Se analiza el estudio de la microfauna bentónica y de la micro flora béntica del área de las vías de acceso de la ciudad de Guayaquil que comprende, el Río Guayas, Estero Salado, Canales del Morro y de Jambelí, Estero del Muerto y los puentes internos de la ciudad. La microfauna bentónica debido a la gran sedimentación y por las condiciones anóxicas del área al quedarse sepultados y/o fragmentados estuvieron ausentes en unos casos y en otros con representantes muy aislados. En cambio la microflora béntica tuvo una población más frecuente a pesar de la gran turbidez del área, sin embargo y debido a la gran cantidad de restos vegetales son llevados por las corrientes y de esta manera tiene la capacidad de renovar el oxígeno del agua muy vital para el desarrollo de las especies. | A research study about benthonic microflora and microfauna from waters around Guayaquil city, which includes Guayas river, el Morro and Jambelí channels, el Muerto estuary, as well as internal bridges of the city, is carried out. Benthonic microfauna were absent due to the anoxic conditions of waters and also due to high sedimentation of the area which produced the fragmentation and interment of organisms. On the other hand, the benthonic microflora showed a more frequent population in spite of the high turbidness of waters; however, and due to high quantity of vegetals carried by water currents, the aquatic environment has the capacity to renew the oxygen of waters which is essential for species development. | Incluye ref.bibl., grafs. | Published

The malacological fauna of the Agua Dulce/El Ermitaño lagoon estuarine system was characterized and its relation to some environmental parameters determined. Five samplings were carried out in January, August, October and December 1993, and February 1994. Biological, hydrological and sediment samples were taken at seven stations in each water body of the system, located on the northern coast of the state of Jalisco (Mexico). The values of some physical and chemical parameters were recorded and differences were found between both water bodies, mainly in regard to salinity, as an average value of 27 psu was obtained for Agua Dulce lagoon and of 2 psu for El Ermitaño estuary. The qualitative analysis of the sediments showed that the system is made up of four basic types: sandy silt, clayey silt, fine to medium sand and a small part of rocky substrate. The malacological fauna was composed of two classes, Gasteropoda and Bivalvia, the first being the one that presented a greater number of species; 6,782 live organisms and 18,508 dead organisms were collected, corresponding to 17 species of gastropods and 14 bivalves. Of the 31 species collected, only 9 were found alive and some appeared in both water bodies in spite of the salinity gradient recorded in the system. Groups of representative species were identified for four types of environments (marine, >25 psu; euryhaline, 10–18 psu; brackish, 5–10 psu; and freshwater, 0–5 psu). Finally, the most important species were the bivalves Tagelus longisinuatus and Mytella strigata, and the gastropods Rissoella excolpa and Bittium mexicanum, with the highest abundances of the cycle. Low diversity values were obtained (D = 1.5–1.8, Dmax = 2.5); however, they were within those recorded for tropical and subtropical coastal ecosystems.

