Linking Terrestrial and Aquatic Ecosystems: Complexity, Persistence and Biodiversity in European Food Webs

In this work we have defined and analyzed the network structure, properties and composition of cohesive sub webs in two food web networks at two selected European sites: Ferto lake in Hungary and Ria Formosa lagoon in Portugal, respectively. The main objective of this work was to test and to apply a coherent methodology for the definition and analysis of trophic networks in typical European ecosystems. Persistence and cohesion of the two networks have been determined and studied. Moreover the biodiversity in terms of number of species have been measured. Several preliminary conclusions can be drawn on a basis of results obtained from application of network analysis indices and dynamical simulation. In terms of ecosystem stability the lake Ferto network (persistence 0.42) seems more stable than Ria Formosa (persistence 0.26), but if we consider the stability of the main k-core, we obtain opposite results (0.48 and 0.50 respectively). Taking into account the distribution of species in the k-core partition, the general structure of Ria Formosa network appears more complex than Ferto lake. In both networks a main core containing species taxonomically different is present, but in the Ria Formosa network (37.7%) the proportion of species inside the core is lower than in Ferto lake (60%), this can be an indication that the dimension of the main core is not related to size of the network in real ecosystems. This hypothesis is confirmed by results obtained from k-core partition of simulated networks. In both studied networks the cohesion (measured in terms of mean density and degree) of k-cores is greater than k-cores extracted from simulated networks generated by different models, this may indicate a complex and not arbitrary structure of ecological networks, not easily reproducible by models. In general the approach used appears to be able of defining the main proprieties of the trophic networks examined. The extension to other European ecosystems is needed for having a clearer and complete picture and to use data collected to simulation of different scenarios, afterwards the effects on network structure and ecosystem biodiversity as a function of different European environmental policies could be assessedJRC.H.5-Rural, water and ecosystem resource

Performance of Chlorella Vulgaris Exposed to Heavy Metal Mixtures: Linking Measured Endpoints and Mechanisms

Microalgae growth inhibition assays are candidates for referent ecotoxicology as a fundamental part of the strategy to reduce the use of fish and other animal models in aquatic toxicology. In the present work, the performance of Chlorella vulgaris exposed to heavy metals following standardized growth and photosynthesis inhibition assays was assessed in two different scenarios: (1) dilutions of single heavy metals and (2) an artificial mixture of heavy metals at similar levels as those found in natural rivers. Chemical speciation of heavy metals was estimated with Visual MINTEQ software; free heavy metal ion concentrations were used as input data, together with microalgae growth and photosynthesis inhibition, to compare different effects and explain possible toxicity mechanisms. The final goal was to assess the suitability of the ecotoxicological test based on the growth and photosynthesis inhibition of microalgae cultures, supported by mathematic models for regulatory and decision-making purposes. The C. vulgaris algae growth inhibition test was more sensitive for As, Zn, and Pb exposure whereas the photosynthesis inhibition test was more sensitive for Cu and Ni exposure. The effects on growth and photosynthesis were not related. C. vulgaris evidenced the formation of mucilaginous aggregations at lower copper concentrations. We found that the toxicity of a given heavy metal is not only determined by its chemical speciation; other chemical compounds (as nutrient loads) and biological interactions play an important role in the final toxicity. Predictive mixture effect models tend to overestimate the effects of metal mixtures in C. vulgaris for both growth and photosynthesis inhibition tests. Growth and photosynthesis inhibition tests give complementary information, and both are a fast, cheap, and sensitive alternative to animal testing. More research is needed to solve the challenge of complex pollutant mixtures as they are present in natural environments, where microalgae-based assays can be suitable monitoring tools for pollution management and regulatory purposes. Keywords: PAM; heavy metal mixtures; metals speciation; microalgae; toxicity

