Photosynthesis and Production of Epilithic Algal Communities in Thingvallavatn

Jónsson, Gunnar St.

doi:10.2307/3545053

Cited by 27 publications

(13 citation statements)

References 23 publications

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“…Stevenson & Stoermer, 1981;Kingston et al, 1983;Hoagland & Peterson, 1990). Irradiance was found by Jo´nsson (1992) to be a much more important variable than temperature, biomass and, probably, nutrients in determining epilithic assemblage photosynthesis. Hawes & Smith (1994) explained decreasing epilithic periphyton biomass with depth as an effect of changes in radiation.…”

Section: Discussionmentioning

confidence: 99%

“…Vertical zonation of epilithic diatoms has been studied in some large oligotrophic lakes, for example: Lake Michigan, USA (Kingston et al, 1983), Thingvallavatn, Iceland (Jo´nsson, 1992), Taupo, New Zealand (Hawes & Smith, 1994) and Baikal, Russia (Flower et al, 2004). The most influential environmental factors reported in diatom depthdistribution studies are light and disturbance by waves (Stevenson & Stoermer, 1981).…”

Section: Introductionmentioning

confidence: 99%

“…The most influential environmental factors reported in diatom depthdistribution studies are light and disturbance by waves (Stevenson & Stoermer, 1981). Jo´nsson (1992) argued that nutrients and water temperature can also play a minor role.…”

Section: Introductionmentioning

confidence: 99%

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Environmental controls of epilithic diatom depth-distribution in an oligotrophic lake characterized by marked water-level fluctuations

Cantonati

Scola

Angeli

et al. 2009

European Journal of Phycology

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The depth-distribution of epilithic diatoms in a carbonate meromictic lake (south-eastern Alps), characterized by marked water-level fluctuations, was investigated. Fixed stations were placed along a depth-profile at intervals of 2-3 m and sampled throughout the year using scuba diving. Diatom analysis included quantification of living cells (biovolume calculations) and the estimation of fucoxanthin concentration, which, coupled with the analysis of digested material, permitted taxonomic determination at specific or subspecific level. Multivariate analyses indicated the following variables to be significant: water-level fluctuations, photosynthetically active radiation, silica and nitrates. Diatoms had distinct depth-distributions. Quantification of densities, biovolumes and Chl a, and physiological (senescence index, fucoxanthin), functional (photosynthetic efficiency), and community structure (diversity) parameters allowed the definition of three depth-distribution zones (shallow, mid-depth and deep). The different diatom communities in these zones were confirmed by ANOSIM (analysis of similarity). The shallow, mid-depth, and deep zone were characterized by disturbance due to water-level fluctuations, high stability with favourable growth conditions and severe light limitation, respectively. Community composition and diversity depth-distribution features remained relatively stable throughout the year, while marked changes in benthic diatom biovolumes were modulated by competition for light with phytoplankton. Fucoxanthin was strongly correlated with epilithic diatom biovolumes. The results indicate that depth-distribution patterns should be considered when performing lake diatom biodiversity inventories and integrity evaluations because water-level fluctuations are likely to increase in many lakes due to increased withdrawal of water and climate change in the future.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Environmental controls of epilithic diatom depth-distribution in an oligotrophic lake characterized by marked water-level fluctuations

Cantonati

Scola

Angeli

et al. 2009

European Journal of Phycology

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“…Many similar taxa (e.g., Diploneis ovalis, Nitzschia sigmoidea, Synedra ulna, Tabellaria fl occulosa) were also identifi ed in the epilithic algal communities from the stony littoral zone (0-10 m depth) in Lake Thingvallavatn, a large deep valley lake located in southwest Iceland (Jónsson 1992). In Lake Thingvallavatn, estimated net epilithic production was high (188 g C m -2 yr -1 ) in comparison to other oligotrophic systems, with diatoms contributing approximately 50 % of the productivity (95 g C m -2 yr -1 ) of the epilithic community from 0 to 18 m depth (Jónsson 1992). Together with the predominance of relatively large pennate diatoms in the assemblages from most of the deeper oligotrophic Icelandic lakes in this study, this suggests that the contribution of the epilithic diatom community may be especially important to the productivity of deep oligotrophic Icelandic lakes.…”

Section: Relationships Between Diatoms and Measured Environmental Varmentioning

confidence: 99%

“…Notably, Foged (1974) published an extensive taxonomic treatise of mainly freshwater epipelic, epilithic and epiphytic diatom fl ora collected in 1954 from 170 localities in Iceland. More recently, Jónsson (1992) provided a detailed account of the community structure and metabolism of epilithic diatoms from Thingvallavatn, a large, oligotrophic lake in southwest Iceland.…”

Section: Introductionmentioning

confidence: 99%

Relationships between freshwater sedimentary diatoms and environmental variables in Subarctic Icelandic lakes

Karst-Riddoch¹,

Malmquist²,

Smol³

2009

fal

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Abstract:The distribution patterns of surface sediment diatom assemblages from 49 lakes were used to explore the relationship between limnological variables and diatom assemblages as well as to assess an ecological classifi cation system as a tool for the management and conservation of Icelandic freshwaters. Lakes were limnologically diverse ranging from deep, oligotrophic, ionically dilute lakes, to shallow lakes with a wide range of nutrient and ionic contents. Physical conditions (depth, surface area, surface water temperature) and nutrient and ion concentrations differed signifi cantly among ecological lake categories (i.e., plateau, spring-fed, direct-runoff, valley, glacial, and coastal lakes) (ANOVA, p < 0.05). Diatom assemblages were taxonomically diverse (329 taxa) with strong representation of planktonic, benthic and periphytic forms. Small benthic Fragilaria sensu lato (19 species and varieties) were the most abundant with combined abundances > 20 % in all but 4 of the lakes, most likely due to the generally cold lake water conditions in this subarctic region. Variation in diatom distributions was best explained by the combination of mean depth (infl uencing littoral versus planktonic habitats), surface water temperature, specifi c conductivity, alkalinity, total organic carbon, total nitrogen and SiO 2 in a canonical correspondence analysis (CCA). However, these variables did not explain distribution patterns amongst small benthic Fragilaria taxa, although some weak relationships between some taxa and these variables were evident. Distinct diatom assemblages and limnological properties among ecological lake categories support the classifi cation of Icelandic freshwaters based on major topographic, geological and hydrological characteristics. More detailed inclusion of lake depth along with lake basin form, as well as more refi ned categories of lake water origin and topographical positioning to better approximate regional climatic conditions, may improve the ecological classifi cation of Icelandic freshwaters for conservation and management practices.

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Substratum‐associated microbiota

Tuchman¹,

Peterson²

1993

Water Environment Research

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Photosynthesis and Production of Epilithic Algal Communities in Thingvallavatn

Cited by 27 publications

References 23 publications

Environmental controls of epilithic diatom depth-distribution in an oligotrophic lake characterized by marked water-level fluctuations

Environmental controls of epilithic diatom depth-distribution in an oligotrophic lake characterized by marked water-level fluctuations

Relationships between freshwater sedimentary diatoms and environmental variables in Subarctic Icelandic lakes

Substratum‐associated microbiota

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