18 research outputs found
Fauna coralina de las plataformas mixtas del Paleógeno de las Baleares
Abstract not availabl
A multidisciplinary approach to identify priority areas for the monitoring of a vulnerable family of fishes in Spanish Marine National Parks
Background
Syngnathid fishes (Actinopterygii, Syngnathidae) are flagship species strongly associated with seaweed and seagrass habitats. Seahorses and pipefishes are highly vulnerable to anthropogenic and environmental disturbances, but most species are currently Data Deficient according to the IUCN (2019), requiring more biological and ecological research. This study provides the first insights into syngnathid populations in the two marine Spanish National Parks (PNIA—Atlantic- and PNAC—Mediterranean). Fishes were collected periodically, marked, morphologically identified, analysed for size, weight, sex and sexual maturity, and sampled for stable isotope and genetic identification. Due the scarcity of previous information, habitat characteristics were also assessed in PNIA.
Results
Syngnathid diversity and abundance were low, with two species identified in PNIA (Hippocampus guttulatus and Syngnathus acus) and four in PNAC (S. abaster, S. acus, S. typhle and Nerophis maculatus). Syngnathids from both National Parks (NP) differed isotopically, with much lower δ15N in PNAC than in PNIA. The dominant species were S. abaster in PNAC and S. acus in PNIA. Syngnathids preferred less exposed sites in macroalgal assemblages in PNIA and Cymodocea meadows in PNAC. The occurrence of very large specimens, the absence of small-medium sizes and the isotopic comparison with a nearby population suggest that the population of Syngnathus acus (the dominant syngnathid in PNIA) mainly comprised breeders that migrate seasonally. Mitochondrial cytochrome b sequence variants were detected for H. guttulatus, S. acus, and S. abaster, and a novel 16S rDNA haplotype was obtained in N. maculatus. Our data suggest the presence of a cryptic divergent mitochondrial lineage of Syngnathus abaster species in PNAC.
Conclusions
This is the first multidisciplinary approach to the study of syngnathids in Spanish marine NPs. Habitat preferences and population characteristics in both NPs differed. Further studies are needed to assess the occurrence of a species complex for S. abaster, discarding potential misidentifications of genus Syngnathus in PNAC, and evaluate migratory events in PNIA. We propose several preferential sites in both NPs for future monitoring of syngnathid populations and some recommendations for their conservation.Postprin
Municipal mortality due to thyroid cancer in Spain
BACKGROUND: Thyroid cancer is a tumor with a low but growing incidence in Spain. This study sought to depict its spatial municipal mortality pattern, using the classic model proposed by Besag, York and Mollié. METHODS: It was possible to compile and ascertain the posterior distribution of relative risk on the basis of a single Bayesian spatial model covering all of Spain's 8077 municipal areas. Maps were plotted depicting standardized mortality ratios, smoothed relative risk (RR) estimates, and the posterior probability that RR > 1. RESULTS: From 1989 to 1998 a total of 2,538 thyroid cancer deaths were registered in 1,041 municipalities. The highest relative risks were mostly situated in the Canary Islands, the province of Lugo, the east of La Coruña (Corunna) and western areas of Asturias and Orense. CONCLUSION: The observed mortality pattern coincides with areas in Spain where goiter has been declared endemic. The higher frequency in these same areas of undifferentiated, more aggressive carcinomas could be reflected in the mortality figures. Other unknown genetic or environmental factors could also play a role in the etiology of this tumor
Naturaleza y propiedades de los materiales turbosos de la serie holocénica del río Tajuña (Guadalajara)
Se describen diversas características químicas y paleobotánicas de las capas turbosas incluidas entre los sedimentos calizos cuaternarios del río Tajuña (Guadalajara). Estos depósitos se encuentra constituidos por una mezcla de materia orgánica amorfa muy transformada con una elevada proporción de fino sedimento calizo. Los caracteres más notables de estos materiales son el alto porcentaje de compuestos húmicos extraibles y el gran predominio de los ácidos fúlvicos que, junto con otras características de las capas orgánicas, sugieren un origen reciente y predominantemente alóctono
Precisiones histológicas y bioquímicas acerca de los ejemplares de Frenelopsis procedentes de Torrelaguna (Madrid )
Different morphological features of the Frenelopsis from a Torrelaguna bassin (Madrid, Spain) are described and compared with <i>F. alata</i> and <i>F. oligostomata</i> , studied by other authors. The <i>Frenelopsis</i> rests present, in the studied deposit, a remarkable polymorphism with respect 10 the dimensions of the leaves, but all the specimens studied are greatiy related to <i>F. oligostomata</i> . The chemical study of the organic constituents of the cutic1es shows a heterogeneous composition, being the major constituents an alkali-insoluble cutinized residue and a likehumic acid polyphenolic extractable fraction, Cuticles contains a certain proportion of a highly alterated lignin-like polymer, and minimal amounts of fulvic acids, nitrogenated compounds, free hydrocarbons and carbohydrates. KEY WORDS: Hystology, Biochemistry, Frenelopsis, Upper cretaceous, Palaeobotany, Humic substances.<br><br>Son descritos diferentes aspectos morfológicos de los <i>Frenelopsis</i> del yacimiento de Torrelaguna, comparándose sus características con las descritas por otros autores para las especies <i>F. alata</i> y <i>F. oligostomata</i> . Los restos de <i>Frenelopsis</i> presentan, en el yacimiento estudiado, un notable polimorfismo respecto a las dimensiones del fronde; pero todos los ejemplares descritos poseen características muy similares a las de <i>F. oligostomata</i> . El estudio químico de los constituyentes orgánicos de las cutículas muestra una composición compleja, siendo los componentes mayoritarios un residuo cutinizado insoluble en álcalis y una fracción polifenólica extraíble de características similares a los ácidos húmicos. Los restos presentan una cierta proporción de polímeros similares a la lignina, aunque muy alterada, así como pequeñas cantidades de ácidos fúlvicos, compuestos nitrogenados, hidrocarburos libres y carbohidratos