Optical Properties and Light Climate in Lake Verevi

Reinart, Anu; Arst, Helgi; Pierson, Donald C.

doi:10.1007/s10750-005-4142-1

Cited by 10 publications

(8 citation statements)

References 17 publications

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“…In the mainly anaerobic hypolimnetic layer the bacterial number was strongly correlated (partial r > 0.80, p < 0.01) to the concentration of total nutrients (N, P) and phosphate, but not with the inorganic nitrogen. A strong correlation was also found Shaded area on the plot shows the part of water-column below the light attenuation of 1% (z 1% ) (Reinart et al, 2005) at mid-day (12:00).…”

Section: Relationships Between Bacterioplankton With Other Biota and mentioning

confidence: 60%

Bacterioplankton Abundance and Activity in a Small Hypertrophic Stratified Lake

2005

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Bacterioplankton abundance and production were followed during one decade (1991)(1992)(1993)(1994)(1995)(1996)(1997)(1998)(1999)(2000)(2001) in the hypertrophic and steeply stratified small Lake Verevi (Estonia). The lake is generally dimictic. However, a partly meromictic status could be formed in specific meteorological conditions as occurred in springs of 2000 and 2001. The abundance of bacteria in Lake Verevi is highly variable (0.70 to 22 · 10 6 cells ml )1 ) and generally the highest in anoxic hypolimnetic water. In 2000-2001, the bacterial abundance in the hypolimnion increased probably due to meromixis. During a productive season, heterotrophic bacteria were able to consume about 10-40% of primary production in the epilimnion. Our study showed that bacterioplankton in the epilimnion was top-down controlled by predators, while in metalimnion bacteria were dependent on energy and carbon sources (bottom-up regulated). Below the thermocline hypolimnetic bacteria mineralized organic matter what led to the depletion of oxygen and created anoxic hypolimnion where rich mineral nutrient and sulphide concentrations coexisted with high bacterial numbers.

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Section: Relationships Between Bacterioplankton With Other Biota and mentioning

confidence: 60%

Bacterioplankton Abundance and Activity in a Small Hypertrophic Stratified Lake

2005

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“…Although Reinart et al (2005) observed a pronounced seasonality of the limnological features in an Estonian lake, time was not considered in the generation of models correlating k and SD. In our study, the effects of time depended on the ecosystem considered.…”

Section: Discussionmentioning

confidence: 99%

Prediction of the light attenuation coefficient through the Secchi disk depth: empirical modeling in two large Neotropical ecosystems

Padial

Thomaz

2008

Limnology

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The easiest way to evaluate water transparency is from the Secchi disk depth (SD). The behavior of radiation passing through water can also be quantified by the light attenuation coefficient (k) of photosynthetically active radiation (PAR), measured using quanta meters. Due to the high costs of quanta meters, k is usually predicted from SD. This prediction can be made using the index SD 9 k or using nonlinear models that correlate these variables. The aims of this study were to generate models predicting k through SD in two large Neotropical ecosystems (a reservoir and a floodplain) and to test whether 1.7, the index used worldwide, is adequate for predicting k in these ecosystems. The current paper also tested the effects of time (between seasons and among years) and space (between ecosystems and inside each ecosystem) upon such predictions. A standard 30-cm Secchi disk was used to measure SD. Simultaneously, PAR was measured at two depths to estimate k. A total data set of 2,136 measurements taken from 2001 to 2005 was used. The index generated, 2.26, was significantly different from 1.7 (t test, p \ 0.01). This suggests that 1.7 is not adequate for Neotropical ecosystems. In general, both the index and the models generated differed across ecosystems and over time. In addition, the analysis showed that a nonlinear model (k = 2.00 9 SD -0.76 , N = 2,136) was more reliable for predictions.

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“…This phenomenon occurred only when the water column was illuminated. According to our measurements (see also Reinart et al, 2005), in L. Verevi only 1% of light penetrates generally down to 3.5-5.5 m and our intermediate trap was placed at the depth of 5 m. Despite the great variability of incident irradiance, the exponential light extinction was in all cases very similar.…”

Section: Nutrients In the Sediment Trapsmentioning

confidence: 57%

“…Description of lake , its environmental properties and peculiar partial meromixis in 2000 and 2001 is described in different articles of present issue Reinart et al, 2005;Ko˜iv & Kangro, 2005;No˜ges & Solovjova, 2005;No˜ges, 2005).…”

Section: Methodsmentioning

confidence: 99%

Sedimentation Rate of Seston during the Formation of Temperature Stratification after Ice Break-up in the Partly Meromictic Lake Verevi

Ott¹,

Rakko²,

Sarik³

et al. 2005

Hydrobiologia

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The small strongly stratified hard-water hypertrophic lake Verevi (max. depth 11.0 m, surface area 12.6 ha, mean depth 3.6 m) was investigated in 2000 and in 2001. The lake is sheltered from winds, and the role of waves in mixing the water column is minimal. Eutrophication favours the strengthening of stratification. Early warm springs cause a fast stagnation of the water column forming partly meromictic conditions. Seston content of water and in sediment traps in 3 layers was measured several times during the formation of stratification. Besides measuring particulate matter, in 2001, the nutrient content of the trapped sediment was analysed. During the first 7 days of the investigation, 30% of the total particle sedimentation took place. The sedimentation rate of particulate matter was 0.4-6.3 g m -2 d )1 dry weight in different layers of the water column. Daily average sedimentation loss rate was 27% of the total amount of seston of the epilimnion, whilst from the meta-and hypolimnion the settling was much slower (9.6 and 7.3%, respectively). In our experiments with twin sediment traps, to one of which formaldehyde was added, the PO 43) -P concentration was 19% smaller in the trap without formaldehyde, probably due to planktonic uptake. The relationship between primary and export production is loop-like. The shape was irregular, indicating a high grazing rate of zooplankton.

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Optical Properties and Light Climate in Lake Verevi

Cited by 10 publications

References 17 publications

Bacterioplankton Abundance and Activity in a Small Hypertrophic Stratified Lake

Bacterioplankton Abundance and Activity in a Small Hypertrophic Stratified Lake

Prediction of the light attenuation coefficient through the Secchi disk depth: empirical modeling in two large Neotropical ecosystems

Sedimentation Rate of Seston during the Formation of Temperature Stratification after Ice Break-up in the Partly Meromictic Lake Verevi

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