Do mining activities significantly affect feeding behavior of freshwater benthic macroinvertebrates? A case study in South Sardinia (Italy)

We investigated the cascading effects of chemical contaminants on alder leaf detritus quality and the exploitation of this feeding resource by benthic macroinvertebrates (isopods, gastropods, and mayfly nymphs). Trophic behavior and energetics of benthic macroinvertebrates were used to evaluate the effects of contaminants on detritus exploitation. A two-way factorial nested experimental design was used to statistically quantify how leaf detritus origin (polluted and unpolluted streams) and the pollution level of the site selected for microbial conditioning of the detritus could affect the feeding resource quality for aquatic benthic macroinvertebrates, as measured by their trophic behavior (i.e. food selection) and exploitation (i.e. food ingestion). Alder leaves collected from a polluted stream in a former mining area (South-Sardinia, Italy) had Cd, Pb, and Zn concentrations up to 10 times that of leaves collected from an unpolluted stream. When benthic macroinvertebrates were given the option to choose, they all selected leaves from the unpolluted stream and/or those conditioned in the unpolluted stream. Ingestion rates were also significantly affected by both considered factors: leaf origin and conditioning. In addition, synergistic effects strongly increased the chemical contaminant stress on the leaf detritus quality. These results show that the terrestrial component of land–water ecotones affected by mining can be a relevant indirect pathway of chemical stress to benthic macroinvertebrate species

Production of methylmercury by sulphate-reducing bacteria in sediments from the orbetello lagoon in presence of high macroalgal loads

Methylmercury is a potent neurotoxin affecting shallow-water ecosystems. Mercury polluted sediment samples were collected at six different sites in the Orbetello Lagoon (central Italy) characterized by high levels of silt, iron, manganese hydroxides, and organic matter originated the latter originated from the decomposition of macroalgae. Porous water pointed out the presence of sulphates, methylmercury, and sulphides. Slurries arranged in anaerobic conditions from sediment aliquots from the six sites, with the addition of ionic mercury, highlighted the production of methylmercury. Sulphate reducing bacteria (SRB) were quantified in lagoon sediments; furthermore, sediments cultured under anaerobic conditions showed SRBs active in mercury methylation. Anaerobic cultures of SRB, amended with ionic mercury, produced methylmercury during the growth of bacterial cells. The percentage of aerobic mercury resistant bacteria was pointed out at each sampling site, evidencing the presence of bioavailable mercury. Several aerobic mercury resistant bacteria were isolated and their level of resistance to inorganic and organic forms of mercury was evaluated. These isolates may be potentially used for eventual bioremediation processes. Mercury methylation by SRB in the Orbetello Lagoon sediments was described for the first time, focusing the attention on the need for possible bioremediation processes by using autochthonous mercury resistant bacteria. Moreover, the influence of algal biomass on mercury methylation was highlighted for the first time in this lagoon ecosystem. The importance of removing algal biomass, as it represents a source of organic matter favouring the process of mercury methylation, was strongly pointed out in this study

Recent changes in macroalgae distribution patterns in the Orbetello lagoon (Italy)

This study related recent distribution changes in seven macroalgae taxa (Acetabularia acetabulum, Chaetomorpha linum, Cladophora sp., Gracilariopsis longissima, Spyridia sp., Ulva laetevirens, Valonia aegagrophyla) to spatial (basin) and temporal (time) trophic differences in a meso-eutrophic Mediterranean coastal lagoon (Orbetello, Italy). In July 2003 and July 2009, the coverage percentage (CP) of each considered taxon was measured in 38 stations equally distributed in the Western and Eastern lagoon basins. All data were analysed using SURFER v8.0 software along with ANOVA, ANOSIM and multivariate analyses to produce geostatistical spatial distribution maps and to estimate statistical probabilities for "basin" and "time" factors. Data from this study were integrated with data on phanerogams reported by Giovani et al. (2010)to evaluate changes occurring at a functional group level from 2003-2009 using the Ecological Evaluation Index (EEI). Observed macroalgae changes may have been due to lagoon management activities performed during the study period. The removal of direct nitrate inputs seems to have forced specie-specific shifts that were highly significant only in the Western basin. Statistically significant differences at the taxon level have been indicated for Spyridia sp. (basin and time) and Cladophora sp. (time) taxa. Other non-significant changes included a rarefaction of Chaetomorpha linumin the Western basin and Spyridia sp. in the Eastern basin, and an increase of Gracilariopsis longissima, C. linum and Valonia aegagrophyla in the Eastern basin. EEI application indicated a general improvement in water quality due to management measures applied in Western basin, whereas the Eastern basin evidences stability/slight degradation from 2003-2009

