Matching genetics with oceanography: directional gene flow in a Mediterranean fish species.

Genetic connectivity and geographic fragmentation are two opposing mechanisms determining the population structure of species. While the first homogenizes the genetic background across populations the second one allows their differentiation. Therefore, knowledge of processes affecting dispersal of marine organisms is crucial to understand their genetic distribution patterns and for the effective management of their populations. In this study, we use genetic analyses of eleven microsatellites in combination with oceanographic satellite and dispersal simulation data to determine distribution patterns for Serranus cabrilla, a ubiquitous demersal broadcast spawner, in the Mediterranean Sea. Pairwise population F(ST) values ranged between -0.003 and 0.135. Two genetically distinct clusters were identified, with a clear division located between the oceanographic discontinuities at the Ibiza Channel (IC) and the Almeria-Oran Front (AOF), revealing an admixed population in between. The Balearic Front (BF) also appeared to dictate population structure. Directional gene flow on the Spanish coast was observed as S. cabrilla dispersed from west to east over the AOF, from north to south on the IC and from south of the IC towards the Balearic Islands. Correlations between genetic and oceanographic data were highly significant. Seasonal changes in current patterns and the relationship between ocean circulation patterns and spawning season may also play an important role in population structure around oceanographic fronts.

Stable isotopes and metal contamination in caged marine mussel Mytilus galloprovincialis.

Metal concentrations and isotopic composition were measured in different tissues of the mussel Mytilus galloprovincialis in waters of the Balearic Islands (Western Mediterranean) in order to assess pollution levels. The isotopic composition was correlated with lead, cadmium, selenium and nickel obtained from the digestive gland and foot of the mussels. Significant negative correlations were found between cadmium, selenium and zinc and the mussel foot, mainly for (13)C. Significant correlations were also found between lead and cadmium and the digestive gland. Pearson correlations indicated that the (13)C isotopic signal in foot is a good proxy for the concentration of metals such as lead, cadmium, selenium and zinc. Similarly, (15)N isotopic signatures in the digestive gland reflected the lead and cadmium concentration.

Organic compounds temporal trends at some invertebrate species from the Balearics, Western Mediterranean.

Concentrations of persistent organic pollutants (POPs) such as hexachlorobenzene (HCB), dichlore diphenyl trichloretane (DDT), polychlorinated biphenyls (PCBs), and gamma-hexachlorocyclohexane (gamma-HCH or lindane) were determined in tissue of marine benthic invertebrates such as Mytilus galloprovincialis, Chamelea gallina, Venus verrucosa, Lithophaga lithophaga and Paracentrotus lividus. Species were selected due to their habitat, trophic level, feeding behaviour and their consumption. Invertebrate species were systematically sampled from December 1996 to December 2005 from several sites along the Balearic Islands. The highest concentrations of PCBs (785ng/g lipid) were found in M. galloprovincialis while the lowest concentrations were found in the sea-urchin P. lividus (193ng/g lipid). Among the 7 PCB quantified congeners the higher values are mainly obtained for CB138 and CB153. All bivalves presented higher PCBs contents than the sea-urchin P. lividus are possibly linked with the bioaccumulation process of POPs throughout the food web and to differential detoxifying mechanisms. The concentration of SigmaDDT exceeds that of HCB and gamma-HCH at all species and sampling stations. DDT concentrations ranged from 0.4ng/g ww at the bivalve C. gallina in 2002, to values of 15.8ng/g ww at the bivalve L. lithophaga in 1998. The values obtained for the organic compounds (HCH, HCB, PCBs, DDT) depend upon the place and year of sampling and are compared to values found by other authors for the mussel M. galloprovincialis in other Mediterranean areas. gamma-HCH and HCB were found in lower concentrations than the other POPs.

Scientific management of Mediterranean coastal zone: a hybrid ocean forecasting system for oil spill and search and rescue operations.

