Survey of food network in Ovan Lake

Lake Ovan with about 9 hectares is regarded a semi-shallow lake with an average depth 5.2 meter. It is situated in Ghazvin Province, with a 1910 m high in mountainous regime. A monthly sampling was done at 3 stations studying the physicochemical and biological parameters in water and sediment at the Lake for a year. The temperature annual was measured 12.3°C and other parameters are pH as 8.8, oxygen 10, with total mean phosphate and nitrate as 0.14 & 0.8 mg/lit respectively. The chl.a mean was also measured 1.94 mg/lit. The ratio of N to P was calculated as 1:59, indicating a limiting factor for growth. Considering the trophic statues of the lake taking into account as above parameters, it is a mesotrophic lake with medium trophy. Altogether, 53 phytoplankton species were identified mostly diatoms, green algae and cyanobacteria. Although, 14 zooplankton species were identified with daphnia dominating the group. Macrobenthoses were also surveyed and 11 families were identified comprising mainly by Annelids, Gastropod, Bivalves and Insect Larvae. Other organisms were 2 dominate water plant including Phragmites australis covering at the edge of the lake and potamogeton sp in the inner parts, and also 2 fish species, common carp and Pike Perch. The diversity Shannon—Wiener index was calculated for main taxa groups with all figures lower than 3. Regarding the fish potential production of the lake based on Bramic & Lemke and morphoedophic index, it was calculated to be 20.4 kg/ha fish and a total of about 150 kg for the entire lake.

Site n°5. The Pertuis Breton (Bay of Biscay) France

1.This report presents the results of a field study conducted in the ECASA test site nOS in the Pertuis Breton, France. The site is located on the Atlantic West coasts. It is open to the bay of Biscay, but is slightly protected against westerly winds. The bay has been exploited by intertidal mussels culture for centuries. 2. Within the bay, mussels (Mytilus edulis) are cultivated either by the traditional pole technique, around the bay or on longlines in the centre of the bay. The area occupied by these longline s represents 250 ha, and the resulting annual production is 1 000 tonnes of mussels. The average depth at mid tide is of 13.8 m. The sediment is sandy, with a small fraction of mud. 3. The site is subject to several regular monitoring through the local implementation of national networks aiming at protecting the environment and marine resources, on pollutants (RNO), microbiological quality of the waters (REMI), phytoplanktonic toxic species (REPHY) and growth and mortality of molluscs (REMORA). Benthic macrofauna was studied in 1976. 4. Five sampling sations were chosen along a line, starting under the longlines, and at distances of 50, 100, 200, and 400 metres from the area cultivated. A reference station was chosen in a different direction at 2300 metres of the cultivated area. Sampling methods are described in the text. _Sediments were sampled for different analyses: grain size, content in organic matter, total organic carbon and nitrogen, and phytic pigments (chlorophyll a and phaeopigments). Redox were measured in cores. The macrofauna living into the sediment was also sampled. The water column was sampled for physical (temperature, transparency) and chemical parametres, including oxygen content, salinity, organic matter, dissolved nitrogen forms, phosphates and silicates. Results from benthic macrofauna surveys indicate that there were no significant differences between the different stations and the reference station, all being classified as slightly disturbed. The bay is submitted to freshwater runoffs from two adjacent rivers. 7. The sediment is slightly modified by the culture of bivalves. Total organic carbon, total nitrogen, Eh values and pheopigments were significantly higher under the trestles than in any other stations. Other stations often did not differ from the reference station. 8. The effects of shellfish culture on the water column were. However, it was observed a small decrease of the food available to the molluscs near the rearing 9. The DEB model was able to describe and predict adequately the growth of oysters, both in the Baie des Veys and in the Loch Creran. The parametres for its use in other environment are given, but a tuning of one parametre should be performed with the help of authors. 10. Among the indicators and models for use in are as of intertidal bivalve culture, it is recommended to use the sediment quality index, TOC (Total Organic Carbon), redox and pheopigments, in surficial sediment, AMBI for the macrofauna, chlorophyll a contents and nitrogen forms in the water column, and models describing the carrying capacity, filtration rate of molluscs, and a DEB model to predict the growth of molluscs.

A Matemática da Natureza : Os padrões decorativos das conchas marinhas

(...) Os padrões decorativos que revestem as conchas de moluscos marinhos tropicais constituem um claro convite a uma análise mais profunda. Estes padrões são registos do crescimento das próprias conchas, seguindo leis como as da formação das dunas nos desertos ou da propagação de uma epidemia de gripe. (...) A diversidade dos padrões, que podem diferir em detalhes, mesmo entre conchas da mesma espécie, sugere um mecanismo morfogenético geral o suficiente para abranger variações espécime-a-espécime e espécie-a-espécie. Este mecanismo de reação-difusão é expresso, em termos matemáticos, por sistemas de equações diferenciais de derivadas parciais. (...)

