Species composition and assemblage structure of microfouling diatoms growing on fiberglass plates off the coast of Yucatán, Mexico

Background. It is generally accepted that exopolymer films secreted by diatoms promote the onset of macrofouling on surfaces of materials used in marine environments. However, few studies provide precise information at species level regarding the microfouling process. The use of anti-fouling paints on different surfaces to create a toxic environment may aid in precluding development of the initial diatom microfilm leading to macrofouling. Goals. To describe the species composition and the structure of fouling diatoms. Methods. We analyzed assemblages growing on fiberglass plates, coated and uncoated with antifouling paint, fixed on PVC stands submerged at a 10-m depth. Because diatoms are opportunistic, fast growing microalgae that proliferate on many substrates, our hypothesis was that diatom assemblages growing on fiberglass surfaces, coated or uncoated with antifouling paint, would not differ in their structure. Results. Floristic analysis yielded 170 diatom taxa and similar assemblages with high values of diversity occurring on both surfaces. Conclusions. In keeping with our hypothesis, both colonized fiberglass surfaces compare to living substrata that favor the growth of diatom associations that exhibit high species diversity. This information will be useful in environmental studies, such as pollution abatement, and for the design and maintenance of fishing boats and industrial equipment prone to biofouling.Background. It is generally accepted that exopolymer films secreted by diatoms promote the onset of macrofouling on surfaces of materials used in marine environments. However, few studies provide precise information at species level regarding the microfouling process. The use of anti-fouling paints on different surfaces to create a toxic environment may aid in precluding development of the initial diatom microfilm leading to macrofouling. Goals. To describe the species composition and the structure of fouling diatoms. Methods. We analyzed assemblages growing on fiberglass plates, coated and uncoated with antifouling paint, fixed on PVC stands submerged at a 10-m depth. Because diatoms are opportunistic, fast growing microalgae that proliferate on many substrates, our hypothesis was that diatom assemblages growing on fiberglass surfaces, coated or uncoated with antifouling paint, would not differ in their structure. Results. Floristic analysis yielded 170 diatom taxa and similar assemblages with high values of diversity occurring on both surfaces. Conclusions. In keeping with our hypothesis, both colonized fiberglass surfaces compare to living substrata that favor the growth of diatom associations that exhibit high species diversity. This information will be useful in environmental studies, such as pollution abatement, and for the design and maintenance of fishing boats and industrial equipment prone to biofouling

The optical system of the Tenerife Microwave Spectrometer: a window for observing the 10-20 GHz sky spectra

The TMS optical system is based on a decentered dual-reflector system in a Gregorian configuration to observe with an angular resolution of less than $2^\circ$. The primary goal of the present study is to evaluate the final design and verify that it satisfies the design requirements. We aim for low cross-polarization (-30 dB), low sidelobe (-25 dB) levels, and a stable beam in terms of shape (low ellipticity) and size over a full octave bandwidth (10-20 GHz). We performed both ray-tracing and full-wave simulations using the CST Studio software in order to investigate the system behaviour. We gave special attention to the beam frequency variation and polarization leakage. We have characterized the effects on the radiation pattern produced by the cryostat window. We present the final design of the TMS optical system, as well as a complete study of the system's performance in terms of cross-polarization, sidelobes, ellipticity and beamwidth. We discuss the effects of sidelobes and study the need for a baffle.Comment: 30 pages, 15 figures. Accepted for publication in JINS

A Microwave Blackbody Target for Cosmic Microwave Background Spectral Measurements in the 10-20GHz range

The Tenerife Microwave Spectrometer (TMS) is a ground-based radio-spectrometer that will take absolute measurements of the sky between 10-20 GHz. To ensure the sensitivity and immunity to systematic errors of these measurements, TMS includes an internal calibration system optimised for the TMS band, and cooled down to 4 K. It consists of an Aluminium core, composed of a baseplate and a bed of pyramidal elements coated with an absorber material and a metallic shield. The absorber coating is made of a commercial resin ECCOSORB CR/MF 117. To achieve the high stability (+/- 1 mK/h), temperature homogeneity (thermal gradients {AT = 0.999) requirements of the reference unit, careful consideration has been given to the RF and thermal properties of the materials, as well as their geometry. In summary, this paper presents a comprehensive account of the design, characterisation, and test results of the TMS reference system.Comment: 45 pages, 36 figures, JINS

Distribución y estructura de comunidades de diatomeas en sedimentos de un sistema de manglar

