Using sclerochronology to estimate the growth rate in Pinna nobilis: a case study of Les Alfaques Bay population (Ebro Delta, Spain).

Pinna nobilis is the biggest Mediterranean bivalve, endemic and semi-infaunal. Provide hard substrates to colonize, increasing the spatial heterogeneity of the softbottom communities. P. nobilis suffer a drastic decline due to the anthropogenic pressures. It’s included in the Habitats Directive, in the Barcelona Convention, and in the red lists of many Mediterranean countries. Estimates the growth rate allows to understand the population dynamics of species and yield knowledge to improve protection efforts. In this study a new methodology based on sclerochronology was used to estimate the age and the growth rate of a P. nobilis population located in Les Alfaques bay. The shells of 35 specimens were cataloged. A subsample of 20 individuals was selected, and one valve of each specimens was cut into radial sections along PAMS (Posterior Adductor Muscle Scar) to study the inner register. Thus, the positions of PAMS obscured by nacre were identified, and the number of missing records was estimated by the width of the calcitic layer in the anterior part of the shell. The first growth curve for the Les Alfaques bay population was calculated from the length/age data. To simulate the growth rate of this population, the growth model based on the modified Von Bertalanffy equation was used. Shallow water usually hosts small sized populations of P. nobilis, while in deeper waters specimens reaches larger size. In Les Alfaques bay the population is composed by large size individuals though it’s located in shallows waters. This unusual size pattern is probably due to a sand bar that offers protection from hydrodynamic stress, allowing individuals to elongate more. This study contributes to the knowledge on P. nobilis biology and, with the aim to monitor this species, the growth curve could be used as baseline for future studies on habitat characteristics that may affect the population structure and dynamics in Les Alfaques Bay

Wetland selection, niche breadth and overlap in 10 duck species wintering in northern Campania (Italy)

Analysis of the selection index, the niche breadth and the niche overlap of 10 species of wintering ducks in 11 wetland areas of the Campania region between January 2003 and 2015 revealed that the distribution of the species in the examined sites was not casual. In fact, each species actively chose their wintering area. Using selection index, we were able to measure the species’ preferences and non-preferences for the 11 examined sites. By calculating Shannon-Wiener entropy and its normalized value (Evenness), we determined niche breadth; the Morisita index allowed us to check niche overlap

Modeling macroalgal forest distribution at Mediterranean scale : present status, drivers of changes and insights for conservation and management

Macroalgal forests are one of the most productive and valuable marine ecosystems, but yet strongly exposed to fragmentation and loss. Detailed large-scale information on their distribution is largely lacking, hindering conservation initiatives. In this study, a systematic effort to combine spatial data on Cystoseira C. Agardh canopies (Fucales, Phaeophyta) was carried out to develop a Habitat Suitability Model (HSM) at Mediterranean scale, providing critical tools to improve site prioritization for their management, restoration and protection. A georeferenced database on the occurrence of 20 Cystoseira species was produced collecting all the available information from published and grey literature, web data portals and co-authors personal data. Data were associated to 55 predictor variable layers in the (ASCII) raster format and were used in order to develop the HSM by means of a Random Forest, a very effective Machine Learning technique. Knowledge about the distribution of Cystoseira canopies was available for about the 14% of the Mediterranean coastline. Absence data were available only for the 2% of the basin. Despite these gaps, our HSM showed high accuracy levels in reproducing Cystoseira distribution so that the first continuous maps of the habitat across the entire basin was produced. Misclassification errors mainly occurred in the eastern and southern part of the basin, where large gaps of knowledge emerged. The most relevant drivers were the geomorphological ones, followed by anthropogenic variables proxies of pollution and urbanization. Our model shows the importance of data sharing to combine a large number of spatial and environmental data, allowing to individuate areas with high probability of Cystoseira occurrence as suitable for its presence. This approach encourages the use of this modeling tool for the prediction of Cystoseira distribution and for supporting and planning conservation and management initiatives. The step forward is to refine the spatial information of presence-absence data about Cystoseira canopies and of environmental predictors in order to address species-specific assessments.peer-reviewe