Sedimenttexturen der Sohlbankfläche im Naturdenkmal "Saurierfährten Münchehagen" (Berrias), Rehburger Berge : Rippelmarken und Ichnofossilien als Grundlage einer Deutung des Ablagerungsraumes

Die Gesteine des bearbeiteten Aufschlusses, dem Naturdenkmal "Saurierfährten Münchehagen" bei Münchehagen (Rehburger Berge), liegen stratigraphisch in der Bückeberg-Formation des Berrias (Wealden). Aufgeschlossen ist der Hauptsandstein (Wealden 3) . Es werden die Sedimenttexturen der Sohlbankfläche des ehemaligen Steinbruchs analysiert und interpretiert. Vorherrschende Schichtungstypen sind Wellenrippelschichtung und Flaserschichtung. Die Sedimente sind stark bioturbat. Auf mehreren freiliegenden Flächenniveaus der Sohlbank sind Rip- pelmarken zu beobachten, die systematisch vermessen wurden. Danach handelt es sich uro Wellenrippeln und untergeordnet um strömungsüberformte Wellenrippeln durch ablaufendes Wasser. Zahlreiche Merkmale zeigen wiederholtes Auftauchen und Trok- kenfallen an. Tonlagen kennzeichnen zeitweilige Stillwasserbedingungen. Ein ehemals verzweigtes Rinnensystem ist in Relikten erhalten und beweist ebenfalls einen wechselnden Wasserstand (ablaufendes Wasser). Sporadisch kam es im Zuge hochenergetischer Ereignisse zu einem schichtflutartigen Abfließen des Wassers. Eine reiche Ichnofauna ist zu beobachten. Wenige Spurentypen sind vorhanden, die Spurendichte ist jedoch sehr hoch. Es dominieren horizontale oder wenig geneigte Gestaltungswühlgefüge, vertikale Bauten kommen nur untergeordnet vor. Als häufigste Spurentypen treten Thalassinoides, Muensteria, Plano- lites und Pelecypodichnus auf. Die Größe der Ichnofossilien ist meist gering. Die Spuren bilden eine Ichnocoenose aus Ichnofossilien der Cruziana- und untergeordnet der Skolithos- Fazies. Bivalven belegen Brackwasser-Verhältnisse. Dies alles sind Merkmale eines lagunären Ablagerungsraumes, gelegen am Rand eines gezeitenarmen bzw. -losen Nebenmeeres (Niedersächsisches Becken) im Übergang von der fluviatilen in die litorale Fazies im rückwärtigen Bereich eines Barrierensystems. Wahrscheinlich spielte Wind eine entscheidende Rolle als Ursache für Wasserspiegelschwankungen. Die maximale Wassertiefe bei auflandigem Sturm hat vermutlich nicht mehr als 3 - 4 m betragen. Sonst war sie wahrscheinlich deutlich geringer und ermöglichte Dinosauriern ein Durchwaten des Gewässers, wie Fährten auf der Sohlfläche beweisen.

Distribución y abundancia de Opistobranchios (Mollusca) en el área natural protegida complejo Los Cóbanos, Sonsonate, El Salvador

Se estudió la distribución y abundancia de la fauna opistobranchia en cuatro estaciones de monitoreo ubicadas en cuatro playas que forman parte del Área Natural Protegida Complejo Los Cóbanos, siendo estas: playa Los Cóbanos, playa El Faro, playa La Privada y playa de Decameron (Salinitas); en el municipio de Acajutla, departamento de Sonsonate, El Salvador; durante los meses de diciembre de 2014, a abril de 2015. Se utilizó la metodología de transectos lineales de 300m perpendiculares a la costa, en la zona intermareal y cuadrantes de 10m2 aplicando conteos visuales con buceo libre. Se contabilizaron un total de 9 especies, pertenecientes a los órdenes anaspidea, sacoglossa, nudibranchia, cephalaspidea; con un total de 2728 individuos, de estos la especie más abundante fue Elysia diomedea, con 1417 individuos; seguida de Stilocheilus striatus con 1171 individuos. La playa con mayor riqueza de especies fue El Faro y con menor Los Cóbanos; se presentó una mayor abundancia en el mes de abril, y menor abundancia en el mes de febrero. Respecto a la distribución, el mayor número de individuos de Elysia diomedea fueron encontrados a los 200m, Estilocheilus striatus hasta los 200m presenta mayor número de individuos y Dolabrifera dolabrifera presenta mayor número de individuos hasta los 100m, siendo su amplitud de distribución corta; el resto de especies no se puede concluir que presenten una afinidad específica hacia una distancia particular. La similitud entre las especies encontradas fue variada: en el caso de Glossodorys sedna, presentó una similitud del 0% respeto al resto de especies, la mayor similitud corresponde a Elysia diomedea y Stilocheilus striatus, con el 41% de similitud. Respecto a la diversidad, la playa que presentó un mayor valor de diversidad fue La Privada, siendo la menos diversa Decameron. Los datos obtenidos en la presente investigación pueden ser empleados en la planificación de actividades de conservación y manejo sostenible del ecosistema.