Thresholds of Contaminants: A Synthesis

A fundamental problem in ecotoxicology is the prediction of long term population and ecosystem-level effects of contaminant exposure based on dose response data of few individuals obtained over a short time period. In addition, environmental fluctuations will always affect significantly the population/ecosystem resilience. However, these fluctuations are not taken into account under dose-response experiments on individuals. In the Thresholds project we have analyzed some of these questions by using experiments, data analysis tools and modelling approaches. Several important finding may be summarized as follows: 1 Molecular level effects are detected even at concentrations that did not affect the macroscopic end point studied, i.e. growth rate. 2 Natural populations are more sensitive that populations in cultures. 3 There are differences for the same species at different environments, e.g. Mediterranean, Black Seas and Atlantic Ocean. 4 The environmental conditions and the time of release of the contaminant cause a variability of the response at ecosystem level that can reach 50%. 5 At the actual level of knowledge it is difficult to assess if the legal approach, based on the precautionary principle, is over or under conservative, when considering molecular and its long term effects, the combined effects of mixtures and the environmental fluctuations that affect all ecosystems. 6 A similar colour code to the one adopted for biological quality elements should be adopted for the definition of EQS, with values higher than the EQS as orange (poor). This will allow assessing contamination trends and an early detection of a chemical contamination problems. 7 In aquatic environments ecosystem experience the combined effects of mixtures. Ecotoxicological risk assessment should be performed taking this aspect into account. However, with the amount of new chemicals being produced and the detection limits required it is clear that new integrated indicators are necessary. Limiting the levels of certain chemicals in the environment is one step to improve ecosystem health but alone it will not prevent further deterioration. 8 Due to practical limitations, knowledge on ecotoxicology is only available for a small fraction of the anthropogenic chemical pressure. The importance of this simplification has not been comprehensibly assessed and introduce uncertainty in the appropriate outcome of current legislation and managing practices.JRC.H.5-Rural, water and ecosystem resource

Contribution to the ecology of the Italian hare (Lepus corsicanus)

the italian hare (Lepus corsicanus) is endemic to Central-Southern Italy and Sicily, classified as vulnerable due to habitat alterations, low density and fragmented populations and ecological competition with the sympatric european hare (Lepus europaeus). Despite this status, only few and local studies have explored its ecological features. We provided some key traits of the ecological niche of the italian hare as well as its potential distribution in the italian peninsula. All data derived from genetically validated presences. We generated a habitat suitability model using maximum entropy distribution model for the italian hare and its main competitor, the european hare. the dietary habits were obtained for the italian hare with DnA metabarcoding and High-throughput Sequencing on faecal pellets. The most relevant environmental variables affecting the potential distribution of the italian hare are shared with the european hare, suggesting a potential competition. the variation in the observed altitudinal distribution is statistically significant between the two species.The diet of the Italian hare all year around includes 344 plant taxa accounted by 62 families. The Fagaceae, Fabaceae, Poaceae, Rosaceae and Solanaceae (counts > 20,000) represented the 90.22% of the total diet. Fabaceae (60.70%) and Fagaceae (67.47%) were the most abundant plant items occurring in the Spring/Summer and Autumn/Winter diets, respectively. the Spring/Summer diet showed richness (N = 266) and diversity index values (Shannon: 2.329, Evenness: 0.03858, Equitability: 0.4169) higher than the Autumn/Winter diet (N = 199, Shannon: 1.818, Evenness: 0.03096, Equitability: 0.3435). Our contribution adds important information to broaden the knowledge on the environmental (spatial and trophic) requirements of the Italian hare, representing effective support for fitting management actions in conservation planning

Auditory cortex hypoperfusion: a metabolic hallmark in Beta Thalassemia

Abstract Background Sensorineural hearing loss in beta-thalassemia is common and it is generally associated with iron chelation therapy. However, data are scarce, especially on adult populations, and a possible involvement of the central auditory areas has not been investigated yet. We performed a multicenter cross-sectional audiological and single-center 3Tesla brain perfusion MRI study enrolling 77 transfusion-dependent/non transfusion-dependent adult patients and 56 healthy controls. Pure tone audiometry, demographics, clinical/laboratory and cognitive functioning data were recorded. Results Half of patients (52%) presented with high-frequency hearing deficit, with overt hypoacusia (Pure Tone Average (PTA) > 25 dB) in 35%, irrespective of iron chelation or clinical phenotype. Bilateral voxel clusters of significant relative hypoperfusion were found in the auditory cortex of beta-thalassemia patients, regardless of clinical phenotype. In controls and transfusion-dependent (but not in non-transfusion-dependent) patients, the relative auditory cortex perfusion values increased linearly with age (p < 0.04). Relative auditory cortex perfusion values showed a significant U-shaped correlation with PTA values among hearing loss patients, and a linear correlation with the full scale intelligence quotient (right side p = 0.01, left side p = 0.02) with its domain related to communication skills (right side p = 0.04, left side p = 0.07) in controls but not in beta-thalassemia patients. Audiometric test results did not correlate to cognitive test scores in any subgroup. Conclusions In conclusion, primary auditory cortex perfusion changes are a metabolic hallmark of adult beta-thalassemia, thus suggesting complex remodeling of the hearing function, that occurs regardless of chelation therapy and before clinically manifest hearing loss. The cognitive impact of perfusion changes is intriguing but requires further investigations

