Negligible effect of hypolimnetic oxygenation on the trophic state of Lake Jyväsjärvi, Finland

Kuha, Jonna; Palomäki, Arja; Keskinen, J.

doi:10.1016/j.limno.2016.02.001

Cited by 24 publications

(16 citation statements)

References 29 publications

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“…Our results can partially explain the earlier ineffective attempts to mitigate eutrophic conditions by long-term mixing aeration e.g. in Lake Jyväsjärvi (Kuha et al, 2016) as well as provide evidence why the total internal P loading in Lake Tuusulanjärvi (load estimates were based on a modelling approach) has remained at the same level during 20 years of aeration (Horppila et al, 2017).…”

Section: Aeration-induced Increases In Sedimentation Ratesmentioning

confidence: 56%

“…In addition to higher temperature (Rose, 1967;Jones, 1976), the aeration-induced increase in turbulence may enhance the degradation of organic material in the water column by increasing the settling time of particles (Ashley, 1983;Gantzer et al, 2009;Niemistö et al, 2016). Mixing aeration affects temperature (Salmi et al, 2014;Holmroos et al, 2016;Kuha et al, 2016) and additionally increases turbulence in the hypolimnion at least 200 m from the aerator (Niemistö et al, 2016). Despite the significant effect of aeration on the trap material in 2011, no difference in the quality of settling material in near-bottom traps of the deep areas between 2009 and 2016 was detected.…”

Section: Aeration-induced Increases In Sedimentation Ratesmentioning

confidence: 99%

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Effects of hypolimnetic aeration on the quantity and quality of settling material in a eutrophied dimictic lake

2019

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Effects of hypolimnetic aeration (pumping of epilimnetic water into the hypolimnion) on the quantity of settling material in eutrophied Lake Vesijärvi, Finland were studied by comparing spatially comprehensive gross sedimentation rates as dry and organic matter prior to aeration activity and during two aerated years. Possible changes in the organic matter (as loss on ignition, LOI), carbon (C) and nitrogen (N) contents and changes in the C/N ratio of the settling material and surface sediment were quantified. Thermal stratification broke up earlier due to aeration and was followed by sedimentation peaks. The absolute amount of dry and organic matter as well as C and N settling to the lake bottom were significantly higher in the aerated years. Increased sedimentation rates were especially pronounced in the deep zones indicating enhanced sediment focusing. Increased sedimentation of C and N reflected higher primary production during the aerated years, which most likely was associated with increased temperature and turbulence and the subsequent regeneration and recycling of nutrients in the water body. Aeration seemed to slightly enhance degradation, but contrary to its ultimate aim, it failed to decrease the phosphorus content of the water column and deposits of organic material in the deep zones of the lake.

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Section: Aeration-induced Increases In Sedimentation Ratesmentioning

confidence: 56%

Section: Aeration-induced Increases In Sedimentation Ratesmentioning

confidence: 99%

Effects of hypolimnetic aeration on the quantity and quality of settling material in a eutrophied dimictic lake

2019

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“…The fact that hypolimnion aeration does not always affect the trophic state of a lake has been confirmed by many authors [20,21,33,39,45,46] This was additionally confirmed by the experiment conducted in Lake Jyväsjärvi, where hypolimnion aeration was ceased, and which, in turn, had an extremely negative impact on the oxygen conditions in the hypolimnion, but showed no significant effect on the trophic state of the lake [20]. The results of multiannual studies on the efficiency of lake aeration seem to call into question the paradigm that oxygen controls the release of phosphorus from sediments [47,48].…”

Section: Discussionmentioning

confidence: 78%

“…In aeration methods involving thermal destratification, compressed air is introduced to the waters above the bottom, at the deepest point of the lake, which results in induced rise of the water to the surface and, consequently, mixing of the water mass [15,17,18]. The hypolimnetic oxygenation method is used in deep lakes with thermal stratification [16,[19][20][21][22]. It can be carried out using pneumatic aerators by means of injecting air or pure oxygen into hypolimnion water in a confined space and returning the oxygen-rich water to the lower layer of the lake.…”

Section: Introductionmentioning

confidence: 99%

Trophic State and Oxygen Conditions of Waters Aerated with Pulverising Aerator: The Results from Seven Lakes in Poland

