Impacto de la contaminación orgánica sobre el fitoplancton de un arroyo de la llanura pampeana

Abstract

RESUMEN.Este trabajo analiza la influencia de la calidad del agua sobre el fitoplancton y, en particular, sobre el ensamble de euglenofitas de un arroyo periurbano de la provincia de Buenos Aires (Argentina), muy afectado por la recepción de aguas residuales urbanas e industriales. Los índices de calidad de agua ICA (Berón 1984) calculados sobre el cauce principal y sus afluentes mostraron un deterioro marcado de las aguas y evidenciaron un claro patrón espacial. Además, en más de un sitio muestreado, muchos de los valores de los parámetros indicadores de la calidad del agua para la preservación de la vida acuática excedieron los rangos establecidos por las normas nacionales. El fitoplancton estuvo dominado por clorofitas, con codominancia de cianobacterias y euglenofitas. Se identificaron las especies de euglenofitas y se evaluó la presencia de deformaciones morfológicas, que fueron asociadas a la contaminación orgánica. Dada la importancia de las comunidades autotróficas en arroyos de llanura, se sugiere implementar el uso de los ensambles de euglenofitas como centinelas de los cambios producidos por el exceso de materia orgánica característico de los cursos urbanizados.[Palabras clave: Euglenophyta, arroyo periurbano, calidad de agua, aguas residuales industriales] A�������. Organic pollution impact on the phytoplankton of a stream of the Pampas plains. This paper analyzes the influence of water quality on phytoplankton, focusing on the euglenoid assemblages of a periurban stream in the province of Buenos Aires (Argentina), strongly impacted by urban and industrial wastewater. The ICA water quality index (Berón 1984) calculated for the main channel and its tributaries showed a marked deterioration of the waters and evidenced a clear spatial pa�ern. In addition, in some of the sampled sites, water quality indicators exceeded the ranges established by national standards. The phytoplankton was dominated by chlorophytes, with codominance of cyanobacteria and euglenophytes. Euglenophyta species were identified and the occurrence of morphological anomalies was associated and evaluated in relation with organic pollution. Given the importance of autotrophic communities in lowland streams, we suggest the use of euglenophyte assemblages as sentinels of changes produced by the excess of organic ma�er, which is characteristic of urban watercourses.

Water quality assessment of a temperate urban lagoon using physico-chemical and biological indicators

“…Our results coincided with similar works in the Pampas region influenced by urbanization [65] and the lagoon in Parque Unzué's FGs were similar to those found in Pampean streams associating the FGs P and W1 with moderate COD values and turbidity and W2 with high values of these variables [5]. Moreover and similar to this work, another study associated the phytoflagellates (mixotrophic) with high concentrations of organic matter and lixiviate pollutants [81].…”

“…Conversely, the Latin American cities have given little importance to these ecosystems in urban ecology, despite the accelerated losses of biodiversity [83]. Argentina has a significant diversity of urban lagoons and the studies carried out there have focused mainly on epidemiological aspects [27]. Therefore, the phytoplankton studies in these ecosystems are scarce [15,29,34,35,[60][61][62].…”