[Typing and evaluation of hydrocarbon-degrading activity of a bacterial strain isolated from the Bahía Blanca estuary, Argentina]. / Tipificación y evaluación de la actividad degradadora de hidrocarburos de una cepa bacteriana aislada del estuario de Bahía Blanca, Argentina.

During screening for oil-degrading bacteria in sediments of Bahía Blanca estuary, a bacterial strain was isolated which uses a limited number of organic compounds, especially lineal hydrocarbons. The goals of this study were to characterize the strain and to evaluate its activity on crude oil. Based on phenotypic characteristics and the analysis of 16S rDNA sequences, it was determined that the strain is strongly related to Alcanivorax borkumensis. The strain was cultured, under quasicontinuous conditions, with crude oil as sole source of carbon and energy. After 30 days of incubation, n-alkane decrease reached 86%. The isoalkanes pristane and phitane were degraded more slowly, but a decrease of about 63% was obtained. The strain studied would be useful for the bioremediation of the local coasts, so that this study will be continued in order to obtain its successful application in the environment.

Tipificación y evaluación de la actividad degradadora de hidrocarburos de una cepa bacteriana aislada del estuario de Bahía Blanca, Argentina / Typing and evaluation of hydrocarbon-degrading activity of a bacterial strain isolated from the BahÝa Blanca estuary, Argentina

During screening for oil-degrading bacteria in sediments of BahÝa Blanca estuary, a bacterial strain was isolated which uses a limited number of organic compounds, especially lineal hydrocarbons. The goals of this study were to characterize the strain and to evaluate its activity on crude oil. Based on phenotypic characteristics and the analysis of 16S rDNA sequences, it was determined that the strain is strongly related to Alcanivorax borkumensis. The strain was cultured, under quasicontinuous conditions, with crude oil as sole source of carbon and energy. After 30 days of incubation, n-alkane decrease reached 86. The isoalkanes pristane and phitane were degraded more slowly, but a decrease of about 63 was obtained. The strain studied would be useful for the bioremediation of the local coasts, so that this study will be continued in order to obtain its successful application in the environment.

Water quality for aquaculture development in Bahía Blanca estuary, Argentina. Bacteriological studies.

The present bacteriological report is part of an institutional multidisciplinary research project designed to study the factibility of using a tidal channel, located in the southern part of the Canal Principal in Bahía Blanca Estuary for aquaculture. Three sampling stations were located. Samples were taken in six opportunities from both water and sediments. Bacteriological studies from water included quantification of heterotrophic marine bacteria, heterotrophic terrestrial bacteria, total coliforms, Escherichia coli and Pseudomonas aeruginosa. Escherichia coli and hydrocarbon-degrading bacteria were quantified from sediments. It is important to include the latter physiological group since their size reflects the presence and fluctuations of this type of pollutant in the environment. The evaluation of faecal indicator values leads to the conclusion that the organic matter present in the studied area, does not come directly from the domestic sewage. The bacteriological data suggest that the studied area would be suitable for aquaculture. Nevertheless, further monitorings contributing to detected modifications in the present bacteriological conditions are recommended.

Water quality for aquaculture development in Bahía Blanca estuary, Argentina. Bacteriological studies

El presente estudio bacteriológico forma parte de un proyecto de investigación institucional multidisciplinario. Tiene por objetivo estudiar la factibilidad de utilizar para acuicultura, un canal de marea, localizado al sur del Canal Principal del Estuario de Bahía Blanca. Se establecieron tres estaciones de muestreo a las que se accedió en seis oportunidades. De cada una de ellas se extrajeron muestras de agua subsuperficial y sedimentos superficiales. En las aguas se cuantificaron bacterias heterótrofas marinas, bacterias heterótrofas terrestres, coliformes totales, Escherichia coli y Pseudomonas aeruginosa, y en los sedimentos Escherichia coli y bacterias degradadoras de hidrocarburos. Se considera importante la inclusión de este último grupo fisiológico debido a que refleja la presencia y fluctuaciones de este tipo de contaminante en el ambiente. La evaluación de los resultados de los indicadores fecales lleva a concluir que la materia orgánica, presente en la zona, no llega directamente de los desagües cloacales que afectan otras áreas del estuario. A partir de los resultados bacteriológicos se considera factible el empleo de la zona estudiada, si bien se deberían continuar los monitoreos a fin de detectar cualquier modificación en las condiciones bacteriológicas actuales

Estudio bacteriológico de aguas marinas para uso recreacional / Bacteriological surveillance of a seawater swimming pool