The structure of diatom communities from the sediments bordering the mangrove forest was determined for two periods (cool and warm) in five sites of Zona de Canales, and in a sixth site in the San Carlos area within the Magdalena-Almejas lagoon system. 325 taxa were identified at the species, variety and form levels. The greater number of species were represented within the genera: Navicula (33), Amphora (31), Nitzschia (26), Cocconeis (16) y Lyrella (15). The surveyed communities are composed mainly by a mixture of episammic and epipelic taxa. The distribution of dominant (highly) abundant and abundant species was very much continuous, in both periods and sampling sites. Out of the 24 most important taxa in terms of their abundances and frequencies (BVI), eight occurred in both periods. Diversity values (H y 1-?) were high in the six sampling sites during the two periods and showed no significant differences (? = 0.05) by site or date of sampling. Although the San Carlos site did not vary significantly from Zona de Canales (ZC) sites, in terms of diversity, it does in its species composition. The absence of Lyrella and Mastogloia species from this site, while being conspicuous in ZC is underlined. The diatom assemblages in the mangrove sediments of ZC in Bahía Magdalena are characterized by high species richness and diversity, homogeneously distributed, both temporally and spatially.Se determinó la estructura de las comunidades de diatomeas en los sedimentos adyacentes al manglar, para dos períodos del año (frío y cálido), en cinco sitios de Zona de Canales dentro del Sistema Lagunar MagdalenaAlmejas, más uno, apartado, en el área de San Carlos. Se reconocieron un total de 325 taxa, a niveles de especie, variedad y forma. El mayor número de especies estuvo representado dentro de los géneros: Navicula (33), Amphora (31), Nitzschia (26), Cocconeis (16) y Lyrella (15). Las comunidades de diatomeas estuvieron compuestas principalmente por una mezcla de taxa episámicos y epipélicos. La distribución de las especies dominantes (muy abundantes) y abundantes resultó casi continua en los sitios de muestreo y en ambos periodos. De los 24 taxa más importantes numéricamente (IVB), ocho se presentaron en ambos períodos. Los valores de diversidad (H y 1-?) fueron elevados en los seis sitios de muestreo en ambos períodos y no variaron significativamente (? = 0.05) por sitio o fecha de muestreo. Aunque un sitio (San Carlos) no varió significativemente de los otros (Zona de Canales) en cuanto a diversidad, si difirió en la composición de especies. Destacó la ausencia de especies de Lyrella y Mastogloia en dicho sitio, mismas que fueron características de Zona de Canales. Las comunidades de diatomeas de sedimentos de manglar de Zona de Canales de Bahía Magdalena se distribuyen homogéneamente, espacial y temporalmente, y se caracterizan por una elevada riqueza y diversidad de especies

Biovolumen ponderado; índice para estimar la contribución de especies en asociaciones de diatomeas bentónicas

With the purpose of deriving an alternative way for assessing the contribution of diatom taxa in benthic assemblages to biomass, the weighed biovolume index (WBV) is here proposed. The biovolumen (BV) was computed for taxa collected from intertidal mangrove sediments. The taxa were selected on the basis of total abundances (TA) and linear size. The TA and BV values showed an apparent inverse relation. In this way, the combined use of these variables is proposed (as WBV) as a more precise approximation to the contribution (as biomass) of each taxon in the assemblage. Thus, the WBV is computed as the product of the total abundances (TA) times the BV for each taxon, divided by the ? BV(AT) of all the taxa in the sample and expressed as percentage.Se propone el uso del biovolumen ponderado (BVP) de cada taxón, como una alternativa para medir la contribución a la biomasa, de los distintos taxa de diatomeas bentónicas de una asociación. Se determinó el biovolumen (BV) de taxa provenientes de sedimentos del intermareal en una zona de manglar; los taxa se seleccionaron con base en sus abundancias y su tamaño lineal. Los valores de BV y abundancia total (AT) mostraron una aparente relación opuesta. Consecuentemente, se propone el uso combinado de las AT y BV, en la forma de BVP, como mejor aproximación a la contribución (biomasa) de cada taxón en la asociación. Así, se definió el BVP como el producto del BV de un taxón por su abundancia, sobre la ? BV(AT) de todas las especies en la muestra, expresado en porcentaje

Composición y estructura de la comunidad de moluscos de fondos blandos de la isla Santa Cruz, golfo de California, México