Intra-Laboratory Calibration Exercise for Quantification of Microplastic Particles in Fine-Grained Sediment Samples: Special Focus on the Influence of User Experience

An intra-laboratory calibration to quantify microplastic in fine-grained marine sediments was performed with two objectives: (a) to determine the recovery rate of self-produced microplastics characterized by a size ranging from 220 µm to 5 mm and differing in color (pink, orange, gray, yellow, silver), shape (fragments, filaments, spheres, films), and chemical composition (polystyrene, polyethylene, polyvinyl chloride, acrylonitrile-butadiene-styrene, polypropylene, poly(methyl methacrylate)) artificially introduced into real samples; and (b) to analyze whether operator experience can be a key factor in the quality of the results. To answer this question, the same protocol was assigned to an experienced and an inexperienced operator. The results of this comparison are detailed in terms of root mean square and percent error. Possible strategies to increase the recovery rate are presented, and an ad hoc category, namely “glitter”, was created to adjust the results with respect to this unique type of microplastic usually ignored and excluded from the analysi

levels of polybrominated diphenyl ethers in commercial food in siena province tuscany italy

This study reports on the presence and levels of polybrominated diphenyl ethers (PBDEs) in food items collected during the period 2004-2010 in commercial food shops in Siena (Southern Tuscany, Central Italy), in order to evaluate risk to humans due to food consumption. We have considered the following eight PBDE congeners to be of primary interest: BDE28, BDE47, BDE99, BDE100, BDE153, BDE154, BDE183 and BDE209. The overall results clearly show a strong difference in concentration of PBDEs between seafood and food from the terrestrial trophic web. PBDE concentrations in commercial food from terrestrial origin vary from an average of 156 pg g -1 fat in chicken breast (6 pg g -1 fresh weight) to an average of 404 pg g -1 fat in butter (125 pg g -1 f.w.). In seafood, average values are comprised between 174 pg g -1 f.w. in hake to 692 pg g -1 f.w. in swordfish. In several samples of swordfish PBDE values are higher than 1 ng g -1 f.w. If we consider PBDE congeners individually, BDE47 is the predominant one in seafood, with percentages above 50% in all species. In commercial food of terrestrial origin, BDE47 is predominant in beef, pork, bacon, butter and sausage (27%-35%), followed by BDE209 (25%-28%). In chicken breast, eggs and cow's milk, BDE209 is predominant (28%-32%) followed by BDE47 (25%-30%). The level of PBDEs found in bluefin tuna and swordfish, considering their importance in the human diet, suggests the need for particular care in our food choices

Pressures and impacts on structure, functioning and services in marine, terrestrial, and transitional ecosystems

Goal of the special issue - Given this premise, the special issue will gather theoretical, methodological, and applied papers focusing on the assessment of pressures and impacts on structure, functioning and services in marine, terrestrial, and transitional ecosystem

Spatial and temporal variations of nutrients and chlorophyll a in a Mediterranean coastal lagoon: Varano lagoon, Italy

