Optical and biological properties of Lake Ülemiste, a water reservoir of the city of Tallinn II: Light climate in Lake Ülemiste

Reinart, Anu; Arst, Helgi; Erm, A.; Trei, Tiiu; Hussainov, Medhat

doi:10.1046/j.1440-1770.2001.00128.x

Cited by 10 publications

(7 citation statements)

References 21 publications

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“…As previously mentioned, the analysis of the underwater light climate of Lake Ülemiste (measurements conducted by 72 A. Erm et al using underwater radiation sensors and by a modelled temporal change of underwater light field) are presented in Part II of the present paper (Reinart et al 2001). The data collected for Lake Ülemiste confirm that it is an almost hypertrophic shallow lake, with a thick layer of sediments on its bottom.…”

Section: Correlative Relationships Between Bio-optical Parameters Of supporting

confidence: 60%

“…The data obtained were analysed considering the following aspects: (i) temporal and spatial variations of bio-optical parameters; (ii) comparison of the values of these parameters for Lake Ülemiste with those for other lakes; (iii) correlative relationships between parameters (Lake Ülemiste together with other lakes). The under water light field of Lake Ülemiste is described and analysed in 'Part II' of the present paper (Reinart et al 2001).…”

Section: Resultsmentioning

confidence: 99%

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Optical and biological properties of Lake Ülemiste, a water reservoir of the city of Tallinn I: Water transparency and optically active substances in the water

Erm¹,

Arst²,

Trei

et al. 2001

Lakes & Reservoirs

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Optical and biological measurements were performed in Lake Ülemiste in the summer of 1997 (four measurement days), and from May to October in 1998 (12 measurement days). This kind of data, describing the type and amount of optically active substances in the water, phytoplankton characteristics, the underwater light field, and temperature–oxygen situation in the lake are necessary when estimating the ecological state of the lake. Lake Ülemiste is the main drinking water reservoir of Tallinn, the capital of Estonia. Phytoplankton abundance and biomass, chlorophyll a and suspended matter were determined from collected Lake Ülemiste water samples in the laboratory. Spectrophotometrical processing of the filtered and unfiltered water was carried out to describe the beam attenuation coefficient spectra and optical influence of yellow substance in the water. Vertical profiles of downwelling irradiance of the PAR (400–700 m) region of the spectrum (and from these data the averaged over depth diffuse attenuation coefficient) were determined. The relative transparency of the water was estimated by using a Secchi disk. Passive optical remote measurements were episodically made from aboard a boat. Results obtained confirmed that Lake Ülemiste is turbid (almost hypertrophic), comparable with most turbid lakes in Estonia (e.g. Lake Võrtsjärv) and Finland (Lake Tuusulanjärvi). Its chlorophyll a content varied within the range 13–121 mg m–3, phytoplankton biomass 3–107 mg L–1, phytoplankton abundance 65 000–999 000 mL–1, suspended matter 8–34 mg L–1, effective concentration of the yellow substance 6–30 mg L–1, diffuse attenuation coefficient of light in the PAR region 1.0–3.3 m–1 and a Secchi disk depth of 0.5–1.75 m. The temporal variation of the spatial averages of these parameters during 1998 was analysed. Almost all characteristics showed an increase from May to midsummer with a maximum in late July or in August (correspondingly the Secchi depth values were minimal in late summer). The amount of yellow substance was an exception, which was nearly constant during the observation period. The maximum level of chlorophyll a content in July and August 1998 markedly exceeded that in 1997, despite the fact that the summer of 1997 was sunny, but the summer of 1998 was cold and rainy. The correlative relationships between the different parameters were investigated together with the respective data for other lakes. They show that the data of Lake Ülemiste supplemented the correlation graph in the region of turbid lakes, whereby in all cases the correlation coefficient increased following the addition of Lake Ülemiste data. The highest correlation coefficient was obtained when light attenuation coefficient values were correlated with a sum of weighted concentrations of chlorophyll a, yellow substance and suspended matter (multiple regression analysis).