The malacological fauna of the Agua Dulce/El Ermitaño lagoon estuarine system was characterized and its relation to some environmental parameters determined. Five samplings were carried out in January, August, October and December 1993, and February 1994. Biological, hydrological and sediment samples were taken at seven stations in each water body of the system, located on the northern coast of the state of Jalisco (Mexico). The values of some physical and chemical parameters were recorded and differences were found between both water bodies, mainly in regard to salinity, as an average value of 27 psu was obtained for Agua Dulce lagoon and of 2 psu for El Ermitaño estuary. The qualitative analysis of the sediments showed that the system is made up of four basic types: sandy silt, clayey silt, fine to medium sand and a small part of rocky substrate. The malacological fauna was composed of two classes, Gasteropoda and Bivalvia, the first being the one that presented a greater number of species; 6,782 live organisms and 18,508 dead organisms were collected, corresponding to 17 species of gastropods and 14 bivalves. Of the 31 species collected, only 9 were found alive and some appeared in both water bodies in spite of the salinity gradient recorded in the system. Groups of representative species were identified for four types of environments (marine, >25 psu; euryhaline, 10-18 psu; brackish, 5-10 psu; and freshwater, 0-5 psu). Finally, the most important species were the bivalves Tagelus longisinuatus and Mytella strigata, and the gastropods Rissoella excolpa and Bittium mexicanum, with the highest abundances of the cycle. Low diversity values were obtained (D = 1.5-1.8, Dmax = 2.5); however, they were within those recorded for tropical and subtropical coastal ecosystems. | Se caracterizó la fauna malacológica del sistema lagunar estuarino Agua Dulce/El Ermitaño y su relación con algunos parámetros ambientales. Para esto se llevaron a cabo cinco muestreos durante los meses de enero, agosto, octubre y diciembre de 1993, así como febrero de 1994. Las muestras biológicas, hidrológicas y de sedimentos se tomaron en siete estaciones de muestreo en cada cuerpo de agua del sistema, que se localiza en la costa norte del Estado de Jalisco (México). Los valores de algunos parámetros fisicoquímicos fueron registrados y se encontraron diferencias entre los dos cuerpos de agua, sobre todo en lo que respecta a la salinidad, obteniendo para la laguna Agua Dulce un valor promedio de 27 ups y para el estero El Ermitaño un valor promedio de 2 ups. El análisis cualitativo de los sedimentos mostró que el sistema está compuesto por cuatro tipos básicos: limo arenoso, limo arcilloso, arena media a fina y una pequeña parte de sustrato rocoso. La fauna malacológica encontrada estuvo compuesta por dos clases, Gasteropoda y Bivalvia, siendo la primera la que presentó un mayor número de especies. Se recolectaron 6,782 organismos vivos y 18,508 muertos, los cuales correspondieron a 17 especies de gasterópodos y 14 de bivalvos. De las 31 especies encontradas, sólo 9 se recolectaron vivas, existiendo algunas que se presentaron en ambos cuerpos de agua a pesar del gradiente de salinidad que se registró en el sistema. Se encontraron grupos de especies representativos para cuatro tipos de ambientes (marino, >25 ups; eurihalino, 10 a 18 ups; salobre, 5 a 10 ups; y dulceacuícola, 0 a 5 ups). Por último, las especies más relevantes fueron los bivalvos Tagelus longisinuatus y Mytella strigata, y los gasterópodos Rissoella excolpa y Bittium mexicanum, las cuales presentaron las abundancias más altas del ciclo. Se presentaron valores bajos de diversidad (D = 1.5 a 1.8, Dmáx = 2.5); sin embargo, éstos se mantuvieron dentro de los registrados para ecosistemas costeros tropicales y subtropicales.

Para la implementación de la Directiva Marco del Agua (DMA, Directiva 2000/60/CE) es necesario establecer un protocolo estandarizado de muestreo y análisis que sirve para la evaluación de la calidad biológica mediante la fauna bentónica. En este trabajo se ha llevado a cabo un estudio comparativo de diversos protocolos de macroinvertebrados que se utilizan en España y en Europa (AQEM, EPA, Gudalmed). Valorando los tres protocolos con una lista de 12 criterios, el protocolo Guadalmed se adecuan mejor a la mayoría de ellos, por lo que aparece como una herramienta eficaz en la determinación del estado ecológico

