Structure of the aquatic Diptera community in the upper basins of the Fucha and Bogotá rivers / Estructura de la comunidad de dípteros acuáticos en tramos de los cursos altos de los ríos fucha y bogotá

RESUMEN Los macroinvertebrados acuáticos son bien conocidos como bioindicadores de la calidad del agua. En Colombia, los estudios sobre este tema se han hecho principalmente a nivel taxonómico de familia. En este trabajo se analizan las respuestas en abundancia, riqueza y diversidad de los dípteros identificados a nivel de género en ríos altoandinos (río Bogotá y río Fucha), en épocas de aguas bajas y aguas altas. Los especímenes se recolectaron con tres métodos: red Surber, red de mano y lavado de rocas. La temperatura promedio fue de 12,9 °C y la saturación de oxígeno estuvo cerca del 100 % o más, con excepción del tramo bajo del río Bogotá antes de Villapinzón. Se colectaron 13 690 dípteros pertenecientes a diez familias y 40 géneros. La riqueza taxonómica fue alta, con una mayor variación en los tramos bajos de las dos corrientes. Las subfamilias de Chironomidae fueron las más abundantes. El análisis de correspondencia canónica (ACC) mostró que los Orthocladiinae se asociaron con la conductividad; el género Gigantodax (Simuliidae) no mostró una relación clara con ninguna variable; por el contrario, el género Simulium se vinculó con el caudal. En términos generales, la asociación entre taxones y variables ambientales fue más clara para los géneros que para las familias, pero no fue suficientemente robusta. Se sugiere que para encontrar un mayor grado de asociación biota-ambiente, es necesario realizar los análisis a nivel de especie, considerando las variaciones locales y temporales.

ABSTRACT Aquatic macroinvertebrates are recognized as bioindicators of water quality. In Colombia, the studies have mainly been addressed by the family taxonomic level. This work analyzes the responses in abundance, richness, and diversity of the Diptera at the genus level in high Andean rivers (Bogotá River and Fucha River), in periods of low and high waters. The specimens were collected with three methods: Surber net, hand net, and rock washing. The average temperature was 12.9 °C and oxygen saturation was close to 100 % or more, except for the lower section of the Bogotá River, before the Villapinzón town. 13 690 Diptera were collected from ten families and 40 genera. Taxonomic richness was high with the greatest variation in the lower sections of the two streams. The Chironomidae subfamilies were the most abundant. Canonical correspondence analysis (CCA) showed that Orthocladiinae were associated with water conductivity; the Gigantodax genus (Simuliidae) did not show a clear relationship with any variable; conversely, the genus Simulium was linked to the caudal. In general terms, the association between taxa and environmental variables was clearer for genera than for families, but it was not robust enough. It is suggested that to find a higher degree of biota-environment association, it is necessary to carry out analyzes at the species level, considering local and temporal variations.

Ecología funcional de las algas perifíticas en el Chocó colombiano: limitación de recursos, competencia y variables ambientales / Functional ecology of periphytic algae in the Colombian Chocó: resource limitations, competition, and environmental variables

Introducción: El conocimiento de las comunidades perifíticas es importante, dada su participación en la producción primaria de los ambientes fluviales; además, el perifiton es una valiosa comunidad bioindicadora. No obstante, hasta la fecha es poco lo que se conoce sobre la ecología funcional de esta comunidad en los ríos colombianos. Objetivo: En este trabajo se buscó caracterizar algunos aspectos funcionales de la comunidad de ficoperifiton de cuatro sistemas lóticos de la Reserva Natural La Planada, ubicada en el departamento de Nariño, Colombia. Métodos: Durante mayo de 2019, en cada río se establecieron entre uno y tres sitios de muestreo, en los cuales se midieron las características hidrológicas y fisicoquímicas y se determinó la composición taxonómica y algunos rasgos funcionales de las comunidades de algas perifíticas. Se calcularon la media ponderada comunitaria (MPC) y la varianza ponderada comunitaria (VPC) de estos rasgos y se exploró su relación con las variables abióticas mediante regresiones, correlaciones y análisis de correspondencia canónica (ACC). Resultados: Se registraron 59 géneros de algas, de los cuales a 47 se les midieron los rasgos funcionales. La MPC del rasgo exoesqueleto silíceo fue estadísticamente mayor en la quebrada El Tejón. La MPC y la VPC de los demás rasgos no varió entre ríos, pero en algunos de ellos la presencia de mucílago y la organización en filamentos tendió a ser mayor. La amplia fluctuación de la VPC de todos los rasgos funcionales parece señalar que estas comunidades ficoperifíticas no tienen limitaciones de recursos, la competencia es reducida y las especies tienden a ser funcionalmente diferentes. Las variables ambientales con mayor influencia fueron el caudal, la mineralización del agua, el pH y la transparencia. La presencia de mucílago se asoció con la dureza del agua y el predominio de algas filamentosas con la transparencia; el pH influyó positivamente la relación superficie/volumen (S/V). Conclusiones: Este estudio constituye una línea base que permitirá evaluar cambios en las comunidades de algas bentónicas ante posibles intervenciones y brindar pautas para eventuales acciones de restauración de los sistemas fluviales de esta región de importancia mundial por su elevada biodiversidad.

