Sampler collection gadget for epilithic diatoms

Salomoni, S.E; Torgan, Lezilda Carvalho

doi:10.1590/s1519-69842007000400013

Cited by 4 publications

(4 citation statements)

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“…Simultaneous to the collection of water samples, the epilithic diatoms were sampled from rock substrates (basaltic cobbles) previously suspended below the sub-surface of the river (depth of 20 cm), using polystyrene floats as supports, installed at six sampling stations along the river (Salomoni et al, 2006(Salomoni et al, , 2007. The supports and substrates were placed near the river banks, avoiding shaded spots.…”

Section: Sampling Of Epilithic Diatomsmentioning

confidence: 99%

Application of water quality biological indices using diatoms as bioindicators in the Gravataí river, RS, Brazil

et al. 2011

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The Gravataí river situated in the metropolitan region of Porto Alegre has an area of approximately 2.020 km 2 and provides public water supply to about 500,000 inhabitants in 5 municipalities (latitude 29° 45'-30° 12' S; longitude 50° 27'-51° 12' W). The river basin has two regions with distinctive characteristics of occupation: the upper course shows intensive farming and the lower course presents urban and industrial uses. In this context, the aim of this study was to evaluate the water quality in the Gravataí River (RS, Brazil) by using physical, chemical and microbiological variables, and the water quality biological indices (WQBI) formulated for southern Brazilian rivers based on epilithic diatom communities as indicators. For comparison purposes, a local WQBI, called the Gravataí WQBI, was also used where species were given new saprobic values (s) and indicative values (vi) according to their occurrence and abundance in the river, using multivariate analytical techniques. The biological samples were taken every three months at six stations along the Gravataí River between September 2000 and August 2002. The results of the physical and chemical analyses of the water indicated a pollution gradient down the river, from the headwaters to the mouth, detected mainly by considering a significant decrease in the concentration of dissolved oxygen and turbidity, as well as a significant increase in BOD 5 , total nitrogen, ortho-phosphate and thermotolerant coliforms. Comparing the results obtained, differences were found regarding the predominant pollution levels as higher in the Gravataí WQBI, although both corroborated a tendency for the contamination gradient to increase from the headwaters to the mouth. Given the local anthropic changes, it is of great importance to continue the study of diatom species tolerance to organic pollution and eutrophication in different lotic systems of the region.Keywords: epilithic diatoms, bioindicators, Water Quality Biotic Indices (WQBI), organic contamination, eutrophication. Aplicação de índices biológicos da qualidade água utilizando diatomáceas como bioindicadoras no rio Gravataí, RS, BrazilResumo O rio Gravataí situado na região metropolitana de Porto Alegre tem aproximadamente 2.020 km 2 e abastece aproximadamente 500.000 habitantes em cinco municípios (latitude 29° 45'-30° 12' S; longitude 50° 27'-51° 12' W). A bacia do rio tem duas regiões com características distintas de ocupação: o curso superior mostra atividades intensivas de agricultura, e o curso inferior apresenta usos industriais e urbanos. Neste contexto, este trabalho teve por objetivo avaliar a qualidade da água do rio Gravataí, RS, utilizando variáveis físicas, químicas e microbiológicas, e o Índice Biológico da Qualidade de Água (IBQA), formulado para rios sul-brasileiros, baseado na comunidade de diatomáceas epilíticas como indicadoras. Para fins de comparação, aplicou-se um IBQA regional denominado IBQA Gravataí, no qual houve uma nova classificação dos valores sapróbicos "s" e valores indicativos ...

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Section: Sampling Of Epilithic Diatomsmentioning

confidence: 99%

Application of water quality biological indices using diatoms as bioindicators in the Gravataí river, RS, Brazil

et al. 2011

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“…Diatoms were sampled quarterly at six stations along the river (Figure 1) using Epilithic Diatom Samplers (Salomoni et al, 2007a), from September 2000 to August 2002. The exposure time of rocks in the river was about four weeks, according to the procedures recommended by Lobo & Buselato-Toniolli (1985).…”

Section: Sampling and Analysismentioning

confidence: 99%

Seasonal and spatial variation of the epilithic diatoms: case study of an organic pollution gradient in a subtropical region of southern Brazil

Salomoni

Torgan

2017

Acta Limnol. Bras.

