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

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

Primer registro de la diatomea Navicula lusoria para México y el Mar Caribe

Knowledge about benthic diatom flora in Mexico is partial and in many regions, among which the Mexican Caribbean stands, studies are lacking. Species belonging to the genus Navicula represent a challenge due to similarity in morphological and morphometric characters coupled with the limited information of morphological variation within populations by environmental changes. The aim of this study is to present the first record of Navicula lusoria to Mexico and the Caribbean Sea providing a description based on light and scanning electron microscopy. Navicula lusoria was observed as epipelic in brackish water in Xel-Há, Quintana Roo, hence, represents the expansion of the distribution range of this species. Although this species can easily be confused with Navicula digitoradiata, the original description of N. lusoria and the typification of N. digitoradiata allow to discriminate both species.En México el conocimiento de la flora de diatomeas bentónicas es parcial y para muchas regiones, entre las que destaca el Caribe Mexicano, prácticamente se carece de estudios. En particular, la determinación de las especies del género Navicula representa un reto debido a la similitud de las especies en sus caracteres morfológicos y morfométricos y a la poca información sobre la variación morfológica intrapoblacional causada por efectos ambientales. El objetivo de este trabajo es dar a conocer el primer registro de Navicula lusoria para México, particularmente para el mar Caribe, proporcionando su descripción con base en microscopia óptica y electrónica de barrido. Navicula lusoria se observó como epipélica en aguas salobres de la caleta de Xel-Há, Quintana Roo; por lo que este registro representa una ampliación del conocimiento sobre el área de distribución del taxon. Aunque esta especie puede ser fácilmente confundida con Navicula digitoradiata, la descripción original de N. lusoria y la tipificación de N. digitoradiata permiten discriminar adecuadamente ambas especies

Macroalgas marinas bentónicas de Isla Gudalupe, Baja California, México

Background. The last floristic survey of marine algae species from Guadalupe Island was published in the 1980s, including a summary of surveys from collections dating back to the beginning of the past century. Goals. To update the species inventory and analyze the macroalgae community on Guadalupe Island. Methods. Four sampling procedures were undertaken, during January, April, and October 2013, and May 2014, from intertidal and subtidal zones, at depths of between 10 and 18m, depending on the locality. Results. 102 species were identified as representatives of the threemain taxonomic divisions; 14 species belonging to Chlorophyta, 29 to Ochrophyta, and 59 to Rhodophyta, related to 39 families and 65 genres. Of the organisms found at a specific level, 30 are new records, 13 are taxonomically synonymous, and 59 correspond to previous registries. The Margalef index shows that the highest biologic richness occurred in May 2014, as while the highest diversity also appeared in that same month, as the Shannon-Wiener index indicates. Data were statistically evaluated with the PERMANOVA analysis, showing statistical differences between the analyzed factors(depth, season, zone, and locality), thus demonstrating high heterogeneity at the localities, mainly between the northern and western areas of the island. Conclusions. Guadalupe Island has high species richness and diversity. In accordance to SIMPER analysis, the species that contribute most to the qualitative differences found in the analyzed factors are Zonaria farlowii, Jania rosea, Sargassum palmeri, Dictyopteris undulata, and Padina durvillei.Antecedentes. El último inventario florístico de algas marinas de Isla Guadalupe se publicó en la década de 1980, e incluye una recopilación de trabajos de colecciones de principios del siglo pasado. Objetivos. Realizar un inventario y un análisis actualizado de la comunidad de macroalgas de Isla Guadalupe. Métodos. Se efectuaron cuatro muestreos durante los meses de enero, abril y octubre del 2013 y mayo del 2014, en la zona intermareal y en la submareal, a 10 y 18 m de profundidad, dependiendo de la localidad. Resultados. En total se determinaron 102 especies, entre las que se encuentran representantes de las tres principales Divisiones taxonómicas: 14 especies de la División Chlorophyta, 29 especies de la División Ochrophyta y 59 especies de la División Rhodophyta, las cuales se relacionan con 39 familias y 65 géneros. De los organismos determinados a nivel específico, 30 corresponden a nuevos registros, 13 con sinonimia taxonómica y 59 especies están previamente registradas. De acuerdo con el índice de Margalef, durante mayo del 2014 se presentó la mayor riqueza biológica, en este mismo periodo, según el índice de Shannon-Wiener, se encontró una mayor diversidad. Los datos se analizaron estadísticamente con el análisis PERMANOVA, el cual mostró diferencias significativas entre los factores examinados de profundidad, temporada, zona y localidad de muestreo, lo que indica una alta heterogeneidad entre las localidades, principalmente entre la zona norte y la oeste de la isla. Conclusiones. Isla Guadalupepresenta una gran riqueza y diversidad biológica. De acuerdo con el análisis SIMPER, las especies que más contribuyen a las diferencias cualitativas de los factores analizados son Zonaria farlowii, Jania rosea, Sargassum palmeri, Dictyopteris undulata y Padina durvillei

Role of age and comorbidities in mortality of patients with infective endocarditis