Introduction: Knowledge on the periphytic community is essential because of its central role in river primary production. Also, periphyton is a valuable bioindicator of the community. However, to the date, little is known about the functional ecology of these communities in Colombian rivers. Objective: This work sought to characterize functional aspects of the phycoperiphytic community of four lotic systems of the La Planada Natural Reserve, located in the Department of Nariño, Colombia. Methods: In May 2019, between one and three sampling sites were established in each river. Hydrological and physicochemical variables were measured. Periphyton was sample to determine the taxonomic composition of the benthic algae as well as some functional traits. From these traits, the community weighted mean (CWM) and community weighted variance (CWV) were calculated, and their relation with abiotic variables was explored using regressions, correlations, and a canonical correspondence analysis (CCA). Results: 59 genera of algae were recorded, from which 47 had its functional traits measured. The CWM of the siliceous exoskeleton trait was statistically higher in El Tejón creek. The other traits had similar CWM and CWV values in all rivers. However, the traits of the presence of mucilage and organization in filaments showed predominance in some streams. The fluctuating data of CWV in all rivers seem to indicate that these phycoperiphytic communities have no resource limitations, competition is low, and species tend to be functionally different. The environmental variables with the greatest influence were flow, water mineralization, pH, and water transparency. The hardness of the water and the presence of mucilage were associated, while the predominance of filamentous algae was related to transparency; pH positively influenced the surface/volume ratio (S/V). Conclusions: This study represents a baseline that will allow evaluating changes in the benthic algae communities in the face of possible interventions and providing guidelines for eventual actions to restore the river systems of this important region due to its high biodiversity.

Biofilm-forming capacity of two benthic microalgae, Navicula incerta and Navicula sp., on three substrates (Naviculales: Naviculaceae)

Benthic microalgae have the natural capacity to adhere to a diversity of fixed submerged substrates to form biofilms, which have important roles not only in natural ecosystems, but also in aquaculture systems. An experimental investigation was performed to assess the biofilm-forming capacity of two microalgae (Navicula incerta and Navicula sp.) on three different substrates (plastic net, fabric, and wood) under controlled temperature and light conditions. The substrates were arranged on curtains suspended from a wood stick, into plastic aquariums (45 L in capacity) filled with filtered marine water enriched with F/2 medium. The trial was carried out until the exponential growing phase of the microalgae was reached. After that, the incorporated biomass was gravimetrically calculated, and its biochemical composition was determined by standard methods. The greatest amount of incorporated dry matter was observed for Navicula sp. on fabric and the lowest was observed for wood. The highest number of cells associated with the biofilm was obtained for Navicula sp. on the plastic net (1.24 x 109 cells/m2), while the lowest was recorded for Navicula sp. on the wood (1.43 x 108 cells/m2). Significant differences in organic matter were found among the substrates, with the highest values for N. incerta on the fabric (3.22 g/m2) and the lowest for Navicula sp. on the wood (0.02 g/m2). The best biochemical profiles among the formed biofilms were observed for N. incerta on the plastic net and Navicula sp. on the fabric. The plastic net was considered the best substrate because of the stability of the biofilm and the easiness of harvesting the biomass.