Particle uptake by filter-feeding macrofoulers from the Mar Grande of Taranto (Mediterranean Sea, Italy): potential as microplastic pollution bioremediators

Microplastics (MPs) are a serious threat to the marine environment affecting ecosystem functioning and biodiversity. There is a vast literature about the uptake of MPs at different trophic levels, mainly focused on ecotoxicological effects in commercially relevant species. Little is still known about possible strategies to face MP pollution. Bioremediation is recently gaining attention in this framework. The clearance rate and particle retention of Sabella spallanzanii, Mytilus galloprovincialis, Phallusia mammillata, Paraleucilla magna at three MP concentrations (C1: 1.4 ⋅ 101 p/L; C2: 1.4 ⋅ 102 p/L; C3: 1.4 ⋅ 103 p/L) were investigated to test their potential as MP remover. Digestion protocol removed 98 % of tissues simplifying the MP quantification. P. magna clearance rate decreased with increasing concentration while P. mammillata showed no significant variations. S. spallanzanii and M. galloprovincialis instead exhibited the highest values of clearance rate. Yet, unlike mussels, S. spallanzanii can inhibit particle return to the surrounding water storing them in the tube, resulting to be the best candidate for bioremediation purposes

Il Santo, lo spazio, i miracoli nel Liber Sancti Jacobi

La presenza dello spazio e del paesaggio nei cinque libri del Liber Sancti Jacobi o Codice Callistino sottolinea le grandi distanze, i viaggi di san Giacomo e il suo ruolo nel pellegrinaggio lungo il cammino. Il Libro II, dedicato ai miracoli compiuti dal Santo, contiene riferimenti a luoghi lontani e alle difficoltà del percorso, funzionali a valorizzare la protezione del Santo sui suoi pellegrini.The presence of space and landscape in the five books of the Liber Sancti Jacobi or Codice Callistino underlines the great distances, the journeys of St. James and his role in the pilgrimage along the way. Book II, dedicated to the miracles performed by the Saint, contains references to distant places and the difficulties of the route, functional to value the protection of the Saint on his pilgrims

Metagenomics analysis reveals a new metallothionein family: Sequence and metal-binding features of new environmental cysteine-rich proteins

Metallothioneins are cysteine-rich proteins, which function as (i) metal carriers in basal cell metabolism and (ii) protective metal chelators in conditions of metal excess. Metallothioneins have been characterized from different eukaryotic model and cultivable species. Presently, they are categorized in 15 families but evolutionary relationships between these metallothionein families remain unresolved. Several cysteine-rich protein encoding genes that conferred Cd-tolerance in Cd-sensitive yeast mutants have previously been isolated from soil eukaryotic metatranscriptomes. They were called CRPs for "cysteine-rich proteins". These proteins, of unknown taxonomic origins, share conserved cysteine motifs and could be considered as metallothioneins. In the present work, we analyzed these CRPs with respect to their amino acid sequence features and their metal-binding abilities towards Cd, Zn and Cu metal ions. Sequence analysis revealed that they share common features with different known metallothionein families, but also exhibit unique specific features. Noticeably, CRPs display two separate cysteinerich domains which, when expressed separately in yeast, confer Cd-tolerance. The N-terminal domain contains some conserved atypical Cys motifs, such as one CCC and two CXCC ones. Five CRPs were expressed and purified as recombinant proteins and their metal-binding characteristics were studied. All these CRPs chelated Cd(II), Zn(II) and Cu(l), although displaying a better capacity for Zn(II) coordination. All CRPs are able to confer Cd-tolerance, and four of them confer Zn-tolerance in the Zn-sensitive zrcl a yeast mutant. We designated these CRPs as environmental metallothioneins belonging to a new formerly undescribed metallothionein family. (C) 2016 Elsevier Inc. All rights reserved

Idylle et récits idylliques à la fin du Moyen Âge

Numéro publié avec le concours de   Centre de recherche en histoire européenne comparée (CRHEC), Université Paris-Est Créteil Val-de-Marne MÉTA, EA 4230, Université d’Orléan