Gone fishing: Adélie penguin site-specific foraging tactics and breeding performance

AbstractThe ecological drivers underlying breeding performance are expected to differ across the geographical range of seabird species, but few studies have compared trade-offs between colonies with different local conditions. During chick-rearing (2000–01), we compared the foraging trips, diet and breeding parameters of two Adélie penguin colonies in the Ross Sea, at Edmonson Point (EdPo; ~2000 breeding pairs) and Inexpressible Island (InIs; ~24 000 breeding pairs). Penguins from InIs travelled farther and performed longer feeding trips. The quantity of food brought to the nest was the same for the two colonies, but penguins from InIs brought more fish and less krill. Eggs hatched earlier at EdPo. Breeding success did not differ, but chick weight during hatching–fledging was greater at InIs. Despite worse weather conditions at InIs, the larger proportion of high-energy food brought by penguins from InIs (i.e. fish) may explain their offspring's better performance. In addition, the persistence of fast ice at EdPo may have led to greater energy expenditure of breeding individuals, possibly reducing chick growth. The greater intraspecific competition expected at InIs may have been reduced by longer foraging trips and/or counteracted by the more nutritious diet. Our findings reveal complex trade-offs between foraging effort and environmental constraints in determining the breeding performance of Adélie penguins

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

Using PUF disk passive samplers to simultaneously measure air concentrations of persistent organic pollutants (POPs) across the Tuscany Region, Italy

AbstractPassive air samplers consisting of polyurethane foam (PUF) disks were deployed simultaneously over 2–4 month periods from April to July 2008 at 19 locations throughout the Tuscany Region at urban (n=9), rural (n=7) and agricultural sites (n=3). The purpose of the study was to assess the gas–phase air concentrations of PCBs, OCPs, PBDEs and PAHs on a local and regional scale. Derived air concentrations (pg m−3) ranged from below detection limit (BDL) to 300 for Σ6PCBs and from BDL to 30 for Σ3PBDEs. As expected, the highest PCB concentrations (pg m−3) were observed at urban sites, peaking in Piombino (300). PBDEs, however, exhibited a “reverse gradient” (i.e. rural>agricultural>urban) with highest air concentration at the rural site, Arcidoso (30). Levels of OCPs showed less distinct differences among the three site types. The most frequently detected OCPs were Endosulfan I, γ–HCH and α–HCH. Endosulfan I ranged from BDL to 2 200pg m−3, α–HCH from BDL to 610, and γ–HCH from BDL to 1 100. The high air concentrations of HCHs were surprising and possibly due to continued and illegal use – especially at agricultural and urban sites that exhibited the highest levels in air. PAHs showed highest concentrations (pg m−3) at agricultural and urban sites, ranging from 290 to 4 700 and were generally consistent with other data sets from Europe. PAHs were dominated by the 3–ring PAHs (76±6)%, with phenanthrene alone accounting for (45±11%) of the total PAHs. This study demonstrates the feasibility of using PUF disks as time–integrating passive air samplers for assessing local and regional scale concentrations of a wide range of POPs in central Italy. Given their low cost and simplicity, passive air samplers are the preferred option for conducting concurrent sampling at multiple sites for monitoring and research purposes

Using PUF disk passive samplers to simultaneously measure air concentrations of persistent organic pollutants (POPs) across the Tuscany Region, Italy

Abstract Passive air samplers consisting of polyurethane foam (PUF) disks were deployed simultaneously over 2–4 month periods from April to July 2008 at 19 locations throughout the Tuscany Region at urban (n = 9), rural (n = 7) and agricultural sites (n = 3). The purpose of the study was to assess the gas–phase air concentrations of PCBs, OCPs, PBDEs and PAHs on a local and regional scale. Derived air concentrations (pg m −3 ) ranged from below detection limit (BDL) to 300 for Σ 6 PCBs and from BDL to 30 for Σ 3 PBDEs. As expected, the highest PCB concentrations (pg m −3 ) were observed at urban sites, peaking in Piombino (300). PBDEs, however, exhibited a "reverse gradient" (i.e. rural>agricultural>urban) with highest air concentration at the rural site, Arcidoso (30). Levels of OCPs showed less distinct differences among the three site types. The most frequently detected OCPs were Endosulfan I, γ–HCH and α–HCH. Endosulfan I ranged from BDL to 2 200 pg m −3 , α–HCH from BDL to 610, and γ–HCH from BDL to 1 100. The high air concentrations of HCHs were surprising and possibly due to continued and illegal use – especially at agricultural and urban sites that exhibited the highest levels in air. PAHs showed highest concentrations (pg m −3 ) at agricultural and urban sites, ranging from 290 to 4 700 and were generally consistent with other data sets from Europe. PAHs were dominated by the 3–ring PAHs (76 ± 6)%, with phenanthrene alone accounting for (45 ± 11%) of the total PAHs. This study demonstrates the feasibility of using PUF disks as time–integrating passive air samplers for assessing local and regional scale concentrations of a wide range of POPs in central Italy. Given their low cost and simplicity, passive air samplers are the preferred option for conducting concurrent sampling at multiple sites for monitoring and research purposes

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

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

Agent-based simulation of a financial market

This paper introduces an agent-based artificial financial market in which heterogeneous agents trade one single asset through a realistic trading mechanism for price formation. Agents are initially endowed with a finite amount of cash and a given finite portfolio of assets. There is no money-creation process; the total available cash is conserved in time. In each period, agents make random buy and sell decisions that are constrained by available resources, subject to clustering, and dependent on the volatility of previous periods. The model herein proposed is able to reproduce the leptokurtic shape of the probability density of log price returns and the clustering of volatility. Implemented using extreme programming and object-oriented technology, the simulator is a flexible computational experimental facility that can find applications in both academic and industrial research projects.Comment: 11 pages, 3 EPS figures, LaTEX. To be published in Physica A (Proceedings of the NATO Advanced Research Workshop on Application of Physics in Economic Modelling, Prague 8-10 February 2001