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Nitrogen removal processes in lakes of different trophic states from on-site measurements and historic data

Freshwater lakes are essential hotspots for the removal of excessive anthropogenic nitrogen (N) loads transported from the land to coastal oceans. The biogeochemical processes responsible for N removal, the corresponding transformation rates and overall removal efficiencies differ between lakes, how...

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Autores principales: Müller, Beat, Thoma, Raoul, Baumann, Kathrin B. L., Callbeck, Cameron M., Schubert, Carsten J.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Springer International Publishing 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7946664/
https://www.ncbi.nlm.nih.gov/pubmed/33785997
http://dx.doi.org/10.1007/s00027-021-00795-7
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author Müller, Beat
Thoma, Raoul
Baumann, Kathrin B. L.
Callbeck, Cameron M.
Schubert, Carsten J.
author_facet Müller, Beat
Thoma, Raoul
Baumann, Kathrin B. L.
Callbeck, Cameron M.
Schubert, Carsten J.
author_sort Müller, Beat
collection PubMed
description Freshwater lakes are essential hotspots for the removal of excessive anthropogenic nitrogen (N) loads transported from the land to coastal oceans. The biogeochemical processes responsible for N removal, the corresponding transformation rates and overall removal efficiencies differ between lakes, however, it is unclear what the main controlling factors are. Here, we investigated the factors that moderate the rates of N removal under contrasting trophic states in two lakes located in central Switzerland. In the eutrophic Lake Baldegg and the oligotrophic Lake Sarnen, we specifically examined seasonal sediment porewater chemistry, organic matter sedimentation rates, as well as 33-year of historic water column data. We find that the eutrophic Lake Baldegg, which contributed to the removal of 20 ± 6.6 gN m(−2) year(−1), effectively removed two-thirds of the total areal N load. In stark contrast, the more oligotrophic Lake Sarnen contributed to 3.2 ± 4.2 gN m(−2) year(−1), and had removed only one-third of the areal N load. The historic dataset of the eutrophic lake revealed a close linkage between annual loads of dissolved N (DN) and removal rates (NRR = 0.63 × DN load) and a significant correlation of the concentration of bottom water nitrate and removal rates. We further show that the seasonal increase in N removal rates of the eutrophic lake correlated significantly with seasonal oxygen fluxes measured across the water–sediment interface (R(2) = 0.75). We suggest that increasing oxygen enhances sediment mineralization and stimulates nitrification, indirectly enhancing denitrification activity. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00027-021-00795-7.
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spelling pubmed-79466642021-03-28 Nitrogen removal processes in lakes of different trophic states from on-site measurements and historic data Müller, Beat Thoma, Raoul Baumann, Kathrin B. L. Callbeck, Cameron M. Schubert, Carsten J. Aquat Sci Research Article Freshwater lakes are essential hotspots for the removal of excessive anthropogenic nitrogen (N) loads transported from the land to coastal oceans. The biogeochemical processes responsible for N removal, the corresponding transformation rates and overall removal efficiencies differ between lakes, however, it is unclear what the main controlling factors are. Here, we investigated the factors that moderate the rates of N removal under contrasting trophic states in two lakes located in central Switzerland. In the eutrophic Lake Baldegg and the oligotrophic Lake Sarnen, we specifically examined seasonal sediment porewater chemistry, organic matter sedimentation rates, as well as 33-year of historic water column data. We find that the eutrophic Lake Baldegg, which contributed to the removal of 20 ± 6.6 gN m(−2) year(−1), effectively removed two-thirds of the total areal N load. In stark contrast, the more oligotrophic Lake Sarnen contributed to 3.2 ± 4.2 gN m(−2) year(−1), and had removed only one-third of the areal N load. The historic dataset of the eutrophic lake revealed a close linkage between annual loads of dissolved N (DN) and removal rates (NRR = 0.63 × DN load) and a significant correlation of the concentration of bottom water nitrate and removal rates. We further show that the seasonal increase in N removal rates of the eutrophic lake correlated significantly with seasonal oxygen fluxes measured across the water–sediment interface (R(2) = 0.75). We suggest that increasing oxygen enhances sediment mineralization and stimulates nitrification, indirectly enhancing denitrification activity. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00027-021-00795-7. Springer International Publishing 2021-03-10 2021 /pmc/articles/PMC7946664/ /pubmed/33785997 http://dx.doi.org/10.1007/s00027-021-00795-7 Text en © The Author(s) 2021 https://creativecommons.org/licenses/by/4.0/Open AccessThis article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/ (https://creativecommons.org/licenses/by/4.0/) .
spellingShingle Research Article
Müller, Beat
Thoma, Raoul
Baumann, Kathrin B. L.
Callbeck, Cameron M.
Schubert, Carsten J.
Nitrogen removal processes in lakes of different trophic states from on-site measurements and historic data
title Nitrogen removal processes in lakes of different trophic states from on-site measurements and historic data
title_full Nitrogen removal processes in lakes of different trophic states from on-site measurements and historic data
title_fullStr Nitrogen removal processes in lakes of different trophic states from on-site measurements and historic data
title_full_unstemmed Nitrogen removal processes in lakes of different trophic states from on-site measurements and historic data
title_short Nitrogen removal processes in lakes of different trophic states from on-site measurements and historic data
title_sort nitrogen removal processes in lakes of different trophic states from on-site measurements and historic data
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7946664/
https://www.ncbi.nlm.nih.gov/pubmed/33785997
http://dx.doi.org/10.1007/s00027-021-00795-7
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