Background. In the marine environment of San Cruz Island, no published references exist regarding the ecology of soft-bottom mollusks. Thus, it is important to carry out research that broadens and deepens the knowledge of this marine area and contributes to proposals of management methods and alternatives for the sustainable use of insular marine resources. Goals. This study seeks to characterize the community composition and structure of soft-bottom mollusks of the infralitoral zone of Santa Cruz Island, and describe some of the characteristics associated with their habitat. Methods. During August 2010, 32 samples were collected: 16 were biological samples and 16 were sediment samples. The composition, abundance, and diversity of the malacological community were analyzed using ecological indexes. Results. 695 individuals were recorded and grouped in two classes: Gastropoda with 446 organisms (5 orders, 11 families, and 19 species); the most abundant species was Siphonaria maura (18%); the class Bivalvia included 249 organisms (8 orders, 14 families, and 25 species); the most abundant species was Tellina eburnea (10%). The Gastropoda class were more abundant than the Bivalvia, i.e., 64.17% and 35% respectively. The species with major abundances and relative frequencies were the gastropods Siphonaria maura (18%) and the bivalve Septifer seteki (69%). Four trophic categories were identified: filterers (73%), herbivores (20%), carnivores (5%), and ectoparasites, the latter of which were the rarest group (2 %). Conclusions. At this site, the specific richness (44 taxa) was lower compared to other sites from different latitudes of the western Gulf of California, likely derived from the higher energy environment of the study area that allowed only juvenile mollusks and micromollusks to be collected.  Antecedentes. Respecto al ambiente marino de la isla Santa Cruz, no existen trabajos publicados de ecología de las especies de moluscos de fondos blandos, por lo que es importante realizar investigaciones que amplíen y profundicen el conocimiento de la zona marina y contribuyan a plantear métodos de manejo y alternativas de uso sustentable de los recursos marinos insulares. Objetivos. El presente trabajo pretende caracterizar la composición y estructura de la comunidad de los moluscos de fondos blandos de la zona infralitoral de la isla Santa Cruz y describir algunas características asociadas con su hábitat. Métodos. En agosto de 2010 se recolectaron 32 muestras, 16 biológicas y 16 de sedimentos. Se analizó la composición, abundancia y diversidad de la comunidad béntica malacológica mediante indicadores ecológicos. Resultados. Se registraron 695 ejemplares agrupados en dos clases, Gastropoda: 446 organismos (cinco órdenes, 11 familias y 19 especies), entre los cuales la especie más abundante fue Siphonaria maura (18%); y Bivalvia: 249 organismos (ocho ordenes, 14 familias y 25 especies), donde la especie más abundante fue Tellina eburnea (10%). La clase Gastropoda fue mayor (64.17%) que Bivalvia (35.82%). Las especies con mayor abundancia y frecuencia relativa fueron el gastrópodo Siphonaria maura (18%) y el bivalvo Septifer zeteki (69%). Se encontraron cuatro categorías tróficas: filtradores (73%), herbívoros (20%), carnívoros (5%) y ectoparásitos (2%). Conclusiones. En este sitio, la riqueza específica (44 taxones) fue menor en comparación con otros sitios de diferente latitud en el golfo de California occidental, posiblemente debido a que la zona de estudio es un ambiente de alta energía donde sólo se encontraron juveniles de moluscos y micromoluscos

Variación espacial de ensambles de moluscos bentónicos de fondos blandos del archipiélago Espíritu Santo, golfo de California, México

Background. The Espiritu Santo archipelago is recognized for its high biodiversity as a national park. Studies carried out on soft-bottom mollusks are of the faunistic type, and little is known about the variations in their community structure. Objective. To know the composition and the spatial variation in the structure of the assemblages of soft-bottom mollusks of the archipelago and to describe the possible incidence of the type of substrate in their structuring. Methods. In the infralittoral zone, 66 sampling sites were distributed in nine locations. The mollusks were collected by autonomous diving using a 1 m-2 metal frame and a nucleator to analyze of the sediment texture. The medium-grained sand substrate presented the highest distribution. The ecological indices of abundance, species richness (S), Shannon-Wiener diversity (H´), and Pielou evenness index (J´) were estimated. Results. 23,743 individuals were quantified, belonging to 102 species distributed in three classes, 17 orders, 39 families, and 70 genera. The bivalves were represented by 48 species, 9 orders, 17 families, and 39 genera. The gastropods by 52 species, 7 orders, 21 families and 30 genera, and the scaphopods by 1 species. Significant differences were found between localities for species richness and diversity but not for species equity. Conclusions. Spatial variations were observed in the structure of the mollusks assemblages in the archipelago, which could be due to the combined effect of the sediment texture and the presence of mangroves existing in some locations.Antecedentes. El Parque Nacional Archipiélago Espíritu Santo es reconocido por su elevada biodiversidad. Los estudios realizados sobre los moluscos de fondos blandos son inventarios faunísticos, y se conoce poco sobre la variación de su estructura comunitaria. Objetivo. Conocer la composición y la variación espacial en la estructura de los ensambles de moluscos de fondos blandos de este archipiélago y describir la posible relación con el tipo de sustrato. Métodos. En la zona infralitoral se distribuyeron 66 sitios de muestreo en nueve localidades. La colecta de moluscos se realizó mediante buceo autónomo utilizando un marco metálico de 1m2 y para el análisis de la textura del sedimento un nucleador. Se estimaron los indicadores estructurales de abundancia (N), riqueza de especies (S) y los índices de diversidad de Shannon-Wiener (H´) y de Equidad de Pielou (J´). Resultados. El sustrato de arena de grano medio presentó la mayor contribución. Se cuantificaron 23 743 organismos, registrados en 102 especies distribuidas en tres clases, 17 órdenes, 39 familias y 70 géneros. Los bivalvos estuvieron representados por 48 especies, 39 géneros, 17 familias y nueve órdenes. Los gastrópodos por 52 especies, 30 géneros, 21 familias y siete órdenes y los escafópodos por una especie. Se encontraron diferencias significativas entre las localidades para la riqueza de especies y diversidad, pero no para equidad. Conclusiones. Se observaron variaciones espaciales en la estructura de los ensambles de moluscos en el archipiélago, las cuales pudieron ser debidas al efecto combinado de la textura del sedimento y a la presencia de mangles en algunas localidades

