Litterfall and mineral return in two cork-oak forests in northeast spain

Seasonal trends in littertall and potential mineral return were studied in two cork-oak forest sites in the northeastern Iberian peninsula. The estimated average litter production was 3.9.M- gy.e1ahar for one site and 4.6 .M- gy.e1ahar for the other; these figures are similar to those reported for holm-oak (Quercus ilex) forests in the same area. Seasonal litterfall patterns were typical of Mediterranean forest ecosystems. Leaves accounted for 46 to 78% of the total dry matter. Their annual weighted-average mineral composition was low in macronutrients (N 8-9; K 4-5; Mg 0.8-1.3; Ca 9-10 and P 0.4-1 m-)g.1g and relatively high in micronutrients such as Mn (2-2.2 m-)g.1g or Fe (0.3-0.4 m)-g..1g Minimum N and P concentrations were found during the growth period. Estimates of potential mineral return for an annual cycle were N 38-52, P 2.1-5.2, K 20-28, Ca 44-53 and Mg 5.4-5.0 k-,g.1ha depending on the site biomass and fertility

Anomalous rainfall and associated atmospheric circulation in the northeast Spanish Mediterranean area and its relationship to sediment fluidization events in a lake

Changes in the dynamics of sediment transport in a Mediterranean lake (sediment fluidization events) are linked to atmospheric circulations patterns (trough monthly precipitation). In the basins of Lake Banyoles, located in the northeast of Spain, water enters mainly through subterranean springs, and associated fluctuations in the vertical migration of sediment distribution (fluidization events) present episodic behavior as a result of episodic rainfall in the area. The initiation of the fluidization events takes place when the monthly rainfall is ∼2.7 times greater than the mean monthly rainfall of the rainiest months in the area, especially in spring (April and May), October, and December. The duration of these events is found to be well correlated with the accumulated rainfall of the preceding 10 months before the process initiation. The rainfall, in turn, is mainly associated with six atmospheric circulation patterns among the 19 fundamental circulations that emerged in an earlier study focused on significant rainfall days in Mediterranean Spain. Among them, accentuated surface lows over the northeast of Spain, general northeasterly winds by low pressure centered to the east of Balearic Islands and short baroclinic waves over the Iberian Peninsula, with easterly flows over the northeastern coast of Spain, are found the most relevant atmospheric circulations that drive heavy rainfall events

On the origin of the North Pacific arcs

We present a new hypothesis that relates global plate tectonics to the formation of marginal basins, island arcs, spreading ridges and arc-shaped mountain belts around the North Pacific Ocean. According to our model, the ellipsoidal-shaped Paleogene basins of the South China Sea, Parece-Vela Basin, Shikoku Basin, Sea of Japan and the Sea of Okhotsk in addition to those of the North American Cordillera can be attributed to the change in plate convergence direction at 42 Ma between the Indoaustralian and Eurasian plates. The new direction of convergence was parallel to the eastern continental margin of Asia and resulted in widespread extension perpendicular to this margin and to the western margin of North America. Both margins form part of a circle parallel to the Indoaustralian-Eurasian direction of convergence.

Short communication. SNP analyses of the 5HT1R and STAT genes in Pacific white shrimp, Litopenaeus vannamei

La industria de la producción de camarón es una de las industrias acuícolas que se encuentra en más crecimiento en la actualidad. Los estudios para encontrar marcadores genéticos son muy efectivos para la mejora de sus propiedades y de gran interés para los productores de camarón. En este trabajo se utilizaron seis individuos de una población de Litopenaeus vannamei, donde se encontraron cuatro polimorfismos de nucleótido único (SNPs) en el gen 5HT1R (5-hidroxitriptamina receptor1) y un SNP en el gen STAT (transductor de señal y activador de la transcripción). Sin embargo, el polimorfismo en el gen STAT resultó ser homocigoto en una población diferente utilizada para análisis de asociación. Los presentes análisis revelaron que el alelo C, en dos polimorfismos SNP (C109T y C395G) del gen 5HT1R, tiende a estar asociado con el aumento del peso corporal. Consideramos que hay necesidad de hacer nuevos estudios utilizando una muestra más amplia y diversa de la población en cuestión.

Seabirds and the circulation of Lyme borreliosis bacteria in the North Pacific

Seabirds act as natural reservoirs to Lyme borreliosis spirochetes and may play a significant role in the global circulation of these pathogens. While Borrelia burgdorferi sensu lato (Bbsl) has been shown to occur in ticks collected from certain locations in the North Pacific, little is known about interspecific differences in exposure within the seabird communities of this region. We examined the prevalence of anti-Bbsl antibodies in 805 individuals of nine seabird species breeding across the North Pacific. Seroprevalence varied strongly among species and locations. Murres (Uria spp.) showed the highest antibody prevalence and may play a major role in facilitating Bbsl circulation at a worldwide scale. Other species showed little or no signs of exposure, despite being present in multispecific colonies with seropositive birds. Complex dynamics may be operating in this wide scale, natural hostparasite system, possibly mediated by the host immune system and host specialization of the tick vector.

Trophic versus geographic structure in stable isotope signatures of pelagic seabirds breeding in the northeast Atlantic

Feeding ecology and geographic location are 2 major factors influencing animal stable isotope signatures, but their relative contributions are poorly understood, which limits the usefulness of stable isotope analysis in the study of animal ecology. To improve our knowledge of the main sources of isotopic variability at sea, we determined δ15N and δ13C signatures in the first primary feather of adult birds from 11 Procellariiform species (n = 609) across 16 northeast Atlantic localities, from Cape Verde (20°N) to Iceland (60°N). Post-breeding areas (where the studied feather is thought to be grown) were determined using light-level geolocation for 6 of the 11 species. Isotopic variability was geographically unstructured within the mid-northeast Atlantic (Macaronesian archipelagos), but trophically structured according to species and regardless of the breeding location, presumably as a result of trophic segregation among species. Indeed, the interspecific isotopic overlap resulting from combining δ15N and δ13C signatures of seabirds was low, which suggests that most species exploited exclusive trophic resources consistently across their geographic range. Species breeding in north temperate regions (Iceland, Scotland and Northern Ireland) showed enriched δ15N compared to the same or similar species breeding in tropical and subtropical regions, suggesting some differences in baseline levels between these regions. The present study illustrates a noticeable trophic segregation of northeast Atlantic Procellariiformes. Our results show that the isotopic approach has limited applicability for the study of animal movements in the northeast Atlantic at a regional scale, but is potentially useful for the study of long-distance migrations between large marine systems

Torrential rainfall in northeast of the Iberian Peninsula: synoptic patterns and WeMO influence

This study presents a catalogue of synoptic patterns of torrential rainfall in northeast of the Iberian Peninsula (IP). These circulation patterns were obtained by applying a T-mode Principal Component Analysis (PCA) to a daily data grid (NCEP/NCAR reanalysis) at sea level pressure (SLP). The analysis made use of 304 days which recorded >100 mm in one or more stations in provinces of Barcelona, Girona and Tarragona (coastland area of Catalonia) throughout the 1950-2005 period. The catalogue comprises 7 circulation patterns showing a great variety of atmospheric conditions and seasonal or monthly distribution. Likewise, we computed the mean index value of the Western Mediterranean Oscillation index (WeMOi) for the synoptic patterns obtained by averaging all days grouped in each pattern. The results showed a clear association between the negative values of this teleconnection index and torrential rainfall in northeast of the IP. We therefore put forward the WeMO as an essential tool for forecasting heavy rainfall in northeast of Spain