ABSTRACT Microalgae can accumulate lipids during the stationary growth phase, but little information is available about fatty acid profile changes during this phase to determine the best harvesting time in respect to lipid content. In this study, Dunaliella sp. was cultured in F/2 medium at three different photon flux densities (380, 226 and 8.2 μmol photon m-2 s-1) and three different glycerol concentrations (0, 10 and 20 g L-1). Samples were taken during the stationary phase to assess lipid content and fatty acid profile variations. Microalgal biomass production was higher at 380 and 226 μmol photon m-2 s-1 than at 8.2 μmol photon m-2 s-1 in accord to light limitation. The maximum lipid content (345.78 mg g-1) was achieved at 8.2 μmol photon m-2 s-1 and 20 g L-1 glycerol at day 12, similar to that achieved at day 9 (334.16 mg g-1). The maximum polyunsaturated fatty acid amount (65.30 μg mg-1) was achieved at day 7 of culture without glycerol addition, decreasing in proportion over time. So, the best conditions and harvesting time in respect to fatty acid quality would be at 380 μmol photon m-2 s-1 without glycerol addition and after 7 days of culture.

ABSTRACT Páramo ecosystems are of great importance because they are considered hotspots within the Tropical Andes. They are also very important for their role as producers and regulators of water processes in the Neotropic. However, the human occupation of the Colombian Páramos has generated conflict between environmental benefits and productive land uses, specifically the potato cultivation and livestock. To assess possible changes associated with potato cultivation (Solanum tuberosum L.) and livestock on the microbial communities of Páramo soils, the objective of this research was to evaluate the possible effects of potato cultivation and livestock farming on the soil microorganisms associated with different functional groups (nitrogen fixers, phosphate solubilizers and cellulolytic) in the Páramo of Nevados National Natural Park (Nevados NNP), Colombia. Samples were collected from soils under potato cultivation, livestock, and Páramo conservation areas over two climatic seasons (rainy and dry) in three farms at different elevations (3769, 3590, and 3432 m a.s.l.). The microorganisms were isolated using selective culture media for each functional group and identified using molecular markers; microbial diversity was analyzed using multivariate statistical tools. Changes were dependent on land use, elevation, and climate and were statistically significant in the rainy season on all three farms and one of the farms during the dry season. Similarly, the results indicated that climate has a greater impact on the evaluated microbial communities than land use does; the changes were significantly different between the soil under potato cultivation and in conserved Páramo sites at most of the evaluated locations and between soil subjected to livestock farming and Páramo in certain locations. However, the differences between potato cultivation and livestock farming were smaller. This study showed for the first time that the microbial structure (abundance and composition) of microorganism functional groups was different as a result of potato cultivation and livestock farming on Páramo soils, although these changes were dependent on farm elevation and climate.

Para la estimación de la estructura de tamaños en cangrejos terrestres comerciales y la obtención de información relevante para su manejo, es necesario utilizar métodos rápidos, confiables y no destructivos. Cardisoma guanhumi y Ucides cordatus son dos cangrejos terrestres que son explotados comercialmente en el Caribe y en Brasil. El propósito de este trabajo es suministrar métodos indirectos para la estimación del tamaño del caparazón de los cangrejos y por consiguiente, de la estructura de tallas. Los muestreos se llevaron a cabo en Carenero (C. guanhumi) y en Cumaná (U. cordatus) (Venezuela). Se utilizaron tres métodos para estimar el diámetro de sus madrigueras: Vernier, compás y fotografía. Estos se correlacionaron con el tamaño real del cangrejo. Se aplicó el análisis de regresión Ordinary Least Squares Model II y la capacidad de predicción se probó utilizando el modelo II Mayor Axis para las regresiones. Cardisoma guanhumi mostró una fuerte dispersión de sus datos en los métodos de Vernier y fotografía. Menos dispersión se obtuvo con el método del compás y fue el más preciso (r²= 0.61). Para U. cordatus las medidas con Vernier fueron la más adecuadas (r²= 0.71). Sin embargo los tres métodos fueron confiables. Los diferentes métodos mostraron ventajas y desventajas y dependerá del que aplique los métodos, decidir cuál será el más adecuado para sus propósitos

