Settlement seasonality and temporal changes in hard substrate macrozoobenthic communities of Lesina Lagoon (Apulia, Southern Adriatic Sea)

The macrofauna settling on experimental substrates was studied at two sites of the Lesina Lagoon to test its possible role in monitoring ecological variations in a brackish-water ecosystem. The community settlement was seasonally investigated on 3-month-old wooden poles; the development was monitored from 2001 to 2005. Comparisons with benthic assemblages settled on 10-yr-old poles were also performed. The main hydrological parameters were periodically measured during the study. A total of 38 species were collected. The assemblage reached the highest development in the central lagoon, showing relevant carbonate structures which supported a rich vagile fauna. Close to the sea-water inlet species richness and abundance values were lower, with the disappearance of some brackish-water species. A remarkable salinity drop during 2004 produced some faunistic changes in the assemblages, which however maintained different structures between the study sites, thus confirming macrozoobenthos as an efficient bioindicator of different environmental conditions for transition biotopes and a useful investigation tool in monitoring programmes.     

Contamination levels and state assessment in the lakes of the Oliveri-Tindari Lagoon (North-Eastern Sicily,Italy)

The Oliveri-Tindari Lagoon, located in North-Eastern Sicily (Italy) and composed of six lakes, is subject to continuous environmental changes. An integrated study focusing on sediment features and levels of contamination was carried out for three of the six lakes, which are of ancient origin: Verde, Mergolo della Tonnara and Marinello. A high primary production (26.89 μg l^?1) was detected at Lake Verde; texture classification showed a typical grain size in the sediments of all lakes; the study of macronutrients highlighted 17.08 of total carbon in sediments from Lake Mergolo della Tonnara; toxic elements were detected at higher concentrations in the sediments of Lake Marinello in comparison to the others, while arsenic was found in high concentrations in all the samples tested, especially in Lake Verde, with a mean value of 17.25 mg kg^?1 dry weight (d.w.). All the organic contaminants, except 4, 4′-dichlorodiphenyldichloroethylene, were below the detection limits in the sediments. Minimal microbiological contamination was found in both water and sediment samples. In the latter, we isolated several bacterial strains thriving in the presence of arsenic, which play a role in the biogeochemical cycle of arsenic. These preliminary results, obtained for the first time using a multidisciplinary approach, provide general information about the Oliveri-Tindari Lagoon area.     

A Chemical Characterization of A Lagoon Ecosystem: The Sacca Di Goro (Po River Delta, Italy)

This work reports on the results of a preliminary estimate of the presence and distribution of common and rare elements in a typical estuarine environment of the Po River Delta. Different environmental compartments (sediment, water, macroalgae and benthic animals) were considered, and analysis conducted on samples taken at two different sites characterized by low and high hydrodynamic regime. Resulting evidence of differences between the matrices, especially in relation to their different nature and sampling site are given.     

Hazardous and essential trace elements profile in the different soft tissues of Lithophaga lithophaga (Linnaeus, 1758) from Southern Adriatic Sea (Italy)

A characterization study of 7 hazardous (Hg, Pb, Cd, As, Cr, U, and Ni) and 11 essential (Co, Mo, Se, Cu, Zn, V, Ca, Al, Sr, Mn, and Fe) trace elements in date mussels (Lithophaga lithophaga,Linnaeus, 1758) was carried out by inductively coupled plasma mass spectrometer. Date mussels (231 individuals), caught in the Gulf of Manfredonia (Southern Italy), were divided into 4 size-related groups. The different tissues (muscle, stomach, hepatopancreas and rest of soft tissues) were separated and analyzed to study the capability of absorption of this species. No particular differences were reported on the basis of the shell size; the soft tissues play an important role on the accumulation levels of hazardous and essential trace elements. These marine animals may be considered a good bioindicator of marine environmental pollution for their longevity and habitat permanence peculiarities.     

Accumulation of Organochlorine Compounds in Oysters (Crassostrea Gasar) of an Estuarine Environment: Case of A Tropical Lagoon in the Gulf of Guinea

As part of a pollution monitoring study, oysters (Crassostrea gasar) were sampled in June 1996, in order to determine the concentrations and distribution of chlorinated hydrocarbons in two stations (near Boulay Island and Riviera Golf) of the Ebrie Lagoon, in the Abidjan area.

The chromatographic analysis of the oven dried samples revealed the presence of PCBs (2.13 to 86.22 ppb or ng/g dry weight), DDE (<0.48 to 169.55 ppb), DDD (<1.04 to 60.27 ppb), DDT (1.43 to 77.81 ppb, lindane (<0.22 to 91.64 ppb), aldrin (<0.30 to 154.1 ppb), endrin (<0.23 to 293.31 ppb) and dieldrin (<0.26 to 199.74 ppb). the results indicated high concentrations in oysters sampled near Boulay Island, due to industrial, agricultural and port activities going on in this area.

Compared to DDD/ΣDDT and DDT/ΣDDT, the DDE/ΣDDT ratios were high indicating old DDT inputs. the ΣDDT/PCBs ratios were higher than 1 illustrated the predominance of organochlorine inputs from agriculture activities. the presence of lindane in both stations illustrated the problem of fishing with toxic products.

Negative correlations found between dry tissue weight and organochlorine compounds concentrations showed that young oysters may concentrate more of these substances. More studies are needed in order to make any conclusions on their bioaccumulation trends.     