Dieta del “curil” Anadara tuberculosa (Sowerby, 1833) a partir del análisis de contenido estomacal e intestinal, en Bahía de Jiquilisco, Departamento de Usulután, El Salvador

En la costa de El Salvador, el “curil” (Anadara tuberculosa), constituyen una fuente importante de alimento, empleo y beneficios económicos para las personas que habitan en las cercanías de zonas costeras y estuarinas del país. Aunque ésta especie es reproducida artificialmente en el laboratorio de la Estación Acuícola de Producción de Moluscos de Puerto el Triunfo, Usulután, no existe información específica acerca de sus hábitos alimenticios en su hábitat natural para la región centroamericana. Por lo cual, el presente trabajo tuvo como objetivo determinar la composición específica de su dieta, a través del contenido estomacal e intestinal durante los meses de septiembre 2013 a enero 2014 en cuatro sitios de la Bahía de Jiquilisco, El Chile (EC), EL Jobal (EJ), Boca Los Lagartos (BL) e Isla Magueyal (IM). Se analizaron un total de 540 tractos digestivos de Anadara tuberculosa, obteniendo un total de 30,328 ítems alimenticios, en su mayoría correspondientes a 37 especies de diatomeas (95,91%), principalmente por los géneros Thalassiosira plicata (12,78%), Diploneis smithii (9,21%), Diploneis gruendleri (7,59%), Thalassiosira sp. (5,0%), Thalassionema nitzchioides (4,91%). Además, se aplicaron los índices de Levins (Bi=0,42) y Shannon-Wiener (H’=3,24), para amplitud y diversidad de dieta, respectivamente, indicando que esta especie se tipifica como especialista, debido a que presenta un espectro trófico diverso, dominado por pocas especies. Así mismo, se realizó un traslape de dieta de Morisita-Horn, en cuanto a rangos de tallas establecidos (menores de 4 cm, 4-5 cm y mayores de 5 cm), encontrando valores de Cλ=0,50 a 0,90, evidenciando que existe un traslape medio-alto en las especies filtradas por las diferentes tallas; así como también, para los sitios de muestreo se estimaron los índices de similitudes de Jaccard (Ij= 0,63-0,82) y Sorensen (Is= 0,72-0,90) indicando que no existen diferencias significativas en cuanto a los ítems alimenticios encontrados en los tractos digestivos de A. tuberculosa para la Bahía de Jiquilisco.

Estimation of mercury background values in sediment and biota of the Bijagós archipelago, Guinea-Bissau

This work evaluates the mercury (Hg) contamination status (sediments and biota) of the Bijagós archipelago, off the coast of Guinea-Bissau. Sediments exhibited very low concentrations (<1-12ngg(-1)), pointing to negligible sources of anthropogenic Hg in the region. Nevertheless, Hg is well correlated to the fine fraction, aluminium, and loss on ignition, indicating the effect of grain size and organic matter content on the presence of Hg in sediments. Mercury in the bivalves Tagelus adansoni and Senilia senilis did not vary considerably among sites, ranging within narrow intervals (0.09-0.12 and 0.12-0.14μgg(-1) (dry weight), respectively). Divergent substrate preferences/feeding tactics may justify slight differences between species. The value 11ngg(-1) is proposed as the sediment background concentration for this West-African coastal region, and concentrations within the interval 8-10ngg(-1) (wet weight) may be considered as reference range for S. senilis and T. adansoni in future monitoring studies.

