QUANTITATIVE METHOD FOR DETERMINING A REPRESENTATIVE ALGAL SAMPLE COUNT<sup>1</sup>

Pappas, Janice L.; Stoermer, Eugene F.

doi:10.1111/j.0022-3646.1996.00693.x

Cited by 115 publications

(53 citation statements)

References 5 publications

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“…Counting efficiency followed Pappas and Stoermer (1996). Abundant and dominant species selection followed Lobo and Leighton (1986) and diatom densities (valves/cm 2 ) were based on Batarbee (1986).…”

Section: Methodsmentioning

confidence: 99%

Responses of periphytic diatoms to mechanical removal of Pistia stratiotes L. in a hypereutrophic subtropical reservoir: dynamics and tolerance

2013

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The Itaqui reservoir in Paraná state, southern Brazil, is dominated by the floating macrophyte Pistia stratiotes L. and is used for recreation and irrigation. The reservoir's excessive plant cover suggests an extreme trophic state and interferes with multiple uses. The aims of this study were to determine the trophic state of the reservoir water and to document the limnological conditions and the composition of the periphytic diatom community before and after the mechanical removal of macrophytes. As each diatom species has certain autoecological requirements in a given geographic area, another objective of the study was to identify diatoms that can be considered tolerant of the reservoir's trophic state in a substropical environment. Local water samples collected for physical and chemical analyses, including estimates of chlorophyll a, showed the hypereutrophic status of the reservoir before and after macrophyte removal. Environmental conditions exceeded acceptable values for fishing and irrigation, providing a clear example of how the inadequate management of water resources can directly reduce their usefulness. Trimestral sampling was carried out between May 2008 and February 2009. For quantitative analyses, biofilms were scrubbed off glass slides submerged for 30 days at a depth of approximately 40 cm. Diatom samples were cleaned with potassium permanganate and hydrochloric acid and mounted on permanent slides with Naphrax. All individuals found in random transects under three replicates were identified and counted up to a minimum of 600 valves. Thirteen species tolerant of eutrophication were selected. Four species mostly known from low-nutrient sites may be considered tolerant of eutrophic conditions. The composition of the diatom community was influenced by seasonal changes in temperature and rainfall. Canonical Correspondence Analyses confirmed a correlation between higher diatom densities and the increased photic zone following macrophyte removal.Keywords: Itaqui Reservoir, PR, artificial substrate, eutrophication. Respostas das diatomáceas perifíticas à remoção mecânica de Pistia stratiotes L. num reservatório subtropical hipereurófico: dinâmica e tolerância ResumoA represa Itaqui, localizada no estado do Paraná, sul do Brasil, é dominada pela macrófita flutuante Pistia stratiotes L. e utilizada para recreação e irrigação. Esta excessiva massa vegetal sugere um elevado estado de trofía e interfere nos múltiplos usos do corpo d'água. Os objetivos deste estudo foram determinar o estado trófico da represa e documentar suas condições limnológicas e a composição da comunidade de diatomáceas perifíticas antes e após a remoção mecânica da massa de macrófitas. As espécies apresentam autoecologias específicas em diferentes áreas geográficas, desta forma outro objetivo foi identificar diatomáceas em ambiente subtropical que possam ser consideradas tolerantes ao estado trófico da represa. Amostras de água foram coletadas para analises físicas e químicas, incluindo estimativas de clorofila-a que evidenciou...

