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This preprint has been peer-reviewed and recommended by Peer Community in Evolutionary Biology (PCI Evol Biol, doi: 10.24072/pci.evolbiol.100056). Diverging semi-isolated lineages either meet in narrow clinal hybrid zones, or have a mosaic distribution associated with environmental variation. Intrinsic reproductive isolation is often emphasized in the former and local adaptation in the latter, although both can contribute to isolation. Rarely these two patterns of spatial distribution are reported in the same study system. Here we report that the long-snouted seahorse Hippocampus guttulatus is subdivided into discrete panmictic entities by both types of hybrid zones. Along the European Atlantic coasts, a northern and a southern lineage meet in the southwest of France where they coexist in sympatry with little hybridization. In the Mediterranean Sea, two lineages have a mosaic distribution, associated with lagoon-like and marine habitats. A fifth lineage was identified in the Black Sea. Genetic homogeneity over large spatial scales contrasts with isolation maintained in sympatry or close parapatry at a fine scale. A high variation in locus-specific introgression rates provides additional evidence that partial reproductive isolation must be maintaining the divergence. Surprisingly, fixed differences between lagoon and marine populations in the Mediterranean Sea belong to the most differentiated SNPs between the two Atlantic lineages, against the genome-wide pattern of structure. These parallel outlier SNPs cluster on a single chromosome-wide island of differentiation. Since Atlantic lineages do not match the lagoon-sea habitat variation, genetic parallelism at the genomic island suggests a shared genetic barrier contributes to reproductive isolation in contrasting contexts -i.e. spatial vs. ecological. We discuss how a genomic hotspot of parallel differentiation could have evolved and become associated either with space or with a patchy environment in a single study system.

14 pages, 9 figures, 1 table, The bacterial community in coastal waters of northeastern Adriatic Sea was dominated by SAR11 and Sulfitobacter taxa throughout the year. The seasonal distribution of bacterioplankton taxa showed continual differences between surface (0 m) and bottom (27 m) layers. The surface assemblage was represented by Actinobacteria, Cyanobacteria, Alphaproteobacteria, and Gammaproteobacteria, while the bottom assemblage was made up of Bacteroidetes, Cyanobacteria and Alphaproteobacteria. As SAR11 was more dominant in the bottom layer, its appearance may be linked to northward transport of oligotrophic waters of higher salinity from the south. Gammaproteobacteria appeared only in the surface layer during summer, influenced by higher amounts of nutrients, brought in by the Po River. Synechococcus was the most abundant taxon at the genus level. Dominance of Synechococcus during the whole season agrees with its dominance in terms of abundance determined by flow cytometry, and confirms its utmost importance in the picoplankton community of this area. We found two different types of Synechococcus: one type with high similarity to Synechococcus CC9902, present in the surface and bottom layers, and another one similar to Synechococcus WH7803, present only in the surface layer. Oligotrophic conditions together with complex hydrological features of this area were reflected in diversification and dynamic shifts of surface and bottom assemblages, This work was supported by Croatian project 098-0982705-2729 and UKF Grant Agreement No. 70/10. S. Orlic is grateful to the Croatian Science Foundation (BABAS project). The work in Barcelona was supported by grant GEMMA (CTM2007-63753-C02-01/MAR) from the Spanish Ministry of Science and Innovation

International audience; Oxidation of microparticles of lutetium (bis-tert-butylphthalocyaninato) complex immobilized on the surface of paraffin-impregnated graphite electrode and immersed into an aqueous electrolyte was investigated by cyclic voltammetry and square wave voltammetry. The electrode reaction exhibits the typical features of insertion electrochemistry where the anions of the aqueous electrolyte are transferred into the solid phase upon oxidation of the redox centers there in. The reaction is quasi-reversible and influenced by the ohmic resistance of the compound. The formal potentials of the electrode reaction involving the transfer of perchlorate, nitrate, and chloride ions follow the same order as the Gibbs energies of ion transfer in the systems water–nitrobenzenene and water–octanol. Bromide and thiocyanate ions are not intercalated.

Trace elements and organic carbon inputs to the Mediterranean Sea from an urbanised area (Marseille City) were studied and characterised during flood events. Inputs were brought to the sea by two small coastal rivers whose waters were mixed together and also with treated wastewaters (TWW) just before discharge. The monitoring of the rivers during flood events showed the high temporal dynamics of water flow, suspended particulate matter (SPM), organic carbon and trace metals concentrations, typical of small coastal Mediterranean rivers and requiring an appropriate sampling strategy. Dissolved/particulate partition coefficient (log Kd ) in rivers during floods remained quasi-constant for a given trace element, but differed from one element to another according to their affinity toward particles. Because of high SPM concentrations, trace elements were mainly brought to the sea during floods as particles, despite a weaker affinity for particles when compared to baseflow conditions for all studied elements but Pb. If the contribution of TWW dominated the elements baseflow discharge to the coastal zone, rivers outweighed during floods. When discharged to the sea, most trace elements underwent partial desorption in the salinity gradient, especially at highest salinity. Laboratory desorption experiment results were consistent with field data and showed slower desorption kinetics than in baseflow conditions, suggesting that trace elements desorption rates from particles are slower than sedimentation rates. With regard to heavy particles, it results in a potential impact of the sediment on benthic organisms and a possible further desorption after sediment resuspension events. With regard to light particles, it results to a possible additional desorption during offshore transport.