Sosa Castillo, A. C. (2013). Calidad del agua y la diversidad de macrobentos en dos esteros como aporte al manejo de recurso costero en Limón- Costa Rica. [Tesis de Maestría]. Universidad Nacional, Puntarenas, C.R. | La importancia de la calidad, del agua y la utilización de organismos vivos para la detección de perturbaciones en diversos ecosistemas se ha ido ampliando a nivel mundial. Sin embargo, no existen índices bióticos para determinar la calidad del agua en estuarios a diferencia de los sistemas loticos que tienen varios establecidos. En los estuarios, por lo general se realizan estudios para buscar cambios en las condiciones físico-químicas y microbiológicas, los cuales, generan cambios en la biota y a partir de estos, se establecen propuestas de bioindicadores. Para los esteros Negro y Vizcaya ubicados en la provincia de Limón en Costa Rica, no existen estudios reportados con este tipo de orientación. Por lo tanto, se realizó este estudio como aporte al conocimiento del estado de contaminación del agua y a su vez, asociarlo a la comunidad macrobentica presente, con la finalidad de proponer posibles bioindicadores como componente integral para el manejo de los esteros. En los meses de setiembre, octubre, enero y marzo del 2010-2011 se realizaron muestreos en 16 estaciones, ocho en cada estero. Las muestras biológicas fueron tamizadas in situ y se conservaron. Posteriormente se identificaron los especímenes hasta el nivel más bajo posible y se contaron. A partir de los resultados, se encontraron 592 especímenes distribuidos en tres grupos: Mollusca, Polychaeta y Crustácea. El grupo que presentó mayor cantidad de individuos fue Mollusca con 304 y la familia más abundante fue Dreissenacea; seguido por Polychaeta con 285 individuos y la familia con más individuos fue Nereidae con 155. Por último, el grupo Crustácea con 3 individuos pertenecientes a las familias Xanthidae, Balanidae y Portunidae. Los parámetros físico-químicos profundidad, temperatura, coliformes fecales y nitratos influyeron en la presencia espacio-temporal de las especies encontradas en los dos sitios. Los valores de coliformes no fueron críticos en algunas estaciones. Los rangos de coliformes fecales estuvieron entre los 2 NMP hasta los 920 NMP y coliformes totales entre los 2 NMP y los 2400 NMP. Por otro lado, Estero Negro presentó mayores valores de coliformes fecales y totales que estero Vizcaya durante los cuatro meses muestreados. La familia Capitellidae es recomendada como potencial bioindicador de contaminación con los tres géneros identificados: Aciculatus, Heteromastus y Capitella para Estero Negro. Adicionalmente se realizaron entrevistas a pobladores y turistas de la zona de estudio con la intención de conocer su punto de vista acerca del estado ambiental de los esteros. Los entrevistados opinaron que es necesario hacer este tipo de estudios para mejorar la calidad de vida y realizar estudios dirigidos a Ja calidad de agua en el estero sería un beneficio que brindaría conocimiento general. Por otro lado, estero Negro, presentó durante el periodo de estudio contaminación microbiológica puntual espaciotemporal. Se recomienda el ecoturismo como alternativa para disminuir los impactos negativos y económicos para la población residente de estero Vizcaya y estero Negro. | The importance of water quality and the use of life organisms for the detection of perturbations in several ecosystems has been gaining ground on a worldwide level. Nonetheless, there are no biotic indices to determine water quality in estuaries, unlike lotic systems for which there are many. The type of studies generally carried in estuaries try to pinpoint changes in the microbiological and/or physicochemical conditions, which jn turn affect the biota and can lead to establishing proposals for bioindicators. There are no reported studies applying this kind of methodology for the estuaries Negro and Vizcaya located in the Limon province in Costa Rica. Hence, this study came to be as a means to gage the state of the water contamination, and in time, to link it to the macrobhenthic community present, with the end goal of proposing possible bioindicators as •an integral component in the management of the estuaries. In the months of september, october, january and march of 2010-2011, sampling was carried out in 16 stations, eight in each estuary. The biological samples were framed in situ and preserved. At a later time, the specimens present were identified down to the lowest possible level and then counted. From this result, 592 specimens were found distributed amongst three groups: Mollusca, Polychaeta and Crustacea. The group where the largest amount of individuals present was Mollusca with 304 and the most abundant family was Dreissenacea; followed by Polychaeta with 285 individuals and with the most abundant family Nereidae with 155. Finally the Crustacea group had 3 individuals belonging to the families Xanthidae, Balanidae y Portunidae. The physicochemical parameters depth, temperature, fecal coliform s and nitrates influenced in the timespace presence of the species found on both places. The coliform s values were not critical in some of the stations. The ranges for fecal coliform s were between the 2 NMP up to 920 NMP, and the total coliform s ranged between 2 NMP and 2400 NMP. On the other hand, estuary Negro presented high values of fecal and total coliform s than estuary Viscera during the four months sampled. The family Capitellidae is recommended as a possible bioindicador of the contamination with the identified genus: Aciculatus, Heteromastus