A fin de decidir la habilitación de una pileta de agua de mar destinada a uso recreacional, la Municipalidad de Bahía Blanca solicitó determinar la calidad bacteriológica de sus aguas. Esto se debió a que la pileta se abastece con agua de la bahía Blanca, que en ese sector del Canal Principal no es apta para baño, como se pudo comprobar en estudios anteriores. Durante tres temporadas estivales se efectuó un estudio integral de las aguas que alimentan la pileta y un monitoreo de la misma. La caracterización se hizo mediante la cuantificación de los grupos bacterianos de heterótrofas aerobias viables, de origen marino y terrestre, coliformes totales, Escherichia coli y Pseudomonas productoras de fluorescencia. Se registraron: temperatura, salinidad, pH del agua y parámetros meteorológicos. En todos los casos los recuentos de indicadores de contaminación fecal, tanto del agua ingresante como de los controles realizados en piletas, estuvieron por debajo de los estándares más rigurosos que existen a nivel mundial para aguas de baño. El trabajo pone en evidencia que en este sistema de planicies de marea no es válida la extrapolación de resultados, y que las condiciones actuales se mantendrán mientras no se produzcan alteraciones en la zona que tiene influencia sobre las planicies de marea adyacentes al balneario

[Bacteriological study of seawater for recreational use]. / Estudio bacteriológico de aguas marinas para uso recreacional.

A study was conducted at the request of the authorities of the Municipality of Bahía Blanca city, in order to decide whether the sea-water of a swimming pool was suitable for recreational purposes. The characterization of the water was performed through bacteriological indicators and the following groups of bacteria were studied: marine and terrestrial viable aerobic heterotrophic bacteria; total coliforms; Escherichia coli and fluorescent Pseudomonads. Salinity, temperature and pH were registered together with meteorological parameters. In every case, the bacteriological values obtained were lower than those of the most strict international standards used worldwide for bathing waters. In this way, the particular dynamic processing of the water entering the swimming pool from Blanca Bay becomes important, since previous studies conducted on the water of its Principal Channel had yielded high bacteriological values which rendered it unsuitable for bathing. This work shows that in this tidal-flats system, extrapolation of results is not valid. These conditions will remain the same if other factors do not change in the tidal-flats that surround the swimming pool.

Relationship of physical factors and salinity with indicator bacteria in Bahía Blanca estuary waters, Argentina.

The relationship between the number of Escherichia coli, terrestrial and marine heterotrophic bacteria, with certain physical and chemical parameters in Bahia Blanca estuary waters, were investigated by means of a statistical analysis of multiple linear regression. The samples were taken during a period of 16 months. Although distance from the sewage outlet seems to be the factor having the greatest effect on the number of alien bacteria, the models obtained for E. coli are inappropriate to predict bacterial behaviour in this particular natural habitat, while for heterotrophic bacteria descriptive models were selected. The results of this study suggest that many factors affect bacterial population densities in this estuarine ecosystem. This should be taken into account trying to solve the problem in order to avoid progressive degradation.

Relationship of physical factors and salinity with indicator bacteria in Bahía Blanca estuary waters, Argentina

The relationship between the number of Escherichia coli, terrestrial and marine heterotrophic bacteria, with certain physical and chemical parameters in Bahia Blanca estuary waters, were investigated by means of a statistical analysis of multiple linear regression. The samples were taken during a period of 16 months. Although distance from the sewage outlet seems to be the factor having the greatest effect on the number of alien bacteria, the models obtained for E. coli are inappropriate to predict bacterial behaviour in this particular natural habitat, while for heterotrophic bacteria descriptive models were selected. The results of this study suggest that many factors affect bacterial population densities in this estuarine ecosystem. This should be taken into account trying to solve the problem in order to avoid progressive degradation.

Deteccíon bacteriológica de contaminacíon por petróleo en el estuario de Bahía Blanca / Bacteriological detection of crude oil contamination in the Bahía Blanca estuary

Para conocer la deriva y determinar el área afectada por las pérdidas de petróleo producidas durante las tareas de transvasamiento mediante Boyas Suecas, se cuantificaron bacterias degradadoras de petróleo por el método del Número Más Probable en sedimentos superficiales del estuario de Bahía Blanca. Se establecieron diez estaciones intermareales de nuestreo, localizadas entre las boyas 21 y 16. Se realizó el recuento de bacterias heterótrofas aerobias marinas sobre Agar Marine 2216, y la determinación de materia orgánica. De acuerdo a la abundancia de bacterias degradadoras, el análisis estadístico diferenció dos zonas con distinto grado de contaminación. Una comprendida por las estaciones ubicadas en el Canal Principal de navegación, con recuentos medios, expresados en log10, de 2,98 a 3,65 bactérias/g de sedimento seco, y la otra con valores de 4,16 a 4,37, que se interna en canales y arroyos del veril sur. Estos resultados indican una deriva del contaminante en sentido perpendicular al Canal Principal, debido a la influencia de los vientos predominantes con dirección N y NNO. Mediante el análisis de regresión lineal simple se estableció una relación altamente significativa de la materia orgánica con los dos grupos bacterianos. Este estudio señala que el petróleo proveniente de los volcados está afectando zonas productivas del estuario

[Bacteriological detection of crude oil contamination in the Bahía Blanca estuary]. / Detección bacteriológica de contaminación por petróleo en el estuario de Bahía Blanca.

