Trophic state decrease after lanthanum-modified bentonite (Phoslock) application to a hyper-eutrophic polymictic urban lake frequented by Canada geese ( Branta canadensis )
Urban lakes are important assets to highly populated regions; however, extensive usage and other influences degrade their water quality, which then requires rehabilitation and maintenance. Hyper-eutrophic Swan Lake, Greater Toronto, Canada (5.5 ha, 4.4 m maximum depth) was a gravel pit that became d...
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ftdatacite:10.6084/m9.figshare.2077483.v1 2023-05-15T15:46:17+02:00 Trophic state decrease after lanthanum-modified bentonite (Phoslock) application to a hyper-eutrophic polymictic urban lake frequented by Canada geese ( Branta canadensis ) Nürnberg, Gertrud K. LaZerte, Bruce D. 2016 https://dx.doi.org/10.6084/m9.figshare.2077483.v1 https://tandf.figshare.com/articles/Trophic_state_decrease_after_lanthanum_modified_bentonite_Phoslock_application_to_a_hyper_eutrophic_polymictic_urban_lake_frequented_by_Canada_geese_i_Branta_canadensis_i_/2077483/1 unknown Taylor & Francis https://dx.doi.org/10.1080/10402381.2015.1133739 https://dx.doi.org/10.6084/m9.figshare.2077483 Creative Commons Attribution 4.0 International https://creativecommons.org/licenses/by/4.0/legalcode cc-by-4.0 CC-BY 59999 Environmental Sciences not elsewhere classified FOS Earth and related environmental sciences Ecology FOS Biological sciences 69999 Biological Sciences not elsewhere classified Inorganic Chemistry FOS Chemical sciences Text article-journal Journal contribution ScholarlyArticle 2016 ftdatacite https://doi.org/10.6084/m9.figshare.2077483.v1 https://doi.org/10.1080/10402381.2015.1133739 https://doi.org/10.6084/m9.figshare.2077483 2021-11-05T12:55:41Z Urban lakes are important assets to highly populated regions; however, extensive usage and other influences degrade their water quality, which then requires rehabilitation and maintenance. Hyper-eutrophic Swan Lake, Greater Toronto, Canada (5.5 ha, 4.4 m maximum depth) was a gravel pit that became degraded by elevated total phosphorus (TP) concentrations, mostly from internal P sources. Because Swan Lake is a terminal lake with limited flushing and small external load, a phosphate adsorbing and sediment capping agent, lanthanum-modified bentonite (Phoslock), was applied in spring 2013 to intercept the internal load. Average TP concentration decreased from 0.247 to 0.099 mg/L in the first and 0.060 mg/L in the second post-treatment year. A TP mass balance model adequately predicted post-treatment annual average TP concentration by not including the pre-treatment internal load estimate of 650 to 1100 mg/m 2 /yr. Phytoplankton biomass decreased only in the second post-treatment year, when Secchi transparency (highly correlated with chlorophyll concentration) increased to a growing season average of 1.4 m (range 0.7–2.7) compared to 0.5 m (0.37–0.63) before treatment. We explain the lack of response in the first treatment year with a relatively late application (29 Apr–1 May 2013), when P released from the winter bottom sediments had already been taken up by phytoplankton. Recently, a growing population of waterfowl (mostly Canada goose, Branta canadensis ) were the highest contributors of nutrients (75%), as indicated by a mass balance based on literature-derived goose P export and biweekly bird census. We recommend waterfowl management or repeated treatment to further improve water quality. Text Branta canadensis Canada Goose DataCite Metadata Store (German National Library of Science and Technology) Canada Urban Lake ENVELOPE(-106.034,-106.034,57.583,57.583) |
institution |
Open Polar |
collection |
DataCite Metadata Store (German National Library of Science and Technology) |
op_collection_id |
ftdatacite |
language |
unknown |
topic |
59999 Environmental Sciences not elsewhere classified FOS Earth and related environmental sciences Ecology FOS Biological sciences 69999 Biological Sciences not elsewhere classified Inorganic Chemistry FOS Chemical sciences |
spellingShingle |
59999 Environmental Sciences not elsewhere classified FOS Earth and related environmental sciences Ecology FOS Biological sciences 69999 Biological Sciences not elsewhere classified Inorganic Chemistry FOS Chemical sciences Nürnberg, Gertrud K. LaZerte, Bruce D. Trophic state decrease after lanthanum-modified bentonite (Phoslock) application to a hyper-eutrophic polymictic urban lake frequented by Canada geese ( Branta canadensis ) |