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Cite as: Salomoni, S.E., Rocha, O. and Torgan, L.C. Seasonal and spatial variation of the epilithic diatoms: case study of an organic pollution gradient in a subtropical region of southern Brazil. Acta Limnologica Brasiliensia, 2017, vol. 29, e1. Abstract: Aim:This study aimed to understand the seasonal variation of epilithic diatoms in the Gravataí River regarding their composition and density along the river, as well as the respective relationships with local limnological variables. Methods: The diatoms were sampled quarterly using a EDS sampler exposed for four weeks from September 2000 to August 2002. An area of 75 cm 2 was scraped off the upper surface of three submerged stones totalizing a composed sample. An aliquot of 1 ml of oxidized material was mounted on a slide for the quantitative and qualitative analysis. Results: A spacial organic contamination gradient was observed in the Gravataí river due the decrease of dissolved oxygen, and increase of BOD 5, total nitrogen and ortho-phosphate from the upper to the lower course and the predominance of eutrophic conditions during periods of higher temperature (spring and summer). The epilithic diatoms presented, in the upper stretch, a seasonal pattern in abundance with the highest densities during the fall and winter, the density enhance was associated to mild and low temperatures, lowest turbidity and nutrients availability. Bacillariaceae was dominant in the spring, Eunotiaceae and Bacillariaceae in the summer and fall and Gomphonemathaceae was strongly dominant followed by Eunotiaceae in winter. In the lower course Bacillariaceae was dominant in all seasons except on fall 2001. These changes were determined by the substitutions in the occurrence and relative abundance of some species as Achnanthidium minutissimum, Cocconeis placentula, Eunotia bilunaris, Frustulia saxonica, Gomphonema parvulum, Nitzchia palea and Sellaphora seminulum. Conclusions: The seasonality of the diatoms was well evidenced in upper stretch of the river, therefore in the lower course with greater anthropogenic impact, fewer changes occurs in the number of species present and/or of substitution of some species by others, showing that the seasonality of the diatoms can be affected by organic contamination and eutrophication.

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“…Ecological studies on producer communities associated with artificial substrates in lotic environments are common in the literature (Biggs, 1988;Clifford et al, 1992;Fernandes and Esteves, 2003;Lobo et al, 2004;Barbee, 2005;Salomoni et al, 2007;Canani et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

A new method to quantify macroalgae and a practical sampler for experimentation in lotic habitats

2012

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Experimental studies in rivers and streams are extremely difficult to run due to the fact that the conditions of these environments are very complex and provide a high level of heterogeneity, which hinders the precise control and standardization of variables. In this study, we present a practical sampler that was designed to make it easier to conduct research projects involving benthic communities of lotic environments, as well as a new nondestructive technique for quantification of the macroalgal communities typically found in these habitats. The sampler consists of an acrylic square tube in which water flows normally inside. This structure carries a removable glass plaque with a known area and can simulate various ecological situations by changing both biotic and abiotic conditions. Thus, it can mitigate the differences between environmental characteristics where each sampler is exposed. The new technique involves capturing digital images that can monitor a unique macroalgal community in development throughout time and a more precise quantification when compared with other techniques that are widely applied. The sampler is easy to build and the images simple to quantify, allowing the detection of spatial and temporal variations in richness and abundance of investigated communities.Keywords: artificial substrate, sampling method, stream macroalgae, limnology.Um novo método para quantificar macroalgas e um prático amostrador para experimentação em ecossistemas lóticos ResumoOs estudos experimentais em rios e riachos são extremamente difíceis de serem executados, visto que as condições desses ambientes são muito complexas e proporcionam um alto nível de heterogeneidade, o que dificulta o controle e a padronização precisa das variáveis. Nesse contexto, um prático amostrador foi desenvolvido para facilitar a execução de projetos de pesquisas envolvendo comunidades bentônicas de ambientes lóticos, além de constituir uma nova técnica não destrutiva para quantificação das macroalgas tipicamente encontradas nesses habitats. O amostrador consiste de um tubo de acrílico de seção quadrada, pelo qual a água corrente flui normalmente em seu interior. Tal estrutura porta uma placa de vidro removível com área conhecida e permite simular diversas situações ecológicas, variando tanto as condições abióticas como as bióticas, além de amenizar as diferenças entre as características ambientais a que está submetido cada um dos amostradores. Diversamente, a nova técnica consiste na captura de imagens digitais que permitem o acompanhamento temporal de uma mesma comunidade de macroalgas em desenvolvimento e uma quantificação mais precisa quando comparada com técnicas amplamente aplicadas na área. O amostrador é fácil de construir e as imagens são simples para quantificar, permitindo a detecção de variações espaço-temporais na riqueza e abundância das comunidades investigadas.Palavras-chave: substratos artificiais, método de amostragem, macroalgas de riachos, limnologia.

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Sampler collection gadget for epilithic diatoms

Cited by 4 publications

References 6 publications

Application of water quality biological indices using diatoms as bioindicators in the Gravataí river, RS, Brazil

Application of water quality biological indices using diatoms as bioindicators in the Gravataí river, RS, Brazil

Seasonal and spatial variation of the epilithic diatoms: case study of an organic pollution gradient in a subtropical region of southern Brazil

A new method to quantify macroalgae and a practical sampler for experimentation in lotic habitats

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