Quantifying the impact of freshwater diatom productivity on silicon isotopes and silicon fluxes : Lake Myvatn, Iceland
Diatom productivity in the oceans plays a crucial role in the carbon cycle, but is strongly dependent upon the continental silicon supply. However, the relative influence of weathering and biological processes on continental Si fluxes remains poorly constrained. This study aims to quantify the impac...
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ftunivlouvain:oai:dial.uclouvain.be:boreal:83128 2024-05-19T07:42:46+00:00 Quantifying the impact of freshwater diatom productivity on silicon isotopes and silicon fluxes : Lake Myvatn, Iceland Opfergelt, Sophie Eiriksdottir, E.S. Burton, K.W. Einarsson, A. Siebert, C Gislason, S.R. Halliday, A.N UCL - SST/ELI/ELIE - Environmental Sciences University of Iceland - n/ University of Oxford, Uk University of Iceland University of Oxford 2011 http://hdl.handle.net/2078.1/83128 https://doi.org/10.1016/j.epsl.2011.02.043 eng eng Elsevier BV boreal:83128 http://hdl.handle.net/2078.1/83128 doi:10.1016/j.epsl.2011.02.043 urn:ISSN:0012-821X info:eu-repo/semantics/restrictedAccess Earth and Planetary Science Letters, , no. 305, p. 73-82 (2011) silicon isotopes 3661 S590 info:eu-repo/semantics/article 2011 ftunivlouvain https://doi.org/10.1016/j.epsl.2011.02.043 2024-04-24T01:44:43Z Diatom productivity in the oceans plays a crucial role in the carbon cycle, but is strongly dependent upon the continental silicon supply. However, the relative influence of weathering and biological processes on continental Si fluxes remains poorly constrained. This study aims to quantify the impact of terrestrial diatom productivity on Si fluxes to the ocean. Lake Myvatn in North Iceland is one of the most productive lakes in the Northern Hemisphere, with nutrient-rich waters almost uniquely sourced by groundwater. The primary production is mainly controlled by diatom growth but also by cyanobacteria, and the lake output is via a single river, thereby providing a relatively simple natural laboratory to quantify the impact of diatom growth on the chemistry and Si budget of lake waters. Silicon stable isotopes (o^30Si) provide a tracer of this biocycling, and have been measured in groundwater inputs to the lake, and in time-series monitoring of waters at the lake outlet. The o^30Si values at the outlet range from + 0.70 ± 0.08 to + 1.42 ± 0.06‰, which is significantly heavier than the groundwater input (average cold and hot springs: + 0.50 ± 0.17‰, 2SD) and consistent with the preferential uptake of light Si isotopes by diatoms. The o^30Si value at the outlet increases by up to 0.9‰ in spring and autumn relative to the Si isotope composition of the inflow. These seasonal diatom blooms can be modeled by an open system of Si uptake and affect Si fluxes at the outlet of the lake by up to 79%, or 53% integrated over the year. In the summer a shift to lighter o^30Si values is correlated with a higher pH, which results in dissolution of diatoms releasing light Si isotopes. From mass balance, this seasonal diatom dissolution affects Si fluxes by up to 33%, but is limited to 3.7% integrated over the year. These results clearly illustrate that biological activity can have a significant impact on both isotope composition and elemental abundance of continental derived Si. They also demonstrate the pH dependency of ... Article in Journal/Newspaper Iceland DIAL@UCLouvain (Université catholique de Louvain) Earth and Planetary Science Letters 305 1-2 73 82 |
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Open Polar |
collection |
DIAL@UCLouvain (Université catholique de Louvain) |
op_collection_id |
ftunivlouvain |
language |
English |
topic |
silicon isotopes 3661 S590 |
spellingShingle |
silicon isotopes 3661 S590 Opfergelt, Sophie Eiriksdottir, E.S. Burton, K.W. Einarsson, A. Siebert, C Gislason, S.R. Halliday, A.N Quantifying the impact of freshwater diatom productivity on silicon isotopes and silicon fluxes : Lake Myvatn, Iceland |
topic_facet |
silicon isotopes 3661 S590 |
description |
Diatom productivity in the oceans plays a crucial role in the carbon cycle, but is strongly dependent upon the continental silicon supply. However, the relative influence of weathering and biological processes on continental Si fluxes remains poorly constrained. This study aims to quantify the impact of terrestrial diatom productivity on Si fluxes to the ocean. Lake Myvatn in North Iceland is one of the most productive lakes in the Northern Hemisphere, with nutrient-rich waters almost uniquely sourced by groundwater. The primary production is mainly controlled by diatom growth but also by cyanobacteria, and the lake output is via a single river, thereby providing a relatively simple natural laboratory to quantify the impact of diatom growth on the chemistry and Si budget of lake waters. Silicon stable isotopes (o^30Si) provide a tracer of this biocycling, and have been measured in groundwater inputs to the lake, and in time-series monitoring of waters at the lake outlet. The o^30Si values at the outlet range from + 0.70 ± 0.08 to + 1.42 ± 0.06‰, which is significantly heavier than the groundwater input (average cold and hot springs: + 0.50 ± 0.17‰, 2SD) and consistent with the preferential uptake of light Si isotopes by diatoms. The o^30Si value at the outlet increases by up to 0.9‰ in spring and autumn relative to the Si isotope composition of the inflow. These seasonal diatom blooms can be modeled by an open system of Si uptake and affect Si fluxes at the outlet of the lake by up to 79%, or 53% integrated over the year. In the summer a shift to lighter o^30Si values is correlated with a higher pH, which results in dissolution of diatoms releasing light Si isotopes. From mass balance, this seasonal diatom dissolution affects Si fluxes by up to 33%, but is limited to 3.7% integrated over the year. These results clearly illustrate that biological activity can have a significant impact on both isotope composition and elemental abundance of continental derived Si. They also demonstrate the pH dependency of ... |
author2 |
UCL - SST/ELI/ELIE - Environmental Sciences University of Iceland - n/ University of Oxford, Uk University of Iceland University of Oxford |
format |