In order to evaluate the distribution of occasional oil spills produced by floating system for transferring crude oil, the number of hydrocarbon-degrading bacteria was counted in superficial sediments from Bahía Blanca Estuary, using the Most Probable Number method. Sediment were collected from ten stations located between buoys 21 and 16. Heterotrophic aerobic marine bacteria were counted on Marine Agar 2216. Determination of organic carbon was also carried out. On the base of the number of hydrocarbon-degrading bacteria, statistical analysis differentiated two zones with different degree of pollution, one including the stations of the Principal Channel, with average values, expressed as log10, which ranged from 2.98 to 3.65 bacteria/g of dry sediment, and the other from 4.16 to 4.37, located in small channels on the Southern coast. These results suggest a drift of the oil perpendicular to the Principal Channel, probably caused by the action of predominant winds with direction N, NNW. A linear regression analysis determined highly significant relationship between organic carbon and both bacterial groups. This study shows that the spilled oil is affecting productive zones of the estuary.

[Persistence of Escherichia coli in estuarine sediments]. / Persistencia de Escherichia coli en sedimentos estuarinos.

In order to establish the extension of fecal pollution, as well as the persistence of the indicator bacterium Escherichia coli, a bacteriological survey of the Bahía Blanca estuary sediments was done during the period August 1987-October 1988. Thirty two sampling stations were established in which sediment columns of 70 cm in length were extracted. The microbiological analysis revealed the amplitude of the area affected by industrial and sewer effluents and the viability of fecal coliforms up to 70 cm levels.

[Spatial and temporal distribution of aerobic bacteria in the Bahía Blanca estuary, Argentina]. / Distribución espacial y temporal de bacterias aerobias en el estuario de Bahía Blanca, Argentina.

In order to study the baseline of the present bacteriological state in Bahia Blanca estuary (4) (Fig. 1 ), 13 sampling-stations were established Water samples were drawn from subsuperficial and 3 m depth from June 1984 to October 1985, during ten cruises. The heterotrophic aerobic, marine (BM) and terrestrial (BT) bacteria counts were subjected to analysis of variance (ANOVA), which were highly significant for both sampling stations and months of the year (Table 1). Scheffe's and Student-Newman-Keul's contrast tests were used to indicate which sampling stations and months of the year resulted in significant differences in number of bacteria (Tables 2, 3). Subsuperficial and 3 m counts were analysed by the signification F test. No significant differences were detected. Very good correlations were observed between BM and BT at each level (Table 4). Bacteria behaviour characteristics would be used to detect changes produced in the estuary due to human activities.

Distribución espacial y temporal de bacterias aerobias en el estuario da Bahia Blanca, Argentina / Spatial and temporal distribution of aerobic bacteria in Bahia Blanca estuary, Argentina

Se establecieron 13 estaciones de muestreo en el estuario de Bahía Blanca con el objeto de realizar un estudo de base para conocer el estado bacteriológico actual de sus aguas. Durante el período comprendido entre junio 1984-octubre 1985 se realizaron 10 campañas para extraer muestras de agua subsuperficiales y a 3 m de profundidad. El análisis de varianza (ANOVA) realizado con el recuento de las bacterias heterótrofas aerobias, marinas (BM) y terrestres (BT), dio altamente significativo para las estaciones y para los meses del año. Mediante los contrastes de Scheffé y SNK, se determinaron las estaciones y los meses que dieron marcadas diferencias, en los recuentos bacterianos. La prueba F de significación no marcó diferencias entre los recuentos subsuperficiales y 3 m de cada grupo. Valores de correlación muy significativos se obtuvieron entre BM y BT en cada nivel. El patrón de comportamiento de las bacterias puede servir para detectar cambios, producidos en el estuario, por actividades humanas

[Bacterial fluctuations in the recreational waters of the Mar del Plata area]. / Fluctuaciones bacterianas en aguas recreacionales de la zona de Mar del Plata.

In the period comprised between 1981 and 1983, a study was carried out in relation with the bacteriological quality of the sea water used for recreational purposes. Beaches are situated along 35 km of coast, including Mar Chiquita and Gral. Pueyrredón Departments. The principal pollution focus is the city of Mar del Plata which, like many other big cities, overturns its industrial, rainy and urban sewer liquids to the sea, with no previous treatment, in most of the cases. The effluent open sewer, situated in the north suburban district, drives into the sea the content of three maximum sewers that recollect domiciliary branches. To determine quali and quantitatively heterotrophic aerobic mesophilic, psicrophilic, marine and E. coli bacteria, water samples were taken at 0.30 m depth, behind the shoal, in each of the 17 determined stations (Figure 1), and an enumeration of colonies in agar plate was carried out in duplicate. E. coli was used as indicator of fecal contamination and served to establish the quality of the water used in bath and other recreational functions. The quantification was done by recounts in plates or membrane filter methods, in duplicate, with previous revivification. Serology of strains isolated from marine medium by polyvalent sera was done. Independently of the recount obtained, the distribution of serological groups was rather uniform along all the coast. Colony-forming units (CFU) did not exceed values of 240/100 ml, except in the beach situated at 0.5 km of the effluent, which always gave values above those accepted internationally for bathing waters or other recreational uses (Figure 2).(ABSTRACT TRUNCATED AT 250 WORDS)