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Section: Correlative Relationships Between Bio-optical Parameters Of supporting

confidence: 60%

Section: Resultsmentioning

confidence: 99%

Optical and biological properties of Lake Ülemiste, a water reservoir of the city of Tallinn I: Water transparency and optically active substances in the water

Erm¹,

Arst²,

Trei

et al. 2001

Lakes & Reservoirs

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“…For the sake of convenience and standardization, the depth at which 1% of surface light intensity occurs can be substituted for euphotic depth in many studies. Alternatively the depth of the underwater light intensity of 14 μmol·m −2 ·s −1 may be used [2] . Euphotic depth is mainly affected by four matters namely, pure water, chromophoric dissolved organic matter, nonalgal particulates and phytoplankton [3] .…”

Section: Environmental Significancementioning

confidence: 99%

Temporal-spatial variations of euphotic depth of typical lake regions in Lake Taihu and its ecological environmental significance

Zhang

Qin

et al. 2006

SCI CHINA SER D

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By using the data of underwater irradiance measured in the different lake regions of Lake Taihu during 1998-2004 and total suspended solids (TSS), wind speeds of the total 13 stations in typical lake regions during 1993-2003, this paper analyzes the factors of influencing on PAR (photosynthetically available radiation) attenuation, euphotic depth, and presents the temporal and spatial variations of euphotic depth of typical lake regions in Lake Taihu, and the spectral distributions of euphotic depth at station 2. The results show that the concentration of TSS is the most important factor impacting PAR attenuation, followed by chlorophyll a; chromophoric dissolved organic matter (CDOM) has little impact on the PAR euphotic depth. During 1993-2003, the mean yearly PAR euphotic depths of the typical lake regions ranged from 1.04 to 1.95 m with a mean value of 1.35±0.23 m. The PAR euphotic depth fell into 3 spatial zone types: Type I, the lowest, including the lake center and the inflows of rivers; Type II, intermediate, including Meiliang Bay, Wulihu Lake and Gonghu Bay; Type III, the greatest, including the East Lake Taihu; corresponding mean depths were approximately 1.1, 1.4, 2.0 m, respectively. The seasonal variations of euphotic depths were not quite the same in different lake regions. In the lake center, the mean values of PAR euphotic depth in summer and autumn were significantly greater than those in winter and spring; in the Meiliang Bay, winter means were significantly greater than in the other three seasons; in the East Lake Taihu, winter means were significantly less than in the other three seasons. However, no distinct seasonal change was recorded in the Wulihu Lake, Gonghu Bay and the inflows of rivers. The spectral distributions of euphotic depth present a minimal value at the blue light wave band of 400 nm, and a peak at the green light wave band of around 580 nm. In 1998 and 1999, based on the seasonal many-day continuous measurements, the PAR euphotic depths at station 2 were recorded 2.00±0.21, 2.52±0.45, 1.58±0.24, 2.00 ±0.15 m in spring, summer, autumn and winter, respectively. The peak value of 440 nm absorbed by phytoplankton corresponded to a euphotic depth of only 0.81-1.47 m (mean 1.07±0.29 m), which was much lower than the mean PAR euphotic depth of 1.98±0.41 m.

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“…Alternatively, the depth where the underwater light intensity was 14 μmol/m 2 /s was also used to define the euphotic depth (Reinart et al . ; Zhang et al . ).…”

Section: Methodsmentioning

confidence: 97%

Spatiotemporal variations in euphotic depth and their correlation with influencing factors in a tributary of the Three Gorges Reservoir

Hong

Fang

et al. 2013

Water & Environment J

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After the initial impoundment of the Three Gorges Reservoir (TGR), most of its tributaries have been influenced because of the backwater and the input of nutrients. The spatiotemporal variability in euphotic depth and its major influencing factors were investigated in the Xiaojiang River Basin of the TGR to reveal this change. Analyses were based on the photosynthetically active radiation (PAR) and water quality indices in five sampling sites of the Xiaojiang River from May 2007 to April 2009. Results showed only slight spatial variation in the average euphotic depth while significant temporal variation was taken place. Moreover, correlation analysis indicated that the diffuse attenuation coefficients for PAR (Kd(PAR)) was significantly correlated to the total suspended solids (TSS) (R 2 = 0.6794), but not to chlorophyll-a (Chl-a) (R 2 = 0.045). The unique hydrological conditions of the TGR might be the determinants of the spatiotemporal variability. bs_bs_banner Water and Environment Journal. Print

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Optical and biological properties of Lake Ülemiste, a water reservoir of the city of Tallinn II: Light climate in Lake Ülemiste

Cited by 10 publications

References 21 publications

Optical and biological properties of Lake Ülemiste, a water reservoir of the city of Tallinn I: Water transparency and optically active substances in the water

Optical and biological properties of Lake Ülemiste, a water reservoir of the city of Tallinn I: Water transparency and optically active substances in the water

Temporal-spatial variations of euphotic depth of typical lake regions in Lake Taihu and its ecological environmental significance

Spatiotemporal variations in euphotic depth and their correlation with influencing factors in a tributary of the Three Gorges Reservoir

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