Siwek

Włodarczyk

Czerniawski

2018

Water

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Eutrophic lakes of all types are marked by oxygen shortage in the bottom waters during the summer season, which results in excessive release of phosphorus load. Therefore, numerous restoration activities (chemical precipitation, aeration) are being taken based on bottom-up control, which consists of limiting the nutrient pool available to lower trophic levels. The present study provides an efficiency analysis of pulverising aeration of waters in two stratified and five unstratified lakes located in Poland. The assessment was based on monitoring data (dissolved oxygen concentration (DO), % oxygen saturation (DO%), visibility of the Secchi disc (ZSD), the concentrations of: chlorophyll a (CHL), total phosphorus (TP) and total nitrogen (TN)) obtained before and after installation of the aerator on the lakes. The study was conducted during the spring and the summer seasons. Throughout the study period, the stratified lakes exhibited oxygen saturation <0.1%. Having completed the restoration activities, TN:TP ratio was found to gradually increase in all analysed lakes, which indicates that aeration may decrease phosphate content in the water column. In three lakes, the ratio was >17, so phosphorus became the most growth-limiting nutrient. The restoration activities on four unstratified lakes had no significant effect on the changes of the Carlson trophic state indices (TSI). Either individual values of the TSI(TP), TSI(CHL) and TSI(ZSD) were comparable, or the value of TSI(TP) was higher than one or both of the remaining indices for all of the lakes.

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“…This is of crucial importance for lake ecosystems, where P is one of the most important factors regulating ecosystem productivity and sediment has a large storage of P compared to the water column (Wetzel 2001). Due to the effect of anoxia on internal P loading, artificial aeration or oxygenation (for simplicity, the term aeration is used hereafter) is frequently used in the management of eutrophicated lakes and reservoirs suffering from oxygen deficits (Cooke et al 2005;Kuha et al 2016;Grochowska et al 2017;Horppila et al 2017). However, evidence on the long-term positive effects of aeration on water and sediment quality is obscure (Gächter and Wehrli 1998;Liboriussen et al 2009;Kuha et al 2016;Horppila et al 2017).…”

Section: Introductionmentioning

confidence: 99%

3D-modelling of the thermal circumstances of a lake under artificial aeration

et al. 2017

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A 3D-model was developed to study the effects of hypolimnetic aeration on the temperature profile of a thermally stratified Lake Vesijärvi (southern Finland). Aeration was conducted by pumping epilimnetic water through the thermocline to the hypolimnion without breaking the thermal stratification. The model used time transient equation based on Navier-Stokes equation. The model was fitted to the vertical temperature distribution and environmental parameters (wind, air temperature, and solar radiation) before the onset of aeration, and the model was used to predict the vertical temperature distribution 3 and 15 days after the onset of aeration (1 August and 22 August). The difference between the modelled and observed temperature was on average 0.6°C. The average percentage model error was 4.0% on 1 August and 3.7% on 22 August. In the epilimnion, model accuracy depended on the difference between the observed temperature and boundary conditions. In the hypolimnion, the model residual decreased with increasing depth. On 1 August, the model predicted a homogenous temperature profile in the hypolimnion, while the observed temperature decreased moderately from the thermocline to the bottom. This was because the effect of sediment was not included in the model. On 22 August, the modelled and observed temperatures near the bottom were identical demonstrating that the heat transfer by the aerator masked the effect of sediment and that exclusion of sediment heat from the model does not cause considerable error unless very short-term effects of aeration are studied. In all, the model successfully described the effects of the aerator on the lake's temperature profile. The results confirmed the validity of the applied computational fluid dynamic in artificial aeration; based on the simulated results, the effect of aeration can be predicted.

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Negligible effect of hypolimnetic oxygenation on the trophic state of Lake Jyväsjärvi, Finland

Cited by 24 publications

References 29 publications

Effects of hypolimnetic aeration on the quantity and quality of settling material in a eutrophied dimictic lake

Effects of hypolimnetic aeration on the quantity and quality of settling material in a eutrophied dimictic lake

Trophic State and Oxygen Conditions of Waters Aerated with Pulverising Aerator: The Results from Seven Lakes in Poland

3D-modelling of the thermal circumstances of a lake under artificial aeration

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