and Capitella for Estuary Negro. Additionally, inhabitants and tourists were interviewed in the area studied with the purpose of analyzing their point of view on the environmental state of the estuaries. The general consensus was that this type of study is needed to improve the quality of life and that studies directed to targeting water quality would bring general benefit to the overall knowledge; since estuary Negro presented time-space punctual microbiological contamination during the sampling period. Ecotourism is recommended as an alternative towards diminishing the negative and economic impacts for the human population residing in the vicinity of estuaries Vizcaya and Negro. | Universidad Nacional, Costa Rica | Escuela de Ciencias Biológicas

Diatoms are useful ecological indicators because they are found in abundance in most lotic ecosystems. The use of diatoms as indicators of the quality of river waters is widely accepted based on the fact that all diatom species have optima with respect to their tolerance for environmental conditions such as nutrients, organic pollution, pH, etc. Moreover diatoms are indicators of pollution in short term compared with other groups eg. macroinvertebrates. The rivers and streams of the Pampean plain, in Buenos Aires Province, are subjected to different human impacts. The most important stresses on rivers and streams in the Pampean plain are organic enrichments (discharge of insufficiently treated sewage), nutrients, heavy metals, pathogenic agents, pesticides, herbicides and physical changes produced by dredging and canalisation. The bottom substrate is mostly composed of slime-clay with low proportions of gravel and sand; in consequence, the epipelon is the most represented benthic community and suitable for biomonitoring purposes because it allows for comparing similar substrates along the rivers and streams. The aim of this study is to summarise the most common methodologies used in biomonitoring with diatoms and the application of biotic indices (diversity and pollution indices) in the evaluation of water quality of rivers and streams from the Pampean plain. | Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) - Instituto de Limnología "Dr. Raul A. Ringuelet" (ILPLA)

Diatoms are useful ecological indicators because they are found in abundance in most lotic ecosystems. The use of diatoms as indicators of the quality of river waters is widely accepted based on the fact that all diatom species have optima with respect to their tolerance for environmental conditions such as nutrients, organic pollution, pH, etc. Moreover diatoms are indicators of pollution in short term compared with other groups eg. macroinvertebrates. The rivers and streams of the Pampean plain, in Buenos Aires Province, are subjected to different human impacts. The most important stresses on rivers and streams in the Pampean plain are organic enrichments (discharge of insufficiently treated sewage), nutrients, heavy metals, pathogenic agents, pesticides, herbicides and physical changes produced by dredging and canalisation. The bottom substrate is mostly composed of slime-clay with low proportions of gravel and sand; in consequence, the epipelon is the most represented benthic community and suitable for biomonitoring purposes because it allows for comparing similar substrates along the rivers and streams. The aim of this study is to summarise the most common methodologies used in biomonitoring with diatoms and the application of biotic indices (diversity and pollution indices) in the evaluation of water quality of rivers and streams from the Pampean plain. | Diatoms are useful ecological indicators because they are found in abundance in most lotic ecosystems. The use of diatoms as indicators of the quality of river waters is widely accepted based on the fact that all diatom species have optima with respect to their tolerance for environmental conditions such as nutrients, organic pollution, pH, etc. Moreover diatoms are indicators of pollution in short term compared with other groups eg. macroinvertebrates. The rivers and streams of the Pampean plain, in Buenos Aires Province, are subjected to different human impacts. The most important stresses on rivers and streams in the Pampean plain are organic enrichments (discharge of insufficiently treated sewage), nutrients, heavy metals, pathogenic agents, pesticides, herbicides and physical changes produced by dredging and canalisation. The bottom substrate is mostly composed of slime-clay with low proportions of gravel and sand; in consequence, the epipelon is the most represented benthic community and suitable for biomonitoring purposes because it allows for comparing similar substrates along the rivers and streams. The aim of this study is to summarise the most common methodologies used in biomonitoring with diatoms and the application of biotic indices (diversity and pollution indices) in the evaluation of water quality of rivers and streams from the Pampean plain.