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Section: Methodsmentioning

confidence: 99%

Responses of periphytic diatoms to mechanical removal of Pistia stratiotes L. in a hypereutrophic subtropical reservoir: dynamics and tolerance

2013

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“…And, if the latter, how should effort be split between spatial and temporal replicates from the same water body? Pappas & Stoermer (1996) showed that the number of taxa recorded increases as effort spent per sample increases. But does this extra information on biodiversity actually contribute to our knowledge about ecological status at a site?…”

Section: Dealing With Variabilitymentioning

confidence: 99%

Data rich, information poor? Phytobenthos assessment and the Water Framework Directive

Kelly¹

2013

European Journal of Phycology

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The Water Framework Directive (WFD) provides the legal basis for water management in the European Union (EU). Twelve years after it was passed, all but five EU Member States had phytobenthos assessment methods for rivers, whilst nine had methods for lakes. Most are based on diatoms, although a few are supplemented by evaluations of non-diatoms and some include macroalgae as part of parallel macrophyte assessments. Norway is the exception, with assessment based on non-diatom algae alone. Over half of all states have methods based wholly or partly on weighted average metrics developed before the onset of the WFD, with nine choosing the Indice de Polluosensibilité Specifique. Such metrics generally have high correlations with the predominant nutrient or organic pollution gradient and, as such, represent pragmatic solutions to ecological status assessment. However, their widespread use raises questions about what, exactly, 'ecological status' means. Strong relationships with chemical pressure gradients may be a mixed blessing as pressure gradients are often composed of several intercorrelated variables, making it difficult to disentangle correlation and causation in the absence of ecophysiological studies of individual species. Moreover, the focus on strong relationships with chemical gradients means that most phytobenthos metrics describe the scale of hazard at a site rather than the risk posed to other trophic levels and to ecosystem services. This first generation of phytobenthos assessment tools may be inadequate when catchment managers need guidance on remediation strategies for particular water bodies. A second generation of assessment tools, focused on the fitness of the phytobenthos as part of aquatic ecosystems, rather than just as indicators of chemical conditions, is needed if the goal of good ecological status around Europe is to be achieved.

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“…Os indivíduos foram identificados e contados em microscópio óptico Olympus CX31, até que um mínimo de 600 valvas fosse registrado, conforme recomendações de Kobayasi & Mayama (1982), com uma eficiência de contagem de 90% (Pappas & Stormer 1996). As espécies abundantes e dominantes foram determinadas de acordo com o critério de Lobo & Leighton (1986), que consideram abundantes aquelas espécies cujas densidades superam a densidade média da amostra e dominantes aquelas espécies cujas densidades superam 50% da densidade total da amostra.…”

Section: Methodsunclassified

Diatomáceas perifíticas abundantes em três córregos com diferentes ações antrópicas em Maringá, PR, Brasil

Moresco¹,

Tremarin²,

Ludwig³

et al. 2011

Rev. bras. Bot.

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QUANTITATIVE METHOD FOR DETERMINING A REPRESENTATIVE ALGAL SAMPLE COUNT¹

Cited by 115 publications

References 5 publications

Responses of periphytic diatoms to mechanical removal of Pistia stratiotes L. in a hypereutrophic subtropical reservoir: dynamics and tolerance

Responses of periphytic diatoms to mechanical removal of Pistia stratiotes L. in a hypereutrophic subtropical reservoir: dynamics and tolerance

Data rich, information poor? Phytobenthos assessment and the Water Framework Directive

Diatomáceas perifíticas abundantes em três córregos com diferentes ações antrópicas em Maringá, PR, Brasil

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QUANTITATIVE METHOD FOR DETERMINING A REPRESENTATIVE ALGAL SAMPLE COUNT1

Cited by 115 publications

References 5 publications

Responses of periphytic diatoms to mechanical removal of Pistia stratiotes L. in a hypereutrophic subtropical reservoir: dynamics and tolerance

Responses of periphytic diatoms to mechanical removal of Pistia stratiotes L. in a hypereutrophic subtropical reservoir: dynamics and tolerance

Data rich, information poor? Phytobenthos assessment and the Water Framework Directive

Diatomáceas perifíticas abundantes em três córregos com diferentes ações antrópicas em Maringá, PR, Brasil

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QUANTITATIVE METHOD FOR DETERMINING A REPRESENTATIVE ALGAL SAMPLE COUNT¹