As(V)-reduction to As(III) by arsenic-resistant Bacillus spp. bacterial strains isolated from low-contaminated sediments of the Oliveri-Tindari Lagoon,Italy

Five arsenic-resistant bacterial strains designated MT1, MT2, MT3, V1 and V2 were isolated from sediments of the Oliveri-Tindari Lagoon (Italy), which comprises six small lakes whose sediments contain low arsenic concentrations. Phylogenetic analysis of the 16S rRNA gene sequences assigned them to the genus Bacillus. Bacillus sp. strain MT3 showed higher tolerance to As(III) and As(V), as indicated by minimum inhibitory concentrations of 14 and 135 mmol^?1, respectively. Bacillus sp. strain V1 showed growth inhibition at 14 mmol^?1 in the presence of As(III) and at 68 mmol^?1 in the presence of As(V), whereas the arsenic resistance of Bacillus sp. strain MT1 was 10 and 27 mmol^?1 for As(III) and As(V), respectively. The strains Bacillus spp. MT2 and V2 showed low levels of As(III) and As(V) resistance, as it was unable to grow at concentrations>7 and 14 mmol^?1, respectively. The isolated arsenic-resistant Bacillus spp. strains were able to reduce As(V) to As(III), especially Bacillus spp. strain MT3. This study suggests that the isolated bacterial strains play a role in the arsenic biogeochemical cycle of arsenic-poor sediments in the Oliveri-Tindari Lagoon.     

Historical maps and satellite images as tools for shoreline variations and territorial changes assessment: the case study of Volturno Coastal Plain (Southern Italy)

Anthropic pressure has caused severe variations of Mediterranean coastal areas currently hosting about 480 million people. The replacement of natural land covers with crops and urban environment coupled with the reduction of sediment supply to the coast, subsidence, Relative Sea Level Rise and the high frequency of storm events, have caused severe shoreline erosion. In this paper, we stress the key role of historical maps, topographic maps and free satellite images to forecast the rates of coastline changes and to recognize the main features of past landscapes as tools for risk reduction. This data was recorded into a Geographical Information System dedicated to coastal management that allows to compare different coastal zones and elaborate maps. The analysis was applied to the case study of Volturno Coastal Plain (VCP), extending from the town of Mondragone to Patria Lake (Campania Region, Southern Italy). Indeed, the intense territorial modification that occurred between the seventies and eighties, coupled with the exposure to coastal erosion, make the VCP a good test area. The spatial analysis algorithms allowed to outline the main features of past landscapes and how they changed from roman times to present while the coastal evolution (erosion, accretion) and possible future coastal trend was assessed with the Digital Shoreline Analysis System (DSAS) software. Starting from the Bourbon domain, the reclamation caused the first great territorial change (e.g. wetlands were transformed into agricultural lands, regimentation of surperficial water) but the negative effects of antrophic pressure, as the intense urbanization of the coastal belt, emerged in the seventies of the last century. The shoreline position was defined for 9 time intervals (from 1817 to 2012) as the ratio of the distance between two shorelines and the relative elapsed time. Moreover, for the 1957–1998 and 1998–2012 time windows, the shoreline trends were calculated with the weighted linear regression method. The first trend pointed out an intensive erosional phase (mean value: 5 m/yr) for a wide sector close to the Volturno River mouth, the eroded sediment nourished the beaches of other coastal sectors. This phase was related to the reduction of River sediment supply mainly due to the construction of the Ponte Annibale dam on the Volturno River. The second (1998–2012) showed an alternation of erosion and accretion sectors due to a sediment starved condition to deltaic zone and to a sequence of 52 sea protection works in the Gaeta Gulf. Furthermore, the regression values of more recent time interval, was assumed as a scenario to draw the probable shoreline position in 2022. The overlay of this shoreline on the Technical Maps of Campania Region at 1:5000 scale highlighted the urban area that could be exposed to damages.     

Sediments distribution of trace metals in a coastal lagoon (Southern Sardinia,Mediterranean Sea): assessment of contamination and ecological risk

Coastal lagoons are subject to several sources of contaminations. To shade light on the contamination level of the Santa Gilla lagoon (Tyrrhenian Sea) we investigated the spatial distribution of Cr, Ni, Pb, Zn and Hg in sediments and their correlation with grain size and organic matter contents. Moreover, sediment contamination levels and the ecological risk associated with metal concentration were assessed using different abiotic indicators. The lagoon is characterised by low levels of contamination, with exceptions for Pb and Hg, whose distribution reflects the position of an old chlor-alkali plant and that of an airport. These results indicate that the restoration put in place 30 years ago have not reached the expected target and that the presence of the airport deserves further attention. In the outer section of the lagoon, where clam fishery occurs, we observed low levels of contamination suggesting that such artisanal fishery could somehow help mobilising metals. We conclude that the area exposed to Hg pollution, though tentatively restored, still suffers of a potential risk of ecosystem deterioration. We pinpoint that further investigations on the mobility, bioavailability and toxicity of metals are needed to finally address the actual impairment of the Santa Gilla lagoon.     

Seasonal variation and partition of trace metals (Fe, Zn, Cu, Mn, Cr, Cd and Pb) in surface sediments: relationship with physico-chemical variables of water from the Calabar River, South Eastern Nigeria

The seasonal variation and partition of trace metals (Fe, Cu, Zn, Mn, Cd, Cr and Pb) in the surface sediments of the Calabar River are reported. Chemical partition of the metals in the sediments reveals that 2–30% of the total metal load was contributed by the non-detrital (acid-soluble) fraction, while fine-grained host minerals/compounds are the main carriers of the detrital (acid-insoluble) fraction (70–98%). Using multivariate statistical analysis, the seasonal fluctuations in the distribution of some of the metals show significant influence by physio-chemical changes (dissolved oxygen, pH, salinity and conductivity) in the water column. Fe–Mn oxide grain coatings and sulphide materials have been identified as scavengers of some of the non-detrital and detrital trace metals in the sediments. On the basis of index of geoaccumulation (I-geo) and comparison with previous studies, the Calabar River surface sediments have been classified as unpolluted.