Simulating the fate of indigenous antibiotic resistant bacteria in a mild slope wastewater polluted stream

The fate of indigenous surface-water and wastewater antibiotic resistant bacteria in a mild slope stream simulated through a hydraulic channel was investigated in outdoor experiments.The effect of(i) natural(dark) decay,(ii) sunlight,(iii) cloudy cover,(iv) adsorption to the sediment,(v) hydraulic conditions,(vi) discharge of urban wastewater treatment plant(UWTP)effluent and(vii) bacterial species(presumptive Escherichia coli and enterococci) was evaluated.Half-life time(T1/2) of E. coli under sunlight was in the range 6.48–27.7 min(initial bacterial concentration of 10~5 CFU/mL) depending on hydraulic and sunlight conditions. E. coli inactivation was quite similar in sunny and cloudy day experiments in the early 2 hr, despite of the light intensity gradient was in the range of 15–59 W/m~2; but subsequently the inactivation rate decreased in the cloudy day experiment(T1/2= 23.0 min) compared to sunny day(T_(1/2)= 17.4 min). The adsorption of bacterial cells to the sediment(biofilm) increased in the first hour and then was quite stable for the remaining experimental time. Finally, when the discharge of an UWTP effluent in the stream was simulated, the proportion of indigenous antibiotic resistant E. coli and enterococci was found to increase as the exposure time increased, thus showing a higher resistance to solar inactivation compared to the respective total populations.     

Framework for high-resolution climate change impact assessment on grapevines at a regional scale

Understanding the impacts of climate change on viticulture is especially essential in those areas producing high-quality wines. In this work, we create an operational framework to investigate climate change impact on viticulture in the Tuscany region (central Italy) the viticulture industry of which relies on producing high-quality wines to compete in a global market. The framework includes (i) statistical downscaling of General Circulation Model (GCM) outputs for the period 1975–2099 to a local scale; (ii) the use of downscaling outputs as driving variables in specific simulation models; (iii) the spatial interpolation of model outputs to feed an economic and (iv) a quality model. The results show that as a consequence of a progressive increase in temperature and a decrease in rainfall, (a) the area potentially suitable for grapevine cultivation increases; (b) the grapevine growth cycle becomes shorter; (c) the final yield is gradually reduced, particularly in those areas characterised by quality cultivation regulation; and d) the premium wine quality production areas shift towards higher elevations. The proposed framework revealed itself to be an effective tool for climate change impact assessment at a very local scale. Additionally, this approach may be easily extended to testing the effect of different adaptation strategies in terms of management practices (e.g. irrigation) and grape varieties (e.g. longer or shorter cycle, advanced or delayed bud burst).     

Phylogeography of the diamond turbot (Hypsopsetta guttulata) across the Baja California Peninsula

We compared morphology and sequenced nuclear and mitochondrial genes from 11 populations of a previously genetically unstudied “Baja California disjunct” species, the diamond turbot (Hypsopsetta guttulata). This species exhibits very limited adult movement and restriction to soft-bottom habitats but has a moderately long pelagic larval duration. Therefore, if pelagic larval duration is correlated with gene flow between Gulf of California and Pacific populations, we expect a reduced level of genetic and morphological differentiation. However, if adult habitat and ecology have more effect on gene flow, we expect the populations in the two bodies of water to be more highly differentiated. We used logistic regression to compare morphological features and phylogenetic and population genetic analyses to compare nucleotide sequence data. Gulf of California H. guttulata are different from Pacific populations in morphology and both mitochondrial and nuclear gene sequences. MtDNA shows reciprocal monophyly, and nuclear sequences from the Gulf of California formed a monophyletic group. Population genetic analyses also suggest further population subdivision within the Pacific and within the Gulf of California. We argue that adult ecology has a significant effect on migration rates among populations in the Pacific Ocean and the Gulf of California.     

Epistemic uncertainty in fault tree analysis approached by the evidence theory

Process plants may be subjected to dangerous events. Different methodologies are nowadays employed to identify failure events, that can lead to severe accidents, and to assess the relative probability of occurrence. As for rare events reliability data are generally poor, leading to a partial or incomplete knowledge of the process, the classical probabilistic approach can not be successfully used. Such an uncertainty, called epistemic uncertainty, can be treated by means of different methodologies, alternative to the probabilistic one. In this work, the Evidence Theory or Dempster–Shafer theory (DST) is proposed to deal with this kind of uncertainty. In particular, the classical Fault Tree Analysis (FTA) is considered when input data are supplied by experts in an interval form. The practical problem of information acquisition from experts is discussed and two realistic scenarios are proposed. A methodology to propagate such an uncertainty through the fault tree up to the Top Event (TE) and to determine the belief measures is supplied. The analysis is illustrated by means of two simple series/parallel systems. An application to a real industrial safety system is finally performed and discussed.     