La pesquería de la almeja chocolata Megapitaria squalida (Bivalvia: Veneridae) en Baja California Sur, México

The Squalid Callista Megapitaria squalida is one of the most important bivalve fisheries in Baja California Sur. However, there is scarce information about the current state of the fishery. In order to obtain an overview of the fishery development, spatial and temporal catch trends were analyzed. The analysis was based on monthly and by area catches records from 1999 to 2006. Results show six major fishing areas: La Paz Bay, Ojo de Liebre Lagoon, Magdalena Bay, San Ignacio Lagoon, Loreto and Santa Rosalía. In the first three areas it was observed 96% of the total catch. There was a general increase in catches from 1992 (315 t) to 2002 (1,128 t) due to the catch increase in Ojo de Liebre Lagoon and La Paz Bay. However, a substantial catch decline occurred in Magdalena Bay from 2001 (457 t) to 2006 (73 t). Since 2002 there has been a general catch decline. Therefore, the conclusion of the study affirms that the fisheries in La Paz Bay and Ojo de Liebre Lagoon are at their maximum level of exploitation. In Magdalena Bay there is evidence of overfishing, while San Ignacio Lagoon, Loreto and Santa Rosalía could have developing potential. A detailed stock assessment is recommended due to the recent negative catch trends that could indicate an excessive fishing pressure.La almeja chocolata Megapitaria squalida representa una de las pesquerías de bivalvos más importantes en Baja California Sur. Sin embargo, poco se sabe sobre el estado actual de esta pesquería. Con el objetivo de obtener una perspectiva del desarrollo de la pesquería, se analizaron las tendencias espacio-temporales de las capturas, utilizando los registros de producción mensual y por localidad de 1999 a 2006. Los resultados muestran seis regiones de pesca importantes: Bahía de La Paz, Laguna Ojo de Liebre, Bahía Magdalena, Laguna San Ignacio, Bahía de Loreto y la costa de Santa Rosalía. En las tres primeras se obtuvieron 96% de las capturas totales. Se observó un incremento en la producción de 1992 (315 t) a 2002 (1,128 t) debido al aumento en la Laguna Ojo de Liebre y Bahía de La Paz, sin embargo es notable la disminución de las capturas en Bahía Magdalena desde el 2001 (457 t) al 2006 (73 t). A partir de 2002 se observó una disminución general de las capturas. Se concluye que la pesquería en Bahía de La Paz y Laguna Ojo de Liebre se encuentra en su máxima capacidad, en Bahía Magdalena hay indicios de sobreexplotación, mientras que en Laguna San Ignacio, Bahía de Loreto y Santa Rosalía podría haber potencial de desarrollo. Se recomienda profundizar en la evaluación del recurso, debido a que las tendencias de disminución de las capturas observadas en los últimos años, pueden estar indicando una excesiva presión de pesca

Título: Por el libro de la muger fuerte, Doña Maria Vela, respondiendo a las dudas que se han puesto en èl y en el espiritu y vida de la Santa

Copia digital. Valladolid : Junta de Castilla y León. Consejería de Cultura y Turismo, 2009-2010Marca de ed. en ambas port.Texto a dos col. con apostillas marginalesHojas escritas por ambas carasSign.: [calderón]8, 2[calderón]2,A-Z8, 2A-H8, 2I4Esc. xil.Del maestro Fray Angel Manrique ... Por el libro de la muger fuerte, Doña Maria Vela respondiendo a las dudas que se han puesto en el y en el espiritu y vida de la Santa : p. 198-248, con port. propi