Phosphorus fractions in sediments and their relevance for historical lake eutrophication in the Ponte Tresa basin (Lake Lugano, Switzerland) since 1959

Tu, Luyao; Jarosch, K; Schneider, Tobias; Grosjean, Martín

doi:10.1016/j.scitotenv.2019.06.243

Cited by 78 publications

(23 citation statements)

References 68 publications

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“…Switzerland has achieved great success in reducing phosphorus loads (Brunner et al 2019 ). The phosphorus concentrations in Swiss lakes have steadily declined since the 1980s (Rodríguez-Murillo et al 2015 ) and the current state of Swiss lakes can be generally described as good (Tu et al 2019 ). Unfortunately, due to the soil enrichment in phosphorus compounds on agricultural lands of high livestock density within the lake catchment areas, a further water quality improvement cannot be guaranteed for all lakes (Bucheli et al 2010 ; Ferré et al 2019 ).…”

Section: Methodsmentioning

confidence: 99%

An Analytical Review of Different Approaches to Wastewater Discharge Standards with Particular Emphasis on Nutrients

Preisner

Neverova-Dziopak

Kowalewski

2020

Environmental Management

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Despite the implementation of strict legal standards concerning nutrient loads within wastewater discharges in all European Union (EU) Member States it was not possible to achieve good ecological and chemical water status by 2015 in all EU countries. The main reasons for this situation are the imperfections of the legislation tools regarding the standardization of wastewater quality and the methodology of determining the conditions for wastewater introduction into receivers. The study aims to review and analyze the currently existing in various countries legal regulations setting the standards for wastewater discharged into receivers, which were intended for surface water protection and eutrophication mitigation. Besides the EU effluent standards, the regional and national regulations in chosen EU Member States (e.g., Germany, Sweden, and Denmark) have been reviewed. Moreover, the Helsinki Commission recommendations for signatory countries within the Baltic Sea catchment and the approaches for wastewater quality standardization in non-EU countries (e.g., Russia, Belarus, Switzerland, China, USA, Canada, and Dubai) were assessed. The analysis of the reviewed legal regulations allowed to diversify the methodological approaches for setting effluent quality standards in different regions and countries and to assess the effectiveness of existing legal tools in the field of eutrophication mitigation with the consideration of the environmental and economic reasonability. The results suggest that the receiver-oriented policies used among others in Switzerland and China are the most reasonable in terms of eutrophication mitigation.

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Section: Methodsmentioning

confidence: 99%

An Analytical Review of Different Approaches to Wastewater Discharge Standards with Particular Emphasis on Nutrients

Preisner

Neverova-Dziopak

Kowalewski

2020

Environmental Management

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“…Data availability. The data are available at PANGAEA at https://doi.org/10.1594/PANGAEA.908896 (Tu et al, 2019b).…”

Section: Resultsmentioning

confidence: 99%

The influences of historic lake trophy and mixing regime changes on long-term phosphorus fraction retention in sediments of deep eutrophic lakes: a case study from Lake Burgäschi, Switzerland

Zander

Szidat

et al. 2020

Biogeosciences

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Abstract. Hypolimnetic anoxia in eutrophic lakes can delay lake recovery to lower trophic states via the release of sediment phosphorus (P) to surface waters on short timescales in shallow lakes. However, the long-term effects of hypolimnetic redox conditions and trophic state on sedimentary P fraction retention in deep lakes are not clear yet. Hypolimnetic withdrawal of P-rich water is predicted to diminish sedimentary P and seasonal P recycling from the lake hypolimnion. Nevertheless, there is a lack of evidence from well-dated sediment cores, in particular from deep lakes, about the long-term impact of hypolimnetic withdrawal on sedimentary P retention. In this study, long-term sedimentary P fraction data since the early 1900s from Lake Burgäschi provide information on benthic P retention under the influence of increasing lake primary productivity (sedimentary green-pigment proxy), variable hypolimnion oxygenation regimes (Fe∕Mn ratio proxy), and hypolimnetic withdrawal since 1977. Results show that before hypolimnetic withdrawal (during the early 1900s to 1977), the redox-sensitive Fe∕Mn-P fraction comprised ∼50 % of total P (TP) in the sediment profile. Meanwhile, long-term retention of total P and labile P fractions in sediments was predominantly affected by past hypolimnetic redox conditions, and P retention increased in sedimentary Fe- and Mn-enriched layers when the sediment-overlaying water was seasonally oxic. However, from 1977 to 2017, due to eutrophication-induced persistent anoxic conditions in the hypolimnion and to hypolimnetic water withdrawal increasing the P export out of the lake, net burial rates of total and labile P fractions decreased considerably in surface sediments. By contrast, refractory Ca–P fraction retention was primarily related to lake primary production. Due to lake restoration since 1977, the Ca–P fraction became the primary P fraction in sediments (representing ∼39 % of total P), indicating a lower P bioavailability of surface sediments. Our study implies that in seasonally stratified eutrophic deep lakes (like Lake Burgäschi), hypolimnetic withdrawal can effectively reduce P retention in sediments and potential for sediment P release (internal P loads). However, after more than 40 years of hypolimnetic syphoning, the lake trophic state has not improved nor has lake productivity decreased. Furthermore, this restoration has not enhanced water column mixing and oxygenation in hypolimnetic waters. The findings of this study are relevant regarding the management of deep eutrophic lakes with mixing regimes typical for temperate zones.