Inertization of hazardous dredging spoils

Vitrification and production of ceramics materials starting from sediment excavated from Venice lagoon is described. This sediment is classified as toxic waste because contains several heavy metal ions and organic pollutants and was successfully vitrified at 1200-1350 degrees C. Twenty weight percentage of glass cullet, coming from a community glass recycling program, was added to the raw materials, previously calcined at 900 degrees C, as a way of adjusting the variations of composition of the individual sediment batches. Chemical durability (leaching) tests showed that the optimized glass compositions are inert, and thus not only volume reduction but also inertization of the waste was obtained by this process. Moreover, the economics of the entire process was analysed. The valorization of the waste was accomplished by the subsequent processing of the glass derived from the inertization. Glass ceramic materials were produced by viscous phase sintering of pressed glass powders which crystallized during the densification process. Sintered glass ceramic products had good mechanical characteristics (HV = 7.5 GPa, bending strength 150 +/- 8 MPa), making them suitable for applications in the building industry.     

Tropical fishes in a temperate sea: evolution of the wrasse <Emphasis Type="Italic">Thalassoma pavo</Emphasis> and the parrotfish <Emphasis Type="Italic">Sparisoma cretense</Emphasis> in the Mediterranean and the adjacent Macaronesian and Cape Verde Archipelagos

The northeastern Atlantic and the Mediterranean Sea share geological histories and display great faunal affinities. The majority of the Mediterranean species have Atlantic origins, with a few species with tropical affinities. These include the parrotfish Sparisoma cretense and the wrasse Thalassoma pavo that are restricted to the subtropical northeastern Atlantic, the Macaronesian archipelagos (Azores, Madeira, and Canaries) and the southern Mediterranean. The Pleistocene glaciations have been described as having different effects on the fauna of the two regions. During glacial peaks, Mediterranean waters remained warmer than those of the adjacent Atlantic. Within the eastern Atlantic, the effects of Pleistocene glaciations were differentiated. Here, we perform a comparative analysis focusing on T. pavo and S. cretense populations from the northeastern Atlantic and the Mediterranean to assess the effects of Pleistocene glaciations in these two species. Sequences from the mitochondrial control region were obtained and analyzed combining phylogeographic and demographic approaches. Gene flow between Atlantic and Mediterranean populations was shown to be very high. The Mediterranean populations of T. pavo and S. cretense showed high levels of genetic diversity, even in the eastern basin, pointing to an ancient colonization event. This suggests that both species must have been able to persist in the Mediterranean during the cold Pleistocene periods. Historical migration estimates revealed a Mediterranean towards Atlantic trend in the case of T. pavo, which may reflect the re-colonization of areas in the Atlantic by fish that survived the cold phases in relatively warmer Mediterranean refugia. Our data also showed that within the Macaronesian Archipelagos, migrations occurred from Madeira towards the Azores, for both T. pavo and S. cretense, thus supporting a post-glacial colonization of the Azores by fish that persisted in the warmer region of Madeira. Similar geographic distributions, thermal affinities, and means of dispersion for T. pavo and S. cretense resulted in a similar response to the effects of Pleistocene glaciations, as evidenced by identical phylogeographic patterns.     

Phylogeography, historical demography, and the role of post-settlement ecology in two Hawaiian damselfish species

Coral reef fish generally have relatively sedentary juvenile and adult phases and a presumed highly dispersive pelagic larval phase, yet previous studies that have tried to relate pelagic larval duration (PLD) to population structure have given inconsistent results. In the present study, the population structures of two damselfishes, Stegastes fasciolatus and Dascyllus albisella, were examined using mitochondrial control region sequences. The two species have similar PLDs (∼25 and 27 days respectively), but consistently differ in their settlement preferences, habitat, and densities in populations throughout the Hawaiian Archipelago, from Hawaii north to Kure Atoll, and south to Johnston Atoll. Information on habitat preferences and population densities were collected between September 2000 and October 2002, and tissue samples for the genetic studies were collected between January and April 2004. Based on the differences in habitat and abundance of the two species, the expectation was that S. fasciolatus would have high genetic variability but little population structure compared to D. albisella, and this was largely confirmed. Stegastes fasciolatus had little population structure in most of the Hawaiian Islands, and D. albisella showed evidence of strong population structure throughout its range. An exception to this pattern was the large difference between the Kure Atoll population of S. fasciolatus and all others. These results suggest that the interaction of several biological factors (e.g. species-specific spawning habitat and season) with environmental factors (e.g. seasonal wind and current patterns) may have more influence on population structure than single life history characteristics, such as the PLD.     

