The Relationship of Sediment and Intersitial Water Properties with Mangrove Health in a Subtropical Coastal Lagoon of Mexico

The aim of this study was to determine the influence of the physicochemical properties of interstitial water, sediment geochemistry and sediment grain size on the health of mangroves in three Basins (I, II and III) in Cuyutlán Lagoon, Mexico. Monthly sampling was conducted at eight stations from February to October 2014. The optimum reforestation conditions were observed at stations in Basin I (1A and 1B) and II (2C and 2D), where exchange of water between the ocean and lagoon predominates (Tepalcates and Ventanas Channels) and tidal influence induces water exchange that generates increased dissolved oxygen (3–4 mg/l) concentrations, low salinity (20–30) and greater coverage of healthy mangrove, with sufficient organic carbon (4–6%) for assimilation by the plants. By contrast, stations in Basin III were characterised by water stagnation resulting in increased salinity (40–50), depletion of the dissolved oxygen concentrations (0.1–2 mg/l) and low organic carbon (2%) in sediments, which contributed to low dwarf mangroves with low coverage most likely in response to environmental stress. Finally, the healthiest mangrove was found in areas where the dynamics favoured the deposition of organic carbon and medium sands in the sediment, which generated greater nutrient availability for fixation and assimilation by the roots

Desarrollo de sondas para la detección de Pseudo-nitzschia delicatissima en la costa Catalana, España: estudios preliminares

Este trabajo recoge los actuales avances sobre el desarrollo de sondas moleculares para la hibridación fluorescente in situ (FISH) y PCR en tiempo real como métodos de detección de Pseudo-nitzschia delicatissima.Este trabajo ha sido financiado por el projecto RTA-2005-00109-00- 00, INIA. El trabajo de E. Garces está financiado por el contrato Ramon y Cajal del Ministerio de Educación y Ciencia. Sonia Quijano está financiada por una Beca PROMEP, México

Caracterización del género Pseudo-nitzschia en la Costa Catalana

Memoria de tesis doctoral presentada por Sonia Isabel Quijano Scheggia para optar al grado de Doctora por la Universitat Politècnica de Catalunya (UPC), realizada bajo la dirección de la Dra. Esther Garcés i Pieres del Institut de Ciències del Mar (ICM-CSIC).-- 169 pagesLas diatomeas son el grupo de microalgas más abundante y diversificado, con más de 200.000 especies reconocidas (Mann, 1999). En el ambiente marino forman parte del fitoplancton con más de 18 mil especies (Fryxell y Hasle, 2003) y son responsables de proliferaciones estacionales recurrentes en zonas costeras (Margalef, 1991; Falkowski et al., 1998). Como todos los organismos autotróficos, contienen clorofila y pigmentos adicionales para capturar la energía del sol, y mediante la fotosíntesis producen compuestos carbonados y oxígeno. Son las mayores fuente de oxígeno en el planeta, produciendo un equivalente al de toda la selva húmeda tropical (Field et al., 1998). Además son responsables de entre el 40% al 45% de la producción primaria global de compuestos orgánicos en el océano (Mann, 1999). Las diatomeas pertenecen taxonómicamente a la división Heterokontophyta, clase Bacillariophyceae. Se caracterizan por tener una cubierta de sílice en forma de caja formada por dos valvas que se denomina la frústula. Se diferencian en cuanto a la morfología de las valvas en dos grandes grupos: las centrales con simetría radial, y las pennadas con simetría bilateral (Round et al., 1990). [...]Esta tesis doctoral se ha llevado a término en el Institut de Ciències del Mar de Barcelona (CSIC) con una beca predoctoral del programa PROMEP del Gobierno de México (Secretaria de Educación Pública) y la Universidad de Colima. La tesis se ha enmarcado dentro del proyecto: "Programa de Vigilancia del fitoplancton tòxic i nociu en les aigües del litoral català" realizado mediante convenio entre el "Institut Ciències del Mar (CSIC) i la Agència Catalana de l'Aigua de la Generalitat de Catalunya"Peer Reviewe

Morphology, physiology, molecular phylogeny and sexual compatibility of the cryptic Pseudo-nitzschia delicatissima complex (Bacillariophyta), including the description of P. arenysensis sp. nov.