Ingestion of a bacterivorous ciliate by the oyster Crassostrea gigas: Protozoa as a trophic link between picoplankton and benthic suspension-feeders

The linked concepts of 'microbial loop' and 'protozoan trophic link' have been very well documented in filter-feeding microzooplankton such as copepods, but have not been applied to energy transfer to benthic suspension-feeding macrofauna, with the exception of the recent demonstration of heterotrophic flagellate assimilation by mussels. The oyster Crassostrea gigas obtains energy resources by filtering microalgae (similar to 5 to 100 mu m). However, in turbid estuaries, light-limited phytoplanktonic production cannot entirely account for oyster energy requirements. Conversely, picoplankters (<2 mu m), which are main effecters of coastal energy flow and matter cycling, are not efficiently retained by oyster filtration. Ciliate protozoal as both micro-sized cells (similar to 5 to 100 run) and bacteria grazers, may represent a major intermediary in trophic transfer between picoplankton and metazoa. The ciliate Uronema was intensely cultured and labelled, using the cyanobacteria Synechococcus as an auto-fluorescent biomarker. The labelled ciliates were offered as potential prey to oysters. We report here the first experimental evidence of a significant retention and ingestion of ciliates by oysters, supporting the role of protozoa as a realistic trophic link between picoplankters and filter-feeding bivalves and thus enhancing their potential importance in estuarine microbial food webs.

Evaluación de carga microbiana termotolerantes (Escherichia coli) post tratamiento de inmersión del “Curil” (Anadara tuberculosa), en agua sometida a radiación ultravioleta

Los moluscos bivalvos se alimentan por filtración logrando ingerir partículas en suspensión que pueden contener microorganismos patógenos a un nivel muy superior al de su entorno acuático, por lo tanto los riesgos de enfermedades gastrointestinales para humanos se asocian al consumo de moluscos crudos. Muchas de estas enfermedades transmitidas por moluscos se deben a bacterias entéricas asociadas con contaminación fecal. Para controlar las enfermedades transmitidas por moluscos, se ha ideado la limpieza de moluscos de los contaminantes presentes en su tejido a través de la depuración (un sistema controlado), este es un proceso que consiste en mantener a los bivalvos en tanques con agua de mar libre de contaminantes microbiológicos, en condiciones que permitan maximizar la actividad natural de filtración y expulsar así el contenido intestinal donde están presentes las bacterias nocivas para el consumo humano. La presente investigación consistió en evaluar la depuración a la que se sometió el “curil” (A. tuberculosa) para reducir la carga microbiana de Escherichia coli y Coliformes, donde los “curiles” se introdujeron en agua radiada con luz ultravioleta, bajo condiciones de temperatura, salinidad y pH, por periodos de tiempo de 24, 48, y 72 horas. Los ejemplares analizados fueron 51muestras, 24 de ellos se extrajeron de los sitios de cultivo Las Flores y El Jobal de la Bahía de Jiquilisco, del Departamento de Usulután y el resto fueron recolectados en un establecimiento comercial de mariscos de la misma zona para determinar la capacidad máxima del sistema depurador, también se analizó 21 muestras del agua radiada con luz UV para demostrar la efectividad del sistema depurador. Las muestras colectadas de tejido de “curil” y agua de mar fueron trasladadas al Laboratorio del Centro de Investigación y Desarrollo en Salud (CENSALUD) de la Universidad de El Salvador, para la realización del análisis microbiológico mediante la técnica de placa vertida por medio del recuento de Unidades Formadoras de Colonias (UFC/g) (Cuantificación de Coliformes) y Número Más Probable (NMP/ml) (Comprobación de presencia de E. coli), ambas técnicas recomendadas por la Administración de Alimentos y Medicina de los Estados Unidos de América (FDA, por sus siglas en inglés)

Seaweed Aquaculture and Marine Biotechnology

Macroscopic marine algae, typically known as macroalgae or seaweeds, form an important living resource of the oceans, as primary producers. People have collected seaweeds for food, both for humans and animals for millennia. They also have been a source of nutrient rich fertilizers, as well as a source of gelling agents known as phycocolloids. More recently macroalgae are playing significant roles in medicine and biotechnology. Although Biotechnology and in particular marine biotechnology may have different meanings for different people, under the present context we will consider a broader definition. Marine biotechnology consists on the use of biological knowledge and/or the application of biological techniques on marine organisms, for the development of products in some way beneficial for humans. Seaweed aquaculture is, therefore a biotechnology activity. It is also one that can allow for further development of the industry. Today, seaweed cultivation techniques are standardized, routine and economical. Several factors, including understanding the environmental regulation of life histories and asexual propagation of thalli, are responsible for the success of large-scale seaweed cultivation. Presently, seaweed aquaculture represents approximately 23% of the world’s aquaculture production, including fish, crustaceans and other animals. A promising approach for the development of seaweed aquaculture, and aquaculture in general, is the integrated multi-trophic aquaculture (IMTA). In these systems, fed-aquaculture is combined with extractive organisms like bivalves and/or algae. The constraints and advantages of IMTA will be discussed. In particular, land based IMTA systems allow for much greater environmental and input controls. Traceability, security of supply, high-quality standards and safety should be the future of seaweed aquaculture and contribute for the development of marine biotechnology.