Effects of middle-term land reclamation on nickel soil-water interaction: a case study from reclaimed salt marshes of Po River Delta,Italy

Reclaimed salt marshes are fragile environments where water salinization and accumulation of heavy metals can easily occur. This type of environment constitutes a large part of the Po River Delta (Italy), where intensive agricultural activities take place. Given the higher Ni background of Po River Delta soils and its water-soluble nature, the main aim of this contribution is to understand if reclamation can influence the Ni behavior over time. In this study, we investigated the geochemical features of 40 soils sampled in two different localities from the Po River Delta with different reclamation ages. Samples of salt marsh soils reclaimed in 1964 were taken from Valle del Mezzano while soils reclaimed in 1872 were taken nearby Codigoro town. Batch solubility tests and consecutive determination of Ni in pore-water were compared to bulk physicochemical compositions of soils. Bulk Ni content of the studied soils is naturally high, since these soils originated from Po River sediments derived from the erosion of ultramafic rocks. Moreover, it seems that Ni concentration increases during soil evolution, being probably related to the degradation of serpentine. Instead, the water-soluble Ni measured in the leaching tests is greater in soils recently reclaimed compared to the oldest soils. Soil properties of two soil profiles from a reclaimed wetland area were examined to determine soil evolution over one century. Following reclamation, pedogenic processes of the superficial horizons resulted in organic matter mineralization, pH buffer, and a decrease of Ni water solubility from recently to evolved reclaimed soil.     

Gene flow at three spatial scales in a coral reef fish, the three-spot dascyllus, Dascyllus trimaculatus

Dispersal in coral reef fishes occurs predominantly during the larval planktonic stage of their life cycle. With relatively brief larval stages, damselfishes (Pomacentridae) are likely to exhibit limited dispersal. This study evaluates gene flow at three spatial scales in one species of coral reef damselfish, Dascyllus trimaculatus. Samples were collected at seven locations at Moorea, Society Islands, French Polynesia. Phylogenetic relationships and gene flow based on mitochondrial control region DNA sequences between these locations were evaluated (first spatial scale). Although spatial structure was not found, molecular markers showed clear temporal structure, which may be because pulses of settling larvae have distinct genetic composition. Moorea samples were then compared with individuals from a distant island (750 km), Rangiroa, Tuamotu Archipelago, French Polynesia (second spatial scale). Post-recruitment events (selection) and gene flow were probably responsible for the lack of structure observed between populations from Moorea and Rangiroa. Finally, samples from six Indo-West Pacific locations, Zanzibar, Indonesia, Japan, Christmas Island, Hawaii, and French Polynesia were compared (third spatial scale). Strong population structure was observed between Indo-West Pacific populations. Received: 26 May 2000 / Accepted: 10 October 2000     

Heat stress and crop yields in the Mediterranean basin: impact on expected insurance payouts

Insurance programmes have been indicated as a tool to reduce the economic risk associated with climate change, and crop growth simulation models can be used effectively to assess future trends in crop insurance payouts. This paper assesses the economic role of increasing weather extremes under future climate change on the expected insurance payouts for durum wheat (Triticum turgidum L. spp. durum) over the Mediterranean basin, focusing attention on the effects of heat stresses (HSs). A crop growth simulation, Sirius Quality version 2 (SQ2), calibrated for three varieties (long, medium and short growth cycle) was applied on seven sites under present (1975–1990) and future climate conditions (2030–2050) obtained from five regional circulation models under SRES scenario A1b. The intensity of HSs at anthesis was included as reducing factor of yield originally simulated by SQ2 calculated according to a specific empirical model. Simulated yields were then fitted to the most appropriate distribution, which was used to calculate the expected payouts according to the probability of yields being below a guaranteed level. We found that the simulated crop yields were, in general, negatively skewed and that Weibull probability density function (PDF), admitting negative skewing, provided the best performances in their fitting. The simulation of HSs modified the original shape of the Weibull PDF by increasing the skewness of the distribution. The results of the insurance model indicated that the modification of crop PDFs induced by HSs led to a general increase in payouts with respect to unstressed conditions, with a marked difference between present (+11 %, on average for the selected sites) and future periods (+25 %). When compared to the present, a general decrease in payouts (?1.1 %) was observed when HSs were not included in the simulations. Conversely, HSs impact resulted in a general increase in payouts (+10.3 %) where the highest increase was detected for the long growth cycle variety (+16.6 %) and the lowest for that with short growth cycle (?1.6 %). These results emphasize the importance of the appropriate characterization of crop yield distribution, the economic implications of HSs in a risk management context and a possible strategy to cope with climate change and variability.