[Purpose]: The aim of this study was to analyse the characteristics of patients with IE in three groups of age and to assess the ability of age and the Charlson Comorbidity Index (CCI) to predict mortality. [Methods]: Prospective cohort study of all patients with IE included in the GAMES Spanish database between 2008 and 2015.Patients were stratified into three age groups:<65 years,65 to 80 years,and ≥ 80 years.The area under the receiver-operating characteristic (AUROC) curve was calculated to quantify the diagnostic accuracy of the CCI to predict mortality risk. [Results]: A total of 3120 patients with IE (1327 < 65 years;1291 65-80 years;502 ≥ 80 years) were enrolled.Fever and heart failure were the most common presentations of IE, with no differences among age groups.Patients ≥80 years who underwent surgery were significantly lower compared with other age groups (14.3%,65 years; 20.5%,65-79 years; 31.3%,≥80 years). In-hospital mortality was lower in the <65-year group (20.3%,<65 years;30.1%,65-79 years;34.7%,≥80 years;p < 0.001) as well as 1-year mortality (3.2%, <65 years; 5.5%, 65-80 years;7.6%,≥80 years; p = 0.003).Independent predictors of mortality were age ≥ 80 years (hazard ratio [HR]:2.78;95% confidence interval [CI]:2.32–3.34), CCI ≥ 3 (HR:1.62; 95% CI:1.39–1.88),and non-performed surgery (HR:1.64;95% CI:11.16–1.58).When the three age groups were compared,the AUROC curve for CCI was significantly larger for patients aged <65 years(p < 0.001) for both in-hospital and 1-year mortality. [Conclusion]: There were no differences in the clinical presentation of IE between the groups. Age ≥ 80 years, high comorbidity (measured by CCI),and non-performance of surgery were independent predictors of mortality in patients with IE.CCI could help to identify those patients with IE and surgical indication who present a lower risk of in-hospital and 1-year mortality after surgery, especially in the <65-year group

Diversidades alfa y beta de diatomeas epilíticas en oasis de Baja California Sur

IMPRESO Y PD

Estructura de asociaciones de diatomeas en sedimentos del intermareal en la zona

IMPRESO Y PD

Diversidades alfa y beta de diatomeas epilíticas en oasis de Baja California Sur

El 93% de los oasis de la Península de Baja California se encuentran en su porción sur. Algunos de estos han sido evaluados y caracterizados sobre la base de los distintos grupos biológicos. Sin embargo, se ha soslayado el estudio de uno de los grupos taxonómicos autotróficos dominantes en ambientes dulceacuícolas, i. e., las diatomeas. Por lo tanto, el objetivo de este trabajo es determinar las diversidades alfa y beta para seis oasis de Baja California Sur, mediante el primer estudio sistemático de la diatomoflora bentónica (epilítica); con ello se complementa la caracterización de los oasis del Estado. El análisis de diversidad alfa redituó 152 taxa entre especies y variedades, representadas en 55 géneros. La distribución en cuanto a la presencia exclusiva de taxa por oasis fue la siguiente: 26 para San Ignacio, 16 para San Bartolo, 8 para Santa Águeda y 6 para Santiago. De manera combinada, 10 especies son exclusivas para San Ignacio-Santa Águeda y 6 para San Bartolo-Santiago; solamente 11 especies están presentes en 3 de los cuatro oasis mencionados; las especies dominantes son las de afinidad subtropical (oasis) y las cosmopolitas con el 57 y 36% respectivamente. En relación con las variables fisicoquímicas, en particular con el pH, el 62% y 28% de las especies registradas presentan una afinidad alcalófila- circumneutrófila y alcalófila, respectivamente. En cuanto a la diversidad beta, los análisis, tanto cuantitativos como cualitativos, muestran un gradiente latitudinal, por lo que se diferencian grupos o asociaciones representativas de los oasis del Norte (San Ignacio-Santa Águeda) y del Sur (San Bartolo y Santiago). Los análisis de similitud permiten reconocer dos grupos ecológicos basados en la latitud, pH y conductividad. La asociación, al igual que otras, tanto dulceacuícolas como marinas, está representada por pocas (<5) especies dominantes en términos de abundancia y frecuencia, mientras que el grueso está representado por las especies raras. La elevada riqueza y diversidad de la diatomoflora es indicativo de condiciones ambientales favorables (pH, T). La condición subtropical seca de B. C. S., condiciona que más del 50% de los taxa presenten esta afinidad. Abstract Ninety three percent of the oases from the Baja California peninsula are located in its southern portion. Some have been evaluated and characterized on the basis of different biological groups. However, the study of one of the dominant autotrophic taxonomic groups in fresh water, i. e. diatoms, has been neglected. Therefore, the objective of this work is the determination of alpha and beta diversities for six oases of Baja California Sur, through the systematic study of the benthic diatom flora (epilitic); thus complementing the characterization of the oases from Baja California Sur. The alpha diversity analysis yielded 149 taxa represented by 54 genera. The distribution of taxa for each oasis was the following: 26 for San Ignacio, 16 for San Bartolo, 8 for Santa Águeda and 6 for Santiago. In a combined way, 10 species are exclusive for San Ignacio-Santa Águeda and six for San BartoloSantiago; only 11 species are presented in three of the four mentioned oases. The dominant species are those with tropical (57%) cosmopolitan (36%) affinities. In relation with the physical-chemical variables, particularly pH, 62% of the species are alkalophilic-cirumneutrophilic and 28% were alkalophile. The beta diversity analysis showed a latitudinal gradient, in which two groups or assemblages are represented by the Northern (San Ignacio-Santa Águeda) and Southern oases (San Bartolo and Santiago), respectively. The similarity analyses allowed the recognition of ecological groups based on the latitude, pH and conductivity. The oases diatom assemblages, as with other marine and freshwater assemblages, is represented by few (<5) dominant species according to their abundance and frequency, while the majority are represented by rare species. The elevated richness and diversity of the diatom flora is indicative of favorable environmental conditions (pH, Temperature). The subtropicaldry conditions of Baja California Sur, determined that more than 50% of the observed taxa showed this affinity