Quick, reliable and non destructive methods are necessary to estimate size structure on commercial land crabs, in order to acquire relevant information concerning the health of their populations. Cardisoma guanhumi and Ucides cordatus are two land crabs that are exploited at a high scale and also in an artisan way in the Caribbean area and in the coasts of Brazil, which populations are endangered due to uncontrolled exploitation. The purpose of this work is to provide various methods to estimate indirectly crab body size. Sampling was carried out in Carenero (C. guanhumi) and Cumaná (U. cordatus) (Venezuela). For each species, three methods were used to measure burrow diameter (Vernier, internal spring caliper and photograph), and these were correlated with real body size of the crabs. Model II linear regression analyzes, i.e. Ordinary Least Squares and Mayor Axis, were used to build and test the performance of forecasting models. Cardisoma guanhumi showed a high bivariate data dispersion using Vernier and photo measuring methods, increasing these towards larger animals. Less dispersion was achieved with the spring caliper method; this resulted in the most accurate measurements of indirectly estimated body size in C. guanhumi (r²= 0.61), whereas Vernier measurements were the least precise. On the other hand, all three methods gave reliable estimates for U. cordatus, being the Vernier method the most accurate (r²= 0.71). However, in both species, all forecasting equations overestimated the size of smaller crabs (those below the mean) but underestimated the size of larger crabs. Nevertheless, all three methods were statistically significant for each of the species, and looking at the above mentioned underand overestimations, they can serve as reliable and fast non-destructive tools to be used by resource managers and field biologists to acquire size structure information concerning these two species. Vernier and internal spring caliper methods are recommended for relative small sampling areas, while photo method is suggested to be used in very extensive sampling regions

Apesar das ascídias formarem uma parte conspícua das comunidades incrustantes no Caribe, nenhum inventário especializado foi realizado na Venezuela, com exceção de uma lista de 15 espécies registradas na Ilha Margarita (1984). Aqui apresentamos os resultados de um workshop de taxonomia realizado na Universidad de Oriente, Boca del Rio, Margarita Island em 20-25 de abril de 2009, como parte do programa NaGISA-Caribbean Sea program. O Parque Nacional La Restinga foi estudado e encontradas 29 espécies pertencendo a 19 gêneros e 10 famílias. As espécies coloniais mais abundantes foram Clavelina oblonga, Aplidium accarense, Polyclinum constellatum, Distaplia bermudensis, Symplegma rubra, S. brakenhielmi, Botrylloides nigrum e Ecteinascidia turbinata. Entre as espécies solitárias, Phallusia nigra, Ascidia curvata, Microcosmus exasperatus, Styela canopus, Styela sp.1 e Styela sp. 2 foram as mais abundantes. A diversidade de ascídias nesta laguna é uma das maiores neste tipo de habitat no Caribe e sete espécies representam novos registros para a Venezuela (Ascidia curvata, Ecteinascidia styeloides, Aplidium accarense, Distaplia stylifera, Trididemnum orbiculatum, Symplegma rubra, e S. brakenhielmi). Uma questão de preocupação para a conservação do Parque Nacional La Restinga é a presença de possíveis espécies exóticas, portanto algumas medidas de manejo são sugeridas.