Distribution, Fate and Bioaccumulation of Selected Herbicides in the Sacca di Goro Lagoon: Coupled Experimental and Modeling Approaches

Anthropogenic release of chemical contaminants, in particular pesticides, originating from agricultural area of Pianura Padana, significantly impact coastal lagoon ecosystems of the Po River Delta (Galassi et al., 2000; Riparbelli et al., 1996; Baldi et al., 1991; Coppi et al., 1999; Della Vedova et al., 1996; Brown et al., 1996). In particular the Sacca di Goro lagoon, which is one of the most important acquacultural systems in Italy,fish and shellfish production (especially Tapes philippinarum farming) provides work, directly or indirectly, for five thousand people. The Main objective of this study is to provide a useful evaluation tool of Tapes philippinarum exposure to pesticides, especially herbicides, through experimental data and the implementation, development and validation of a pesticide bioaccumulation model. The study has two components: experimental measurement of the levels of contaminants in various environmental compartments as the first step in assessing the exposure, and development of a 3D modelling approach to take into account temporal and spatial variations, which are characteristic of coastal lagoons. The pesticides that are included in this survey have been chosen on basis of several criteria: presence in the study area (literature and experimental data), data volume of sales and presence on the list of priority hazardous substances for the European Community (directive 2000/60/CEE, decision n. 2455/2001/CE). Reference quality standard limits for these substances have been established by the Italian law (Decreto 6 novembre 2003, n. 367, Appendix 2), following the directive 2000/60/CEE, with reference to decision n. 2455/2001/CEE. The model consists of a dynamic mass balance that includes a time-variable chemical transport and fate model for calculating herbicide concentrations in the water column as well as and in sediments based on Farley et al., (1999) model for PCBs in Hudson river and its estuary. In a second step, this model has been coupled with the ecological model already developed for Sacca di Goro (Zaldívar et al., 2003) to analyze the bioaccumulation of herbicides in the food web chain and compare with available experimental results. The bioaccumulation model is based on Thomann, (1989) model of organic chemical distribution in acquatic food chains and Del Vento and Dachs, (2002) model of uptake dynamics of POPs by bacteria and phytoplankton. The present study will provide a quantification of micropollulants fate in a shallow water ecosystem and an estimation of interaction between high-density clam farming and contaminant bioavailability. This project has been developed at the Institute for Environment and Sustainability of the Joint Research Centre (Ispra, VA) in collaboration with the Department of Environmental Science at Parma University.JRC.H.5-Rural, water and ecosystem resource

A Bioaccumulation Model for Herbicides in Ulva Rigida and Tapes Philippinarum in Sacca di Goro Lagoon (Northern Adriatic)

A bioaccumulation model to predict concentrations of s-triazine herbicides in the macroalgae Ulva rigida and in clams Tapes philippinarum has been implemented, calibrated and validated. The model uses input data from a 3D biogeochemical model that provides biomasses in the different compartments, i.e. phytoplankton, zooplankton and bacteria; and from a 3D fate model that provides the herbicides concentrations in the water column as well as in the sediments. Simulated data were compared with experimental data collected during a set of sampling campaigns carried out in 2004 and 2005 in the Sacca di Goro lagoon (Northern Adriatic). The model predicts correctly the concentrations of herbicides measured in Ulva rigida and reproduces with good agreement the values of concentration of herbicides found in clams. Furthermore, the simulated spatial and temporal dynamics in the biota compartment, following those of the water and sediments, are also in agreement with the experimental data. This integrated approach combining biogeochemical, fate and bioaccumulation models provide an overall assessment of the importance of the different environmental compartments and it can also support the testing of different management strategies to improve ecosystem state and functioning. Further research is necessary to elucidate the role and importance of the metabolism of these compounds by clams.JRC.H.1-Water Resource