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“…The P-fractionation extraction protocol principally follows the four-step extraction protocol in Tu et al, (2019). In addition, we added the last extraction step from Lukkari et al (2007) to determine refractory organic P (F5).…”

Section: Phosphorus Fractionation Scheme and Bulk Elements Analysesmentioning

confidence: 99%

“…This P fraction (F5) is practically biologically unavailable and subject to permanent P burial. The first four fractions are NaCl-TP (F1: loosely bound P), NaBD-TP (F2: redox-sensitive Fe-and Mn-bound P), NaOH-TP (F3: Al-and Fe-bound P), and HCl-TP (F4: Ca-bound P) (Tu et al, 2019), whereby NaCl-TP, NaBD-TP and NaOH-TP fractions together as considered relatively labile P fractions because they may release P back to the water column under anoxic or high pH environments (Rydin, 2000). The HCl-TP and refractory organic P (Ref.…”

Section: Phosphorus Fractionation Scheme and Bulk Elements Analysesmentioning

confidence: 99%

The influences of historic lake trophy and mixing regime changes on long-term phosphorus fractions retention in sediments of deep, eutrophic lakes: a case study from Lake Burgäschi, Switzerland

Tu¹,

Zander²,

Szidat³

et al. 2019

Preprint

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Abstract. Hypolimnetic anoxia in eutrophic lakes can delay lake recovery to lower trophic states via the release of sediment phosphorus (P) to surface waters on short time scales. However, the effects of hypolimnetic redox conditions and eutrophication on long-term sediment P-fraction retention are not clear yet. In this study, we investigated the sediment profiles since the early 1900s from Lake Burg&#228;schi, a deep, eutrophic lake on the Swiss Plateau. The changes of sediment P-fraction retention were assessed with respect to lake trophic evolution (sedimentary green-pigments proxy), hypolimnetic oxygenation regime (Fe&#8201;/&#8201;Mn ratio proxy), sediment geochemical characteristics, and lake restoration history. Results showed that long-term retention of total P and labile P-fractions in sediments was predominantly affected by autochthonous Fe and Mn preserved in anoxic sediments, which were controlled by past hypolimnetic redox conditions. By contrast, refractory HCl-P (Ca-P) fraction retention largely resulted from authigenic CaCO3-P precipitation and increased with higher eutrophic levels. The retention of total P and labile P fractions was considerably reduced in surface sediments from 1977&#8211;2017 when Lake Burg&#228;schi had the highest eutrophic levels and a persistent anoxic hypolimnion. We attributed the phenomenon to reduced sediment P-binding capacity (Mn and Fe oxyhydroxides) under the eutrophication-induced anoxic hypolimnion and decreased water-P concentrations due to hypolimnetic withdrawal. Our study implies that in seasonally stratified deep lakes like Lake Burg&#228;schi, hypolimnetic withdrawal of P-enriched water can effectively reduce P retention in sediments and potentials of sediment-P release (seen from low P availability after 1977). However, the restoration has not improved lake trophic state, similarly to the findings from lake limnological survey.

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Phosphorus fractions in sediments and their relevance for historical lake eutrophication in the Ponte Tresa basin (Lake Lugano, Switzerland) since 1959

Cited by 78 publications

References 68 publications

An Analytical Review of Different Approaches to Wastewater Discharge Standards with Particular Emphasis on Nutrients

An Analytical Review of Different Approaches to Wastewater Discharge Standards with Particular Emphasis on Nutrients

The influences of historic lake trophy and mixing regime changes on long-term phosphorus fraction retention in sediments of deep eutrophic lakes: a case study from Lake Burgäschi, Switzerland

The influences of historic lake trophy and mixing regime changes on long-term phosphorus fractions retention in sediments of deep, eutrophic lakes: a case study from Lake Burgäschi, Switzerland

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