Periphyton in the aquatic ecosystem and food webs.

Wetzel, R. G.; Äzim, M.E.; Verdegem, M.C.J.; Dam, A. A. van; Beveridge, M. C. M.

doi:10.1079/9780851990965.0051

Cited by 12 publications

(8 citation statements)

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“…), light is the first energy source for the autotrophic community (Hill 1996) and its quantity and quality are closely related with temporal variability of primary production in rivers (Hill and Knight 1988). Different factors can influence light quality and quantity reaching biofilms (riparian vegetation, water turbidity, biofilm thickness, etc., Hill 1996) and biofilms can colonize a wide range of benthic light environments from turbid rivers under dense canopy cover to open shallow and clear streams (Wetzel 2005). In addition, in all these environments, light quantity and quality fluctuate throughout the day due to cloudy spells or movements in the riparian vegetation among others (Hill 1996).…”

Section: Introductionmentioning

confidence: 99%

Light history modulates antioxidant and photosynthetic responses of biofilms to both natural (light) and chemical (herbicides) stressors

et al. 2012

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In multiple stress situations, the co-occurrence of environmental and chemical factors can influence organisms' ability to cope with toxicity. In this context, the influence of light adaptation on the response of freshwater biofilms to sudden light changes or to herbicides exposure was investigated by determining various parameters: diatom community composition, photosynthetic parameters, chlorophyll a content, antioxidant enzyme activities. Biofilms were grown in microcosms under sub-optimal, saturating, and high light intensities and showed already described characteristics of shade/light adaptation (community structure, photosynthetic adaptation, etc.). Light history modulated antioxidant and photosynthetic responses of biofilms to the stress caused by short-term exposure to sudden light changes or to herbicides. First biofilms adapted to sub-optimal light intensity (shade-adapted) were found to be more sensitive to an increase in light intensity than high-light adapted ones to a reduction in light intensity. Second, while light history influenced biofilms' response to glyphosate, it had little influence on biofilms' response to copper and none on its response to oxyfluorfen. Indeed glyphosate exposure led to a stronger decrease in photosynthetic efficiency of shade-adapted biofilms (EC(50) = 11.7 mg L(-1)) than of high-light adapted communities (EC(50) = 35.6 mg L(-1)). Copper exposure led to an activation of ascorbate peroxidase (APX) in biofilms adapted to sub-optimal and saturating light intensity while the protein content decreased in all biofilms exposed to copper. Oxyfluorfen toxicity was independent of light history provoking an increase in APX activity. In conclusion this study showed that both previous exposure to contaminants and physical habitat characteristics might influence community tolerance to disturbances strongly.

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Section: Introductionmentioning

confidence: 99%

Light history modulates antioxidant and photosynthetic responses of biofilms to both natural (light) and chemical (herbicides) stressors

et al. 2012

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“…Periphyton mainly consists of photosynthetic organisms (both eukaryotes and cyanobacteria) but also bacteria and fungi, can colonize any type of substratum in the photic zone, and grows imbedded within a polysaccharidic matrix (Wetzel 2001). It has been demonstrated that the contribution of periphyton to carbon fixation and nutrient cycling can be significant, particularly in lotic systems (Wetzel 2005). It can even be greater than that of phytoplankton or macrophytes in some clear shallow lakes (Liboriussen and Jeppesen 2003).…”

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confidence: 99%

STREAM PERIPHYTON PHOTOACCLIMATION RESPONSE IN FIELD CONDITIONS: EFFECT OF COMMUNITY DEVELOPMENT AND SEASONAL CHANGES¹

Laviale

Prygiel

Lemoine

et al. 2009

Journal of Phycology

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The photochemical behavior of intact stream periphyton communities in France was evaluated in response to the time course of natural light. Intact biofilms grown on glass substrata were collected at three development stages in July and November, and structural parameters of the biofilms were investigated (diatom density and taxonomy). At each season, physiological parameters based on pigment analysis (HPLC) and pulse-amplitude-modulated (PAM) chl fluorescence technique were estimated periodically during a day from dawn to zenith. Regardless of the community studied, the optimal quantum yield of PSII (Fv /Fm ), the effective PSII efficiency (ΦPSII ), the nonphotochemical quenching (NPQ), and the relative electron transport rate (rETR) exhibited clear dynamic patterns over the morning. Moreover, microalgae responded to the light increase by developing the photoprotective xanthophyll cycle. The analysis of P-I parameters and pigment profiles suggests that July communities were adapted to higher light environments in comparison with November ones, which could be partly explained by a shift in the taxonomic composition. Finally, differences between development stages were significant only in July. In particular, photoinhibition was less pronounced in mature assemblages, indicating that self-shading (in relation to algal biomass) could have influenced photosynthesis in older communities.

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“…The Gravataí river is situated in a plain region and its flow rate is low, thus increasing the flow and turbulence in the system may mean an early renewal of nutrients around the cells, favoring higher nutrient availability. Within a specific range of water turbulence and current velocity, the boundary layer thickness between the periphyton and overlying water is reduced and enhanced nutrient exchange occurs as a result (Riber & Wetzel, 1987;Wetzel, 2005).…”

Section: Discussionmentioning

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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Periphyton in the aquatic ecosystem and food webs.

Cited by 12 publications

References 0 publications

Light history modulates antioxidant and photosynthetic responses of biofilms to both natural (light) and chemical (herbicides) stressors

Light history modulates antioxidant and photosynthetic responses of biofilms to both natural (light) and chemical (herbicides) stressors

STREAM PERIPHYTON PHOTOACCLIMATION RESPONSE IN FIELD CONDITIONS: EFFECT OF COMMUNITY DEVELOPMENT AND SEASONAL CHANGES¹

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

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Periphyton in the aquatic ecosystem and food webs.

Cited by 12 publications

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Light history modulates antioxidant and photosynthetic responses of biofilms to both natural (light) and chemical (herbicides) stressors

Light history modulates antioxidant and photosynthetic responses of biofilms to both natural (light) and chemical (herbicides) stressors

STREAM PERIPHYTON PHOTOACCLIMATION RESPONSE IN FIELD CONDITIONS: EFFECT OF COMMUNITY DEVELOPMENT AND SEASONAL CHANGES1

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

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STREAM PERIPHYTON PHOTOACCLIMATION RESPONSE IN FIELD CONDITIONS: EFFECT OF COMMUNITY DEVELOPMENT AND SEASONAL CHANGES¹