Contrat de Plan État-Région Bretagne. Relance de l'huître plate. Rapport d'avancement des travaux 1988.

Un contrat de Plan État-Région Bretagne a été signé en 1983 pour financer des recherches sur la période 1984-1988 dans le but de permettre la relance de l'élevage de l'huître plate, à la suite de la deuxième épizootie due à un protozaire, Bonamia ostreae. Ce rapport présente les travaux réalisés et les résultats acquis durant l'année 1988, dans les domaines de la pathologie (étude de la maladie et des mécanismes de défense des mollusques) de la génétique (recherche de souches résistantes), de l'épidémiologie descriptive et de la zootechnie.

Processo biotecnológico voltado a produção de estoques poliploides do camarão-branco litopenaeus vannamei (decapoda, penaeidae)

without practical results so far. Protocols used in biotechnological cultured aquatic organisms aimed at increasing growth rates and disease resistance, have been studied and perfected. Among the available techniques, the application of chromosomal manipulation, although still nascent, is presented as a tool aimed at mitigating ecological and economical issues in shrimp farming. The polyploidization artificial method already employed in fish and shellfish, has been widely researched for use in farmed shrimp. Some limitations of this method of expansion in shrimp refer to a better knowledge of cytogenetic aspects, the level of sexual dimorphism and performance in growing conditions. To contribute on some of these issues, the present study aimed to characterize cytogenetic species Litopenaeus vannamei (Decapoda) and Artemia franciscana (Anostraca), analyze the effectiveness of methods for detection of ploidy, through the use of flow cytometry in processes of induction polyploidy cold thermal shock at different stages of development of newly fertilized eggs. Additionally, aimed also the qualitative and quantitative comparison of larval development between diploid and polyploid organisms, besides the identification of sexual dimorphism in L. vannamei, through geometric morphometrics. The results provide information relevant to the improvement and widespread use of biotechnological methods applied toward national productivity in shrimp farming

Nuevos datos sobre la fauna del Cámbrico Inferior (Marianense) de Llerena (Badajoz)

Se dan nuevos datos sobre los invertebrados fósiles encontrados en el río Viar (Badajoz) de edad Cámbrico Inferior (Mananense), dándose una relación de fauna que consiste en: Trilobites (Serrodiscus, Termierella, Aldonaia, Saukianda e Hicksia), Celentéreos (Scenella), Braquiópodos (inarticulados indet.) y Moluscos (Hyolitha).

Faisabilité biologique de la production de larves d'huîtres creuses Crassostrea gigas à partir d'eau de mer du site de Leucate. Convention de recherche Ifremer/Région Languedoc-Roussillon - Rapport final.

Afin de vérifier sur un site régional la présence d'une qualité d'eau de mer permettant la réalisation d'élevages larvaires d'huîtres creuses Crassostrea gigas (et/ou d'huîtres plates Ostrea edulis) sur une base régulière tout au long de l'année, une série d'élevages comparatifs a été réalisée à la Station IFREMER de Palavas, de mars 1995 à septembre 1995. Le matériel biologique nécessaire à cette comparaison est constitué de larves d'huîtres creuses Crassostrea gigas et en algues unicellulaires provenant de l'éc1oserie commerciale de la SATMAR. Les résultats obtenus démontrent la capacité de l'eau de mer du site étudié sur Leucate à supporter la production de larves d'huîtres creuses compétentes à se métamorphoser et à se fixer. Cette étude s'inscrit dans la démarche de la Région Languedoc-Roussillon et du CEPRALMAR visant à favoriser l'implantation d'une écloserie de production de Mollusques Bivalves sur le littoral méditerranéen.

Uso do bivalve límnico Anodontites tenebricosus (LEA, 1834) no biomonitoramento de metais do Rio Ribeira de Iguape

This study investigated the contamination of the Ribeira de Iguape River - RIR by Cd, Zn, Cr and Pb, using the bivalve Anodontites tenebricosus as a biomonitor. Metal concentrations in tissue samples were measured by HR-ICPMS. Bivalve tissues exhibited mean levels of 1.00 µg/g Cd; 152.89 µg/g Zn; 14.79 µg/g Cr and 4.40 µg/g Pb. Lead concentrations were comparable to those reported for moderately contaminated sites. The results showed that Pb is bioavailable to the bivalves, exhibiting high concentrations and exceeding both natural and reference values for human consumption. The freshwater bivalve Anodontites tenebricosus is a suitable biomonitor of contamination by metals.