18 pages, 34 figures, 5 tablesSeveral strains of Pseudo-nitzschia delicatissima were isolated from the northwestern Mediterranean Sea and compared using light and electron microscopy, phylogenetic analyses of internal transcribed spacer rDNA, together with studies of their mating system, estimations of growth rates and reduction in cell size with time. Morphological and phylogenetic analyses identified all strains as Pseudo-nitzschia delicatissima, but in the phylogenetic analyses they fell into two genetically distinct clades. Studies of fine structural morphological characteristics by electron microscopy did not allow discrimination of the two clades. Mating experiments showed successful sexualisation among strains of clade B/1; whereas, mating attempts in clade A/2 and between clade A/2 and clade B/1 were unsuccessful under the examined laboratory conditions. The morphological characteristics of the daughter generations F1 and F2 were analyzed and abnormalities in the F2 generation described. We describe for the first time the rapid size reduction in the F2 generation. Culture studies showed physiological differences between the two clades; strains from clade A/2 showed a tendency for higher growth rates and slower reduction in cell size than strains from clade B/1. Morphological and phylogenetic studies comparing strains from different parts of the world showed P. delicatissima as a cryptic species complex comprising at least two different genotypes, both apparently cosmopolitan. The two genotypes were shown to occur sympatrically in the Mediterranean Sea, and we hypothesize that the genotypes were most likely separated by reproductive barriers associated with sexualisation occurring at different temperatures and hence different seasons. The molecular and physiological differences allow us to describe one of the genotypes, clade B/1, as a new species, Pseudonitzschia arenysensis sp. nov. Differences in growth capabilities of the cultures were observed in relation to cell size and physiological status and showed a nonlinear relationship between cell size and growth. Possibly, such capability plays a key role in the occurrence and dynamics of phytoplankton algae.This study was supported by the European Union–funded Integrated Infrastructure Initiative grant SYNTHESYS, the EC funded Research Project SEED (Life cycle transformations among HAB species, and the environmental and physiological factors that regulate them) GOCE-CT-2005-003875 and the CRA (Centre de Referencia en Aquicultura, CIRIT-Generalitat de Catalunya, Spain).Peer reviewe

Diversidad marina escondida

2 páginas, 4 figuras.El número de especies se ha subestimado en el grupo de las diatomeas debido a la dificultad que entraña diferenciar una especie de otra.Peer reviewe

First detection of diatom Pseudo-nitzschia brasiliana (non toxic) and its relative P. multistriata (presumably toxic) in the NW Mediterranean Sea

1 pageDiatoms of the genus Pseudonitzschia are widely distributed in seas and oceans. They attract world wide interest since they were found to produce the lethal neurotoxin domoic acid (DA). Back in 1987, a member of this genus (P. multiseries) caused amnesic shellfish poisoning (ASP) in eastern Canada [1]. Production of DA is reported for at least ten species of Pseudo-nitzschia [2], and their blooms result in marked toxin accumulation through the food chains, with subsequent impacts on individual marine organisms, total ecosystems, humans, and even the economy [3]. In the Mediterranean, both Pseudonitzschia galaxiae and P. multistriata were shown to be toxic [4]. [...]Peer Reviewe

Dinámica de las proliferaciones del género Pseudo-Nitzschia en dos bahías costeras (NO del Mar Mediterráneo)