Although ascidians form a conspicuous part of sessile assemblages in the Caribbean, no specialized inventories have been developed in Venezuela, except for a list of 15 species reported from Margarita Island (1984). Here we present the results of a taxonomic workshop held in the Universidad de Oriente, Boca del Rio, Margarita Island during April 20-25 of 2009, sponsored by the NaGISA-Caribbean Sea program. La Restinga National park was surveyed and we found 29 species belonging to 19 genera and 10 families. The most abundant colonial species were Clavelina oblonga, Aplidium accarense, Polyclinum constellatum, Distaplia bermudensis, Symplegma rubra, S. brakenhielmi, Botrylloides nigrum and Ecteinascidia turbinata. Among the solitary ascidians Phallusia nigra, Ascidia curvata, Microcosmus exasperatus, Styela canopus, Styela sp.1 and Styela sp. 2 were the most abundant. The ascidian diversity in this lagoon is one of the highest for similar habitats in the Caribbean and seven species are new registers for Venezuela (Ascidia curvata, Ecteinascidia styeloides, Aplidium accarense, Distaplia stylifera, Trididemnum orbiculatum, Symplegma rubra, and S. brakenhielmi). One point of concern for the conservation of la Restinga National Park is the presence of possible introduced species, and some management procedures are suggested.

La utilidad del ADN mitocondrial (ADNmt) para determinar afinidad genética entre grupos indígenas contemporáneos e inferir sobre migraciones, ha sido demostrada; pero la imposibilidad de estudiar grupos prehispánicos extintos, limita las inferencias sobre migraciones en esa época. El mestizaje en poblaciones neoamericanas ha sido caracterizado por uniones entre hombres europeos y mujeres indígenas, permitiendo detectar en la población contemporánea haplogrupos mitocondriales amerindios que informan sobre poblaciones extintas. Para conocer los linajes femeninos en el occidente de Venezuela, se estudiaron los haplogrupos del ADNmt a partir de RFLP, en una muestra de 193 individuos con antepasados procedentes del occidente de Venezuela, 81 del Estado Lara (Barquisimeto) y 112 de tres pueblos del Estado Falcón (Macu-quita=25, Macanillas=29 y Churuguara=58). Se comparó la distribución de haplogrupos entre las poblaciones y se estimó el mestizaje por línea femenina en ellas. Se comparó la distribución de cuatro haplogrupos indígenas con otras regiones de América. Se observa que en las cuatro poblaciones predominan haplogrupos amerindios, seguidos de los africanos. Al comparar la fracción indígena con el resto de América encontramos que Macanillas, Lara y Churuguara se asemejan a grupos de Amazonas y Suramérica, mientras que Macuquita a Aruba. Esto sugiere una diversidad genética importante en esa zona como probable ruta de paso hacia el sur y el Caribe; además refleja vínculos genéticos importantes entre grupos prehispánicos de Aruba y los de la Península de Paraguaná. Evidencias arqueológicas soportan estos postulados. Se recomienda aumentar la muestra y realizar análisis de secuencias para un nivel mayor de precisión.

Mitocondrial DNA (mtDNA) has been widely used to study genetic relationships between contemporary Amerindian groups and to infer ancestral migration movements; however inferences about migration routes of prehispanic extinct groups are difficult. Admixture of Neoamerican groups has been characterized by unions between European males and Amerindian females. This allows the identification in present populations of Amerindian mitocondrial haplogroups which give information on ancestral groups. In order to investigate female lineages present in western Venezuela, RFLP haplogroups from mtDNA were obtained from 193 individuals with grandparents from this region, 81 from the State of Lara (Barquisimeto) and 112 from 3 towns of the State of Falcon (Macuquita=25; Macanilla=29 and Churuguara=58). Comparison of haplogroup distributions between groups was performed, and admixture estimates based on female lineages were obtained. The distribution of four Amerindian haplogroups was compared with those of other populations from the American Continent. In our four samples Amerindian haplogroups predominate, followed by those of African origin. In the comparison of the mtDNA Amerindian fraction with other populations we find that Macanillas, Lara and Churuguara are similar to South American and Amazonian groups whilst Macuquita is similar to groups from Aruba. Our findings suggest an important genetic diversity in this region, explained by migration routes to and from the south and the Caribean. They also suggest genetic relationship between prehispanic groups from Aruba and those from the Paraguaná peninsula, which have been inferred by archeological evidences. An increase in sample size and analysis of sequences for more precision is recommended.