Depth-size trends in western Mediterranean demersal deep-sea fishes

Se discute y argumenta la distribución de los peces en función de su talla. Gráficos, Tallas, Tablas.We analyze the bathymetric trends of demersal deep-sea flshes in the Catalan Sea (NW Medlterranean) between 1000 and 2250 m depth In the first part of the study, only the pattern shown by the whole fauna (wthin-fauna pattern ) 1s considered At 1200 m there is a significant decrease In fish mean welght, as a consequence of the replacement of the dominant large or medium-sized specles by small ones This fauna1 shift may be a consequence of the lower trophic availability at greater depths, as shown by an important decrease in megafaunal biomass between 1000 and 2250 m In the second part, the study focuses on the depth-size trends of the most common species (within-species pattern) Results show that the bigger-deeper phenomenon is not a well-estabhshed tendency None of the lower slope species and only 2 of the 5 middle slope species analyzed behave as bigger-deeper species Moreover some specles which display a bigger-deeper trend in North Atlantic waters do not show any significant trend In the Medlterranean Considering the recent Atlantic origin of Mediterranean ichthyofauna and the contrasting behaviour in the 2 areas, the hypothesis that mean slze increase with depth is the result of inherited ontogenic behaviour can be discarted.Research program BATIMAR (CSICCAICYT; reference PAC 86-008/ID 821).Peer reviewe

Surfactant-Free Synthesis of Polystyrene Nanoparticles Using Oligoglycidol Macromonomers

We investigate the synthesis of functional polystyrene/oligoglycidol particles by surfactant-free emulsion polymerization. Oligoglycidol macromonomers with linear and branched oligoglycidol structure and variable oligoglycidol chain lengths were synthesized. These macromonomers were used as surfmers (surfactants and comonomers) in emulsion polymerization of styrene. Monodisperse colloidally stable polystyrene particles were obtained, decorated with oligoglycidol chains with diameters between 100 and 600 nm. The increase of the macromonomer concentration induced a decrease of the particle size and broadening of the particle size distribution. The macromonomers with branched architecture were more effective and produced monodisperse particles even at low concentrations. Due to the steric stabilization provided by the hydrophilic oligoglycidol layer on the particle surface, the emulsion of polystyrene/oligoglycidol particles obtained exhibited very good resistance against electrolytes. The chemical and enzyme catalyzed grafting polymerization of ε-caprolactone from the polystyrene/oligoglycidol particle surface was demonstrated along with formation of composite particles