14 pages, 9 figures, 5 tables[EN] The spatial and temporal variations in the composition of Pseudo-nitzschia during bloom events from August 2005 to February 2006 were characterised in two bays of the NW Mediterranean Sea (Alfacs and Fangar Bay) by means of scanning electron microscopy (SEM). The study provides detailed records of the Pseudo-nitzschia community at the species level and describes its relationship with both the surrounding environmental conditions and biotic factors such as the accompanying phytoplankton community. The size distributions of several species of Pseudo-nitzschia were monitored during the bloom events. These measurements may serve as indicators of the physiological status of the cells. The species observed in the two bays were Pseudo-nitzschia calliantha, P. delicatissima, P. fraudulenta, P. multistriata, and P. pungens. In Alfacs Bay, a mixed species bloom of P. calliantha and P. delicatissima began in late August 2005 and lasted 11 weeks. In Fangar Bay, the Pseudo-nitzschia bloom was limited to the period from early August to late September 2005 and comprised P. calliantha and P. delicatissima. Commonly, the proliferation of Pseudo-nitzschia was mono-specific or was accompanied by other diatoms. Two objectively defined groups were identified by the statistical analysis in Alfacs bay; the first was made up only of winter samples and the second of summer and autumn samples. The first group was defined by a high concentration of NO3¯ and low concentrations of NH4+, conditions associated with a high abundance of P. delicatissima and a low abundance of P. calliantha. The second group expressed the opposite characteristics. A succession of different blooming species of Pseudo-nitzschia lasting months in Alfacs Bay is described[ES] Las variaciones en la composición de una proliferación de Pseudo-nitzschia se caracterizaron de agosto 2005 a febrero 2006 en dos bahías del Mediterráneo noroeste (bahía de Alfacs y Fangar) por medio de microscopia electrónica de barrido (SEM). Este estudio provee descripciones detalladas de la comunidad de Pseudo-nitzschia hasta nivel de especie y describe las relaciones con las condiciones ambientales y factores bióticos como por ejemplo la comunidad fitoplanctónica acompañante. La distribución de tamaño de algunas especies de Pseudo-nitzschia fue estudiada durante el evento de proliferación y se propone como posible indicador del estado fisiológico de las células. Las especies observadas en las dos bahías fueron Pseudo-nitzschia calliantha, P. delicatissima, P. fraudulenta, P. multistriata y P. pungens. En la bahía de Alfacs una proliferación mixta de P. calliantha y P. delicatissima comenzó en agosto 2005 y duró 11 semanas. En la bahía de Fangar la proliferación de Pseudo-nitzschia estuvo limitada al periodo entre principios de agosto y fines de septiembre. Normalmente las proliferaciones de Pseudo nitzschia fueron monoespecíficas o acompañadas de otras diatomeas. Mediante el análisis estadístico de los datos en la bahía de Alfacs, se definieron dos grupos de muestras: las de invierno y las de veranootoño. El primer grupo se definió por la alta concentración NO3 ¯ y baja concentración de NH4 +, condiciones que acompañaron una gran abundancia de P. delicatissima y baja abundancia de P. calliantha. El segundo grupo presentó las características opuestas. Se describe la sucesión de especies de Pseudo-nitzschia que proliferaron durante meses en la bahía de AlfacsThis study was funded by ACA (Departament de Medi Ambient, Generalitat de Catalunya), CSIC, through the contract “Plà de vigilància de fitoplàncton nociu i tòxic a la Costa Catalana”, Direcció General de Acció Marítima (Generalitat de Catalunya), through the monitoring programme on shellfish harvesting areas and the EC-funded Research Project SEED, GOCECT- 2005-003875. S. Quijano-Scheggia’s work was supported by a PROMEP grant, Universidad de Colima, México. E. Garcés’s work was sustained by a Ramon y Cajal contract from the Spanish Ministry of Science and Education. We also thank the Programa de seguiment de la qualitat de les aigües, mol.luscs i fitoplancton tòxic a les zones de producció de marisc del litoral català de la DGPIAM and the Xarxa de Referència de Recerca i Desenvolupament en AqüiculturaPeer reviewe

Infestación de la Diatomea Roperia tesselata por el Nanoflagelado Parásito Pirsonia sp en las Bahías de Manzanillo, Colima México

XVII Congreso Nacional de Oceanografía, 11-14 de septiembre del 2012, San Francisco de Campeche, Campeche, MéxicoPeer Reviewe

Homothallic auxosporulation in Pseudo-nitzschia brasiliana (Bacillariophyta)

8 pages, 5 figures, 3 tablesMost pennate diatoms are allogamous, and various types of mating systems have been described. In Pseudo-nitzschia, reproductive stages have been identified in some species, and it is generally accepted that the genus is mainly heterothallic. Here we report homothallic auxosporulation of Pseudo-nitzschia brasiliana Lundholm, Hasle et G. A. Fryxell. To our knowledge, this is the first verified description of homothallic sexual reproduction in the genus. Auxospore formation was observed in all 16 subclones derived from three initial clonal cultures of P. brasiliana. Pairing was followed by production of two gametes per gametangium, which fused to give two zygotes. Each zygote (early auxospore) was initially spherical and adhered to one girdle band of the parental frustule. The two auxospores tended to expand parallel to each other and perpendicular to the parental frustule. Elongation was synchronous, slightly asynchronous, or totally asynchronous. The entire process of sexual reproduction, from gamete formation to the appearance of the initial vegetative cells, took 2–4 d. The occurrence of sex in a homothallic species seems an advantageous life strategy for this species in that any encounter between cells of the right size class is potentially sexualThis study was supported by the EC funded Research Project SEED (Life cycle transformations among HAB species, and the environmental and physiological factors that regulate them), GOCE-CT-2005-003875, and the CRA (Centre de Referencia en Aquicultura, CIRIT-Generalitat de Catalunya, Spain). E. Garcés work was supported by a Ramon y Cajal contract of the Spanish Ministry of Education and Science. S. Quijanós work was supported by a PROMEP grant (Mexico), Colima UniversityPeer reviewe