Las microalgas bentónicas tienen la capacidad natural de adherirse a diversos sustratos fijos sumergidos para formar biopelículas, las cuales tienen roles importantes no solo en ecosistemas naturales sino también en sistemas de producción acuícolas. Se llevó a cabo una investigación experimental para evaluar la capacidad formadora de biopelículas de dos microalgas bentónicas (Navicula incerta y Navicula sp.) en tres diferentes sustratos (malla plástica, tela y madera), bajo condiciones controladas de temperatura y luz. Los sustratos fueron arreglados a manera de cortinas suspendidas de un tubo de PVC dentro de acuarios de plástico (45 L de capacidad) con agua marina enriquecida con el medio F/2. El experimento se llevó hasta que la fase de crecimiento exponencial de la microalga fue alcanzada. Posteriormente la biomasa incorporada fue calculada gravimétricamente, y su composición bioquímica fue determinada por métodos estándar. La mayor cantidad de materia seca se observó para N. incerta en el sustrato de tela y la menor se encontró en el de madera. El mayor número de células asociadas a la biopelícula fue registrado para Navicula sp. en malla plástica (1.24 x 109 cel/m2), mientras que el menor se encontró para Navicula sp. en madera (1.43 x 108 cels/m2). Diferencias significativas en cuanto a materia orgánica se encontraron entre los sustratos y las especies, con valores más altos para N. incerta en tela (3.22 g/m2) y más bajos para Navicula sp. en madera (0.02 ± 0.05 g/m2). Los mejores perfiles bioquímicos para las biopelículas correspondieron a las formadas por N. incerta sobre malla plástica y Navicula sp. sobre tela. La red de plástico se consideró el mejor sustrato debido a la estabilidad de la biopelícula y la facilidad para cosechar la biomasa.

Variación espacial de la diversidad del macrobentos en la Reserva Marina El Pelado / Spatial variation of the macrobenthos diversity in the El Pelado Marine Reserve / Variação espacial da diversidade macrobêntica na Reserva Marinha de El Pelado

Resumen Introducción: La Reserva Marina El Pelado es una importante área protegida de la costa ecuatoriana debido a la conectividad que tiene con otras áreas marinas protegidas. Objetivo: Identificar patrones de variación espacial en la estructura comunitaria del macrobentos de fondos someros. Materiales y Métodos: Se muestrearon diez sitios en la zona cercana a la costa y al Islote El Pelado. La abundancia de macroinvertebrados y organismos sésiles se estimó visualmente mediante buceo a lo largo de dos transectos en banda paralelos a la costa. Cada transecto fue de 50 m de longitud y 5 m de ancho, con una superficie total de 500 m2 por localidad. Se registró salinidad, pH, cloro residual, oxígeno, material flotante, coliformes fecales, mercurio, aceites y grasas en la superficie del mar. Resultados: Se identificaron 92 especies (86 especies de invertebrados y 6 especies de macroalgas); el grupo mejor representado fue el de los cnidarios con 31 especies de 13 familias, seguido de los moluscos con 15 especies de 11 familias. Las especies con mayores abundancias media fueron de macroinvertebrados Echinometra vanbrunti (21.54%), de organismos sésiles Bugula californica (34.2%). Conclusiones: No se encontraron diferencias significativas en la diversidad, riqueza y equidad de especies del macrobentos entre las zonas de estudio.

Abstract Introduction: The El Pelado Marine Reserve is an important protected area of the Ecuadorian coast due to the connectivity it has with other marine protected areas. Objective: Identify patterns of spatial variation in the community structure of shallow fund macrobenthos. Materials and Methods: Ten sites were sampled in the area near the coast and the El Pelado Islet. The abundance of macroinvertebrates and sessile organisms was estimated visually by diving along two parallel transects parallel to the coast. Each transect was 50 m long and 5 m wide, with a total area of 500 m2 per location. Salinity, pH, residual chlorine, oxygen, floating material, fecal coliforms, mercury, oils and fats were recorded on the sea surface. Results: 92 species were identified (86 species of invertebrates and 6 species of macroalgae); the best represented group was the cnidarians with 31 species from 13 families, followed by the molluscs with 15 species from 11 families. The species with higher average abundances were of macroinvertebrates Echinometra vanbrunti (21.54%), sessile organisms Bugula californica (34.2%). Conclusions: No significant differences were found in the diversity, richness and equity of macrobenthic species between study areas.