topic_facet |
59999 Environmental Sciences not elsewhere classified FOS Earth and related environmental sciences Ecology FOS Biological sciences 69999 Biological Sciences not elsewhere classified Inorganic Chemistry FOS Chemical sciences |
description |
Urban lakes are important assets to highly populated regions; however, extensive usage and other influences degrade their water quality, which then requires rehabilitation and maintenance. Hyper-eutrophic Swan Lake, Greater Toronto, Canada (5.5 ha, 4.4 m maximum depth) was a gravel pit that became degraded by elevated total phosphorus (TP) concentrations, mostly from internal P sources. Because Swan Lake is a terminal lake with limited flushing and small external load, a phosphate adsorbing and sediment capping agent, lanthanum-modified bentonite (Phoslock), was applied in spring 2013 to intercept the internal load. Average TP concentration decreased from 0.247 to 0.099 mg/L in the first and 0.060 mg/L in the second post-treatment year. A TP mass balance model adequately predicted post-treatment annual average TP concentration by not including the pre-treatment internal load estimate of 650 to 1100 mg/m 2 /yr. Phytoplankton biomass decreased only in the second post-treatment year, when Secchi transparency (highly correlated with chlorophyll concentration) increased to a growing season average of 1.4 m (range 0.7–2.7) compared to 0.5 m (0.37–0.63) before treatment. We explain the lack of response in the first treatment year with a relatively late application (29 Apr–1 May 2013), when P released from the winter bottom sediments had already been taken up by phytoplankton. Recently, a growing population of waterfowl (mostly Canada goose, Branta canadensis ) were the highest contributors of nutrients (75%), as indicated by a mass balance based on literature-derived goose P export and biweekly bird census. We recommend waterfowl management or repeated treatment to further improve water quality. |
format |
Text |
author |
Nürnberg, Gertrud K. LaZerte, Bruce D. |
author_facet |
Nürnberg, Gertrud K. LaZerte, Bruce D. |
author_sort |
Nürnberg, Gertrud K. |
title |
Trophic state decrease after lanthanum-modified bentonite (Phoslock) application to a hyper-eutrophic polymictic urban lake frequented by Canada geese ( Branta canadensis ) |
title_short |
Trophic state decrease after lanthanum-modified bentonite (Phoslock) application to a hyper-eutrophic polymictic urban lake frequented by Canada geese ( Branta canadensis ) |
title_full |
Trophic state decrease after lanthanum-modified bentonite (Phoslock) application to a hyper-eutrophic polymictic urban lake frequented by Canada geese ( Branta canadensis ) |
title_fullStr |
Trophic state decrease after lanthanum-modified bentonite (Phoslock) application to a hyper-eutrophic polymictic urban lake frequented by Canada geese ( Branta canadensis ) |
title_full_unstemmed |
Trophic state decrease after lanthanum-modified bentonite (Phoslock) application to a hyper-eutrophic polymictic urban lake frequented by Canada geese ( Branta canadensis ) |
title_sort |
trophic state decrease after lanthanum-modified bentonite (phoslock) application to a hyper-eutrophic polymictic urban lake frequented by canada geese ( branta canadensis ) |
publisher |
Taylor & Francis |
publishDate |
2016 |
url |
https://dx.doi.org/10.6084/m9.figshare.2077483.v1 https://tandf.figshare.com/articles/Trophic_state_decrease_after_lanthanum_modified_bentonite_Phoslock_application_to_a_hyper_eutrophic_polymictic_urban_lake_frequented_by_Canada_geese_i_Branta_canadensis_i_/2077483/1 |
long_lat |
ENVELOPE(-106.034,-106.034,57.583,57.583) |
geographic |
Canada Urban Lake |
geographic_facet |
Canada Urban Lake |
genre |
Branta canadensis Canada Goose |
genre_facet |
Branta canadensis Canada Goose |
op_relation |
https://dx.doi.org/10.1080/10402381.2015.1133739 https://dx.doi.org/10.6084/m9.figshare.2077483 |
op_rights |
Creative Commons Attribution 4.0 International https://creativecommons.org/licenses/by/4.0/legalcode cc-by-4.0 |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.6084/m9.figshare.2077483.v1 https://doi.org/10.1080/10402381.2015.1133739 https://doi.org/10.6084/m9.figshare.2077483 |
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