The oil spill from Prestige tanker showed the importance of scientifically based protocols to minimize the impacts on the environment. In this work, we describe a new forecasting system to predict oil spill trajectories and their potential impacts on the coastal zone. The system is formed of three main interconnected modules that address different capabilities: (1) an operational circulation sub-system that includes nested models at different scales, data collection with near-real time assimilation, new tools for initialization or assimilation based on genetic algorithms and feature-oriented strategic sampling; (2) an oil spill coastal sub-system that allows simulation of the trajectories and fate of spilled oil together with evaluation of coastal zone vulnerability using environmental sensitivity indexes; (3) a risk management sub-system for decision support based on GIS technology. The system is applied to the Mediterranean Sea where surface currents are highly variable in space and time, and interactions between local, sub-basin and basin scale increase the non-linear interactions effects which need to be adequately resolved at each one of the intervening scales. Besides the Mediterranean Sea is a complex reduced scale ocean representing a real scientific and technological challenge for operational oceanography and particularly for oil spill response and search and rescue operations.

[Evaluation of the utility and efficacy of a day hospital in a gastroenterology department]. / Valoración de la utilidad y eficacia de un hospital de día en un servicio de patología digestiva.

Because public health funds are limited, full advantage should be taken of the resources available. Consequently, hospital stay should be reduced with no loss of health care quality. In our Gastroenterology Department, investigations or treatment requiring a short hospital stay are carried out in a day hospital. Between March 1998 and March 2000, 2,169 patients were treated: 1,862 outpatients and 307 patients referred from another hospital. A total of 95.2% of the outpatients were discharged. Hospital stay was prolonged in 4.8% (91/1,862): 13 due to incomplete investigations, 29 because of worsening of their underlying disease before the procedure and 49 due to complications. The overall complication rate was 2.8% (62/2,169). Six complications developed after discharge; of these two appeared within 24 hours. After the opening of the day hospital, the mean hospital stay in the Gastroenterology Department was reduced from 9.05 days to 6.07 days (p = 0.001). In conclusion, the use of a day hospital in a gastroenterology department is useful, effective, safe and profitable.

Mesoscale vertical motion and the size structure of phytoplankton in the ocean.

Phytoplankton size structure is acknowledged as a fundamental property determining energy flow through 'microbial' or 'herbivore' pathways. The balance between these two pathways determines the ability of the ecosystem to recycle carbon within the upper layer or to export it to the ocean interior. Small cells are usually characteristic of oligotrophic, stratified ocean waters, in which regenerated ammonium is the only available form of inorganic nitrogen and recycling dominates. Large cells seem to characterize phytoplankton in which inputs of nitrate enter the euphotic layer and exported production is higher. But the size structure of phytoplankton may depend more directly on hydrodynamical forces than on the source of available nitrogen. Here we present an empirical model that relates the magnitude of mesoscale vertical motion to the slope of the size-abundance spectrum of phytoplankton in a frontal ecosystem. Our model indicates that the relative proportion of large cells increases with the magnitude of the upward velocity. This suggests that mesoscale vertical motion-a ubiquitous feature of eddies and unstable fronts-controls directly the size structure of phytoplankton in the ocean.

[A consensus on Helicobacter pylori and gastroduodenal pathology]. / Consenso sobre Helicobacter pylori y patología gastroduodenal.

The current debate involving Helicobacter pylori (H.p.) and its potential role as an etiological factor for some digestive diseases, as well as the recent discussion through different mass media of this bacterium, including the American N.I.H. Consensus, have lead to the discussion of the H.p. problem, in order to clarify its real importance in acid-related diseases. Thus we want, as gastroenterologists, to give an overview of the current status, so as to facilitate the general practitioner work when confronted with gastrointestinal diseases, particularly related to H.p. Our purpose is to provide a critical and objective view regarding the implications of H.p. infection, and explain when treatment is needed and how this treatment should be accomplished.