The purpose of this paper is to assess the present status of a Mediterranean lagoon (Varano lagoon, Italy), basing on nutrient and chlorophyll a data. A water sampling in Varano lagoon was performed at 7 fixed stations from February 2004 to July 2005, collecting surface water samples to analyse ammonia, nitrite, nitrate, soluble reactive phosphorus (SRP) and soluble reactive silica (SRSi), chlorophyll a (chl a) and total suspended solids (TSS). Spatial and temporal distributions of chemical and biological parameters in Varano lagoon were examined to accomplish the goal of this study. Statistical tests were used to investigate the correlations between analysed variables and to characterize, from a spatial and temporal point of view, the lagoon in relation to each variable. Ammonia and nitrate did not showed good correlation (P<0.05). SRP was not correlated with any nutrient (only with Chl a, P<0.05). The seasonal distribution show a random pattern for soluble reactive phosphorus with relatively low mean concentrations (0.16 ± 0.03 µM) and a well-defined seasonal pattern for nitrate, with the highest mean value (34.44 ± 10.18 µM) recorded in the wet season (February 2004) and a high spatial variability. The most homogeneous chl a values were observed in both autumn and winter seasons with averages of about 1-1.5 µg . L-1; in contrast, higher mean values (5.50 µg . L-1 ) were recorded in July 2005. The ratio between the dissolved inorganic nitrogen species and SRP (N/P) in Varano lagoon was constantly high and it varied seasonally from about 300:1 during rainy seasons to 60-90:1 during dry seasons. High values of the N/P ratio in autumn and winter were accompanied by an increase in total N implying an input of nitrogen to the system probably associated with rainfall. The high fluctuation in the various chemical parameters in the lagoon during the rainy season suggested that this is the period of large variability, in which environmental processes as marine waters, freshwaters and wastewaters represent inputs that determine the spatial behaviour of the system

Looking for Nano- and Microplastics in Meiofauna Using Advanced Methodologies

: Meiofauna (body size within 30–1000 µm) are the community of microscopic invertebrates that live at the bottom of marine and freshwater ecosystems and play a key role in the food webs of these environments. Several studies have addressed the adverse effects of anthropic stressors on meiofauna; however, data on the presence and impact of plastic debris in wild meiofaunal organisms are scant. Since the amount of microplastic waste in sediments may surge rapidly, ascertaining the ingestion of these xenobiotics by the abundant micrometazoan community is necessary to understand their potential accumulation in aquatic food webs and their hazard to the health of the ecosystem. The absence of documentation in this regard may be due to the difficulty in detecting the small size of the plastic fragments meiofauna may potentially ingest. To overcome this difficulty, we developed an integrated approach based on different microscopic/spectroscopic techniques suitable for detecting plastic particles of sizes down to 200 nm.Meiofauna (body size within 30–1000 m) are the community of microscopic invertebrates that live at the bottom of marine and freshwater ecosystems and play a key role in the food webs of these environments. Several studies have addressed the adverse effects of anthropic stressors on meiofauna; however, data on the presence and impact of plastic debris in wild meiofaunal organisms are scant. Since the amount of microplastic waste in sediments may surge rapidly, ascertaining the ingestion of these xenobiotics by the abundant micrometazoan community is necessary to understand their potential accumulation in aquatic food webs and their hazard to the health of the ecosystem. The absence of documentation in this regard may be due to the difficulty in detecting the small size of the plastic fragments meiofauna may potentially ingest. To overcome this difficulty, we developed an integrated approach based on different microscopic/spectroscopic techniques suitable for detecting plastic particles of sizes down to 200 nm

Occurrence of POPs in sediments and tissues of European eels (Anguilla anguilla L.) from two Italian lagoons: Varano and Orbetello

Total levels of persistent organic pollutants (polychlorinated biphenyls, organochlorine pesticides,and polycyclic aromatic hydrocarbons) in sediments and edible tissues (muscle and liver) from a fish species of great local commercial interest (Anguilla anguilla L., yellow phase) were determined in Varano and Orbetello lagoons, Italy. The aim of this study was to improve knowledge on relationships occurring among levels of chemicals in sediments and fish tissues relating them reciprocally and to different intensities of human pressure. Studied ecosystems were selected due to the notable scientific knowledge acquired by previous detailed research on meteorology, geomorphology, hydrodynamics, types and distribution of local factors linked to different sources of human-made pollution. Samplings were performed in July 2009 according to a logic model based on a priori defined factors of interest and obtained results were statistically analysed in order to evaluate the significance of observed data segregation related to the selected factors. Concerning levels measured in sediments, significant differences were observed between lagoons in terms of ƩPAHs and ƩOCPs. According to National and international recognised sediment quality guidelines, results evidenced the occurrence of non-critical POPs values in sediments. Results on sediments are associated to very high levels in eel\u27s tissues. Concerning eels, Orbetello lagoon is characterized by significant higher values of ƩOCPs than Varano, evidencing the presence of an important OCPs local source. Different human pressure levels produce significant differences in both sediments and eel\u27s tissues in Varano and Orbetello lagoons