Abstract

Mankind is taking advantage of numerous services by small shallow lakes such as drinking water supply, irrigation, transportation, recreational function and aesthetic values; however, eutrophication drives many of them to a deteriorated state. Internal loading of phosphorus (P) may often be the main reason why shallow lakes are unresponsive to watershed nutrient management programs. In this case, removal of sediments enriched in P is a possible method to reduce the internal P loading.
In our study, we examined the changes in sediment P mobility and internal phosphorus loading after excavation of a 1-ha highly eutrophicated lake in Viljandi, Estonia. For that, we measured redox potential of the surficial sediments, sediment pore water P concentrations and calculated diffusive fluxes in deepest location before excavation in 2015 and in three locations (close to the inflow, close the outflow, and in the center of the lake) after excavation in 2017. Additionally, total phosphorus (TP), iron (Fe), and fractions of P were determined from the sediments before and after excavation.
The P fractionation analyses revealed an increase in P retention capacity after lake excavation, indicated by an increase in Fe/P ratio of the sediments. Moreover, we observed a decrease in the concentrations of potentially mobile forms of P, as labile-P and Fe-bound P at all sampling sites. However, we observed notable spatial differences. At the station that displayed the highest Fe/P ratio, the redox potential of the surficial sediments was highest and the pore water SRP concentrations had lowest value. The diffusive fluxes were found to be highest at a sampling site that displayed anoxia in the near-bottom water layer. The lake will be monitored also in 2018 for the changes in P mobility and water quality.
Original languageEnglish
Publication statusPublished - 4 Jun 2018
MoE publication typeNot Eligible
EventLahtiLakes 2018 - Restoration of Eutrophic Lakes: Current Practices and Future Challenges -
Duration: 4 Jun 20186 Jun 2018

Conference

ConferenceLahtiLakes 2018 - Restoration of Eutrophic Lakes: Current Practices and Future Challenges
Period04/06/201806/06/2018

Fields of Science

  • 4111 Agronomy
  • Eutrophication
  • Lake restoration
  • Phosphorus retention
  • Sediment removal

Cite this

Kiani, M., Tammeorg, O., Tammeorg, P., Niemistö, J. P., Horppila, J. A., & Simojoki, A. J. (2018). Sediment internal phosphorus loading before and after excavation of a shallow lake. Poster session presented at LahtiLakes 2018 - Restoration of Eutrophic Lakes: Current Practices and Future Challenges, .
@conference{5f26908a0af142358b9885cb4be286ec,
title = "Sediment internal phosphorus loading before and after excavation of a shallow lake",
abstract = "Mankind is taking advantage of numerous services by small shallow lakes such as drinking water supply, irrigation, transportation, recreational function and aesthetic values; however, eutrophication drives many of them to a deteriorated state. Internal loading of phosphorus (P) may often be the main reason why shallow lakes are unresponsive to watershed nutrient management programs. In this case, removal of sediments enriched in P is a possible method to reduce the internal P loading.In our study, we examined the changes in sediment P mobility and internal phosphorus loading after excavation of a 1-ha highly eutrophicated lake in Viljandi, Estonia. For that, we measured redox potential of the surficial sediments, sediment pore water P concentrations and calculated diffusive fluxes in deepest location before excavation in 2015 and in three locations (close to the inflow, close the outflow, and in the center of the lake) after excavation in 2017. Additionally, total phosphorus (TP), iron (Fe), and fractions of P were determined from the sediments before and after excavation.The P fractionation analyses revealed an increase in P retention capacity after lake excavation, indicated by an increase in Fe/P ratio of the sediments. Moreover, we observed a decrease in the concentrations of potentially mobile forms of P, as labile-P and Fe-bound P at all sampling sites. However, we observed notable spatial differences. At the station that displayed the highest Fe/P ratio, the redox potential of the surficial sediments was highest and the pore water SRP concentrations had lowest value. The diffusive fluxes were found to be highest at a sampling site that displayed anoxia in the near-bottom water layer. The lake will be monitored also in 2018 for the changes in P mobility and water quality.",
keywords = "4111 Agronomy, Eutrophication, Lake restoration, Phosphorus retention, Sediment removal",
author = "Mina Kiani and Olga Tammeorg and Priit Tammeorg and Niemist{\"o}, {Juha Petteri} and Horppila, {Jukka Antero} and Simojoki, {Asko Juhani}",
year = "2018",
month = "6",
day = "4",
language = "English",
note = "LahtiLakes 2018 - Restoration of Eutrophic Lakes: Current Practices and Future Challenges ; Conference date: 04-06-2018 Through 06-06-2018",

}

Kiani, M, Tammeorg, O, Tammeorg, P, Niemistö, JP, Horppila, JA & Simojoki, AJ 2018, 'Sediment internal phosphorus loading before and after excavation of a shallow lake' LahtiLakes 2018 - Restoration of Eutrophic Lakes: Current Practices and Future Challenges, 04/06/2018 - 06/06/2018, .

