ABSTRACT
This work present a new gadget for sampling epilithic diatoms from both lentic and lotic enviroments. The sampler consists of a polystyrene cylinder, left to float on the surface of the water, to which stone substrates are attached. This epilithic diatom sampler (EDS) can be used to detect spatial and temporal richness and density variation in the study of the diatom community, as well as in water quality monitoring.
Apresenta-se um novo dispositivo para amostragem de diatomáceas epilíticas a ser empregado em ambientes lênticos e lóticos. O amostrador é constituído por cilindro de polietileno flutuante na superfície da água onde são fixados substratos rochosos. Este amostrador de diatomáceas epilíticas (EDS) pode ser usado tanto para detectar variações espaciais e temporais de riqueza e densidade da comunidade de diatomáceas como para o monitoramento da qualidade da água.
Subject(s)
Diatoms , Environmental Monitoring/instrumentation , Fresh Water , Population Density , Population DynamicsABSTRACT
Associations of diatom species were identified, in the Arroio Sampaio Basin, Rio Grande do Sul, Brazil, based on monthly samplings over a year along Arroio Sampaio and its main tributaries, using polyamide thread as an artificial substrate. The species groupings showed four different environments: medium-lower course of Arroio Sampaio; and lower course of Arroio Teresinha; upper course of Arroio Sampaio; and lower course of Arroio Duvidosa. Among the physical and chemical variables measured, water pollution, particularly organic contamination and eutrophication, measured from BOD5 and total phosphate concentration, respectively, appeared to be one of the most important environmental factors determining the composition and structure of species associations in the area studied