-western Adriatic Sea, by combining two different types of biogeochemical models with field sampling efforts. A longline mussel farm was taken as a local source of perturbation to the natural particulate organic carbon (POC) downward flux. This flux was first quantified by means of a pelagic model of POC deposition coupled to sediment trap data, and its effects on sediment bioirrigation capacity and organic matter (OM) degradation pathways were investigated constraining an early diagenesis model by using original data collected in sediment porewater. The measurements were performed at stations located inside and outside the ar…

Seasonal changes in sediment core PS1795-2

2014

The Weddell Sea and the associated Filchner-Rønne Ice Shelf constitute key regions for global bottomwater production today. However, little is known about bottom-water production under different climate and icesheet conditions. Therefore, we studied core PS1795, which consists primarily of fine-grained siliciclastic varves that were deposited on contourite ridges in the southeastern Weddell Sea during the Last Glacial Maximum (LGM). We conducted high-resolution X-ray fluorescence (XRF) analysis and grain-size measurements with the RADIUS tool (Seelos and Sirocko, 2005, doi:10.1111/j.1365-3091.2005.00715.x) using thin sections to characterize the two seasonal components of the varves at sub-…