Sediment internal phosphorus loading before and after excavation of a shallow lake. / Kiani, Mina; Tammeorg, Olga; Tammeorg, Priit; Niemistö, Juha Petteri; Horppila, Jukka Antero; Simojoki, Asko Juhani.

2018. Poster session presented at LahtiLakes 2018 - Restoration of Eutrophic Lakes: Current Practices and Future Challenges, .

Research output: Conference materialsPosterResearchpeer-review

TY - CONF

T1 - Sediment internal phosphorus loading before and after excavation of a shallow lake

AU - Kiani, Mina

AU - Tammeorg, Olga

AU - Tammeorg, Priit

AU - Niemistö, Juha Petteri

AU - Horppila, Jukka Antero

AU - Simojoki, Asko Juhani

PY - 2018/6/4

Y1 - 2018/6/4

N2 - Mankind is taking advantage of numerous services by small shallow lakes such as drinking water supply, irrigation, transportation, recreational function and aesthetic values; however, eutrophication drives many of them to a deteriorated state. Internal loading of phosphorus (P) may often be the main reason why shallow lakes are unresponsive to watershed nutrient management programs. In this case, removal of sediments enriched in P is a possible method to reduce the internal P loading.In our study, we examined the changes in sediment P mobility and internal phosphorus loading after excavation of a 1-ha highly eutrophicated lake in Viljandi, Estonia. For that, we measured redox potential of the surficial sediments, sediment pore water P concentrations and calculated diffusive fluxes in deepest location before excavation in 2015 and in three locations (close to the inflow, close the outflow, and in the center of the lake) after excavation in 2017. Additionally, total phosphorus (TP), iron (Fe), and fractions of P were determined from the sediments before and after excavation.The P fractionation analyses revealed an increase in P retention capacity after lake excavation, indicated by an increase in Fe/P ratio of the sediments. Moreover, we observed a decrease in the concentrations of potentially mobile forms of P, as labile-P and Fe-bound P at all sampling sites. However, we observed notable spatial differences. At the station that displayed the highest Fe/P ratio, the redox potential of the surficial sediments was highest and the pore water SRP concentrations had lowest value. The diffusive fluxes were found to be highest at a sampling site that displayed anoxia in the near-bottom water layer. The lake will be monitored also in 2018 for the changes in P mobility and water quality.

AB - Mankind is taking advantage of numerous services by small shallow lakes such as drinking water supply, irrigation, transportation, recreational function and aesthetic values; however, eutrophication drives many of them to a deteriorated state. Internal loading of phosphorus (P) may often be the main reason why shallow lakes are unresponsive to watershed nutrient management programs. In this case, removal of sediments enriched in P is a possible method to reduce the internal P loading.In our study, we examined the changes in sediment P mobility and internal phosphorus loading after excavation of a 1-ha highly eutrophicated lake in Viljandi, Estonia. For that, we measured redox potential of the surficial sediments, sediment pore water P concentrations and calculated diffusive fluxes in deepest location before excavation in 2015 and in three locations (close to the inflow, close the outflow, and in the center of the lake) after excavation in 2017. Additionally, total phosphorus (TP), iron (Fe), and fractions of P were determined from the sediments before and after excavation.The P fractionation analyses revealed an increase in P retention capacity after lake excavation, indicated by an increase in Fe/P ratio of the sediments. Moreover, we observed a decrease in the concentrations of potentially mobile forms of P, as labile-P and Fe-bound P at all sampling sites. However, we observed notable spatial differences. At the station that displayed the highest Fe/P ratio, the redox potential of the surficial sediments was highest and the pore water SRP concentrations had lowest value. The diffusive fluxes were found to be highest at a sampling site that displayed anoxia in the near-bottom water layer. The lake will be monitored also in 2018 for the changes in P mobility and water quality.

KW - 4111 Agronomy

KW - Eutrophication

KW - Lake restoration

KW - Phosphorus retention

KW - Sediment removal

M3 - Poster

ER -

Kiani M, Tammeorg O, Tammeorg P, Niemistö JP, Horppila JA, Simojoki AJ. Sediment internal phosphorus loading before and after excavation of a shallow lake. 2018. Poster session presented at LahtiLakes 2018 - Restoration of Eutrophic Lakes: Current Practices and Future Challenges, .