Resumo Introdução: A Reserva Marinha El Pelado é uma importante área protegida da costa equatoriana, devido à conectividade que tem com outras áreas marinhas protegidas. Objetivo: Identificar padrões de variação espacial na estrutura da comunidade de macrobentos fundos rasos. Materiais e Métodos: Dez locais foram amostrados na área próxima à costa e na Ilhota de El Pelado. A abundância de macroinvertebrados e organismos sésseis foi estimada visualmente mergulhando-se ao longo de dois transectos paralelos paralelos à costa. Cada transecto tinha 50 m de comprimento e 5 m de largura, com uma área total de 500 m2 por localização. Salinidade, pH, cloro residual, oxigênio, material flutuante, coliformes fecais, mercúrio, óleos e gorduras foram registrados na superfície do mar. Resultados: foram identificadas 92 espécies (86 espécies de invertebrados e 6 espécies de macroalgas); O grupo mais bem representado foi o de cnidários com 31 espécies de 13 famílias, seguido dos moluscos com 15 espécies de 11 famílias. As espécies com maior abundância média foram de macroinvertebrados Echinometra vanbrunti (21,54%), organismos sésseis Bugula californica (34,2%). Conclusões: Não foram encontradas diferenças significativas na diversidade, riqueza e equidade das espécies macrobênticas entre as áreas de estudo.

Seasonal and ontogenetic diet patterns of the freshwater pufferfishColomesus asellus (Müller & Troschel, 1849) in the upper-middleTocantins River / Padrões sazonais e ontogenéticos da dieta do baiacu de água doce Colomesus asellus(Müller & Troschel, 1849) no alto-médio rio Tocantins

We described the feeding habits of Colomesus asellus from riverbanks of the upper-middleTocantins River, Central Brazil. Two sampling expeditions were carried out in August (dry season) and inOctober (rainy season) of 2013, downstream from the Lajeado Hydroelectric Power Plant, Tocantins state.The diet of C. asellus was characterized and compared between juveniles and adults and betweenindividuals captured in the dry season and in the rainy season. Individuals exhibited marked temporalsegregation, with a predominance of adults on the riverbanks during the dry season and the predominanceof juveniles in the rainy season. The diet of this species was based on diverse benthic prey, mostlyEphemeroptera nymphs (Insecta). Contrary to our expectations, the diet composition of C. asellus was notinfluenced by seasonal changes or ontogenetic factors, but the size of individuals determined the numberof prey consumed. Thus, C. asellus can be classified in its trophic ecology as an insectivore without relationwith fish size and seasonality.

Descrevemos os hábitos alimentares de Colomesus asellus capturados nas margens do rioTocantins, Brasil Central. Duas expedições de coleta foram realizadas em agosto (estação seca) e emoutubro (estação chuvosa) de 2013, a jusante da Usina Hidrelétrica de Lajeado, Estado do Tocantins. Adieta de C. asellus foi caracterizada e comparada entre juvenis e adultos e entre indivíduos capturados naestação seca e na estação chuvosa. Os indivíduos apresentaram marcada segregação temporal, compredominância de adultos nas margens do rio durante a estação seca e predominância de juvenis na estaçãochuvosa. A dieta desta espécie foi baseada em diversas presas bentônicas, principalmente ninfas deEphemeroptera (Insecta). Contrariamente às nossas expectativas, a composição da dieta de C. asellus não foiinfluenciada por mudanças sazonais ou fatores ontogenéticos, mas o tamanho dos indivíduos determinou onúmero de presas consumidas. Assim, a espécie pode ser classificada como insetívora, sem variação em suaecologia trófica relacionada à sazonalidade do ambiente ou ao seu tamanho.

Respuesta ambiental en el Pacífico frente a la subducción de la dorsal asísmica de Cocos (Panamá y Costa Rica) / Environmental response in the Pacific to aseismic Cocos Ridge subduction (Panama and Costa Rica)

Environmental response in the Pacific to aseismic Cocos Ridge subduction (Panama and Costa Rica). The evolution of the marine communities along the Pacific coast of Central America, may have changed in response to the formation of the Isthmus of Panama. To evaluate the effect of the Aseismic Cocos Ridge (DAC) subduction on the marine benthic communities, we reconstructed benthic assemblages from Neogene fossiliferous formations in Burica and Nicoya peninsulas of Panama and Costa Rica. Paleoecological and paleoenvironmental conditions were reconstructed by comparing community structure from bulk fossil samples with dredge collections from modern Tropical American seas, using principal component analysis. Our results indicate that during the early Pliocene, before the closing of the Isthmus, some oceanic islands existed with moderate upwelling in the Burica region. After the closure, during the late Pliocene and early Pleistocene the collision of the DAC caused an uplift of the seafloor, where water depth of 2 300m became shallow waters of less than 40m depth. Meanwhile, upwelling intensified in the open ocean the uplift that had formed small islands in coastal areas of Burica, creating protected areas and limiting the upwelling effect that was given in open ocean. The subduction of the DAC continued until the islands were joined to the mainland and gradually disappeared, allowing the return of the upwelling. During the middle Pleistocene a second process of accelerated uplift ith speeds of 8m/1 000 years provoked again the elevation of the seafloor and later the elevation of the Talamanca Range. The new range formed a barrier that blocked the passage of the Trade winds, created new ecological conditions and optimized and allowed the growth of the best coral reefs in the coasts of the tropical Eastern Pacific (POT) between Panama and Costa Rica. Rev. Biol. Trop. 60 (2): 893-908. Epub 2012 June 01.

Con el fin de evaluar el efecto de la Subducción de la Dorsal Asísmica de Cocos (DAC) durante las etapas finales de la formación del Istmo. Realizamos muestreos con bultos en afloramientos fosilíferos en las penínsulas de Burica y Nicoya. Las condiciones paleoecológicas y paleoambientales fueron reconstruidas a partir de la comparación entre la estructura de las comunidades fósiles, con las comunidades modernas dragadas de los mares de Panamá, usando análisis de componentes principales. Los resultados indican que antes del cierre del Istmo, existieron islas oceánicas y un afloramiento moderado en Burica. Posterior al cierre, el choque de la DAC provocó la elevación del fondo marino y las aguas que se encontraban a 2 300m pasaron a 40m. El afloramiento se intensificaba en mar abierto pero la dorsal había formado islas en Burica que limitaban el efecto del afloramiento en la costa. La subducción de la DAC continuó y las islas se unieron gradualmente a tierra firme y desaparecieron, permitiendo el afloramiento. Durante el Pleistoceno medio un segundo proceso de levantamiento acelerado continuó elevando el fondo marino y formó la Cordillera de Talamanca. La cordillera creó una barrera que bloqueó el paso de los vientos Alisios y originó condiciones ecológicas y optimas que permiten el crecimiento de los mejores arrecifes de coral costeros del Pacífico oriental tropical (POT) entre Panamá y Costa Rica.

Biological monitoring of lotic ecosystems: the role of diatoms / Biomonitoramento dos ecossistemas lóticos: o papel das diatomáceas

Increasing anthropogenic influence on lotic environments as a result of civilisation has captured public interest because of the consequent problems associated with deterioration of water quality. Various biological monitoring methods that provide a direct measure of ecological integrity by using the response of biota to environmental changes have been developed to monitor the ecological status of lotic environments. Diatoms have been used extensively in this regard and this review attempts to summarise the basic concepts associated with biological monitoring using benthic diatoms. Where possible, examples from work carried out in Brazil are used.

O aumento da influência antropogênica sobre ambientes lóticos como resultado da civilização conquistou o interesse público por causa de problemas relacionados com a consequente deterioração da qualidade da água. Vários métodos de biomonitoramento que fornecem uma medida direta da integridade ecológica usando a resposta da biota a alterações ambientais têm sido desenvolvidos para monitorar o estado ecológico de ecossistemas lóticos. Diatomáceas têm sido amplamente utilizadas e esta revisão tenta resumir os conceitos básicos associados ao monitoramento biológico utilizando diatomáceas bentônicas. Sempre que possível, exemplos de trabalhos realizados no Brasil serão utilizados.

Produtos naturais de algas marinhas e seu potencial antioxidante / Natural products from marine seaweeds and their antioxidant potential

Os radicais livres e outros derivados ativos do oxigênio são inevitavelmente co-produzidos em algumas reações biológicas e exercem papel fisiológico importante. No entanto, essas espécies reativas têm sido descritas como fatores que participam diretamente dos mecanismos fisiopatológicos relacionados com a continuidade e as complicações de diversos estados patológicos como a aterosclerose, a diabetes, o câncer, a artrite reumatóide, entre outros. Dessa forma, a terapia antioxidante preveniria o desenvolvimento e a progressão dessas complicações. As algas marinhas representam uma importante fonte de substâncias antioxidantes naturais, uma vez que têm sistemas de defesas antioxidantes bem desenvolvidos. O presente trabalho é uma compilação das pesquisas realizadas sobre a atividade antioxidante de produtos naturais marinhos e extratos de algas marinhas bentônicas.

Free radicals and other reactive species of oxygen are co-produced in some biological reactions and they play important physiological role, and nevertheless they are reported as factors that take straight part in the pathophysiologic mechanism associated with continuity and complications of the several pathological process such as arteriosclerosis, diabetes mellitus, cancer, and arthritis, among others. In this way, the antioxidant therapy should prevent the development and progress of these complications. Seaweeds can be valuable source of natural antioxidant compounds since they have a well-developed antioxidant defense system. The present work is a compilation of the antioxidant activities of marine natural products and benthonic marine seaweeds crude extracts researches.

Benthic Bacillariophyta of the Paripe River estuary in Pernambuco state, Brazil

The aim of this study was to evaluate the benthic diatom composition from the estuary sediment in the Pernambuco State, based on 32 samples. Samples were collected monthly from September through December 1999 (dry period) and from April through July 2000 (rainy period) during four pre established sampling stations. Results indicated 19 families and 31 specific and infraspecific taxa. Eight new records were founded for Pernambuco State: Auliscus coelatus, Fallacia nummularia, Navicula algida, Plagiograma pulchellum, Terpsinoe americana, Triceratium antideluvianna and Tryblionella coarctata and one, Auliscus punctatus Bailey, in northeastern Brazil.

O objetivo do presente estudo foi avaliar a composição das diatomáceas bênticas do sedimento estuarino do estado de Pernambuco, Brasil, com base na análise de 32 amostras. As amostragens foram realizadas mensalmente de setembro a dezembro de 1999 (período seco) e de abril a julho de 2000 (período chuvoso) em quatro estações de coleta previamente estabelecidas. As diatomáceas estiveram representadas por 19 famílias e 31 taxons específicos e infraespecíficos. Ocorreram oito novas citações para o estado de Pernambuco, quais sejam: Auliscus coelatus, Fallacia nummularia, Navicula algida, Plagiograma pulchellum, Terpsinoe americana, Triceratium antideluvianna, Tryblionella coarctata e uma, Auliscus punctatus Bailey, para a região nordeste do Brasil.

Epiphytic diatoms associated with red mangrove (Rhizophora mangle) prop roots in Bahía Magdalena, Baja California Sur, Mexico

The first floristic inventory of benthic diatoms is provided for the Bahia Magdalena-Bahia Almejas lagoon system. Samplings were carried out during November of 1999. The oxydized samples were mounted permanently. Eighty six diatom taxa were identified, out of which 59 are new records for the Bahia Magdalena area, and 12 taxa are new for the Baja California peninsula. Taxa recorded previously as rare in other substrata are common or abundant on the epiphytic macroalgae of mangrove prop roots. Other species are mainly epipelic forms, while 24 are commonly found as tychoplankton in the area. Certain taxa appear to be characteristic of mangrove systems in general.

Se presenta el primer inventario florístico de diatomeas bénticas para el Sistema Lagunar Bahía Magdalena-Bahía Almejas. Se hicieron muestreos en noviembre de 1999. En las muestras oxidadas y montadas permanentemente, se identificaron 86 táxones, de los cuales 59 son nuevos registros para el área de Bahía Magdalena, y 12 son nuevos para la península de Baja California. Táxones previamente registrados como escasos en otros sustratos son comunes o abundantes sobre macroalgas epífitas de raíces primarias de mangle. Otras species son principalmente formas epipélicas, mientras que 24 son constituyentes comunes del ticoplancton del área. Ciertos táxones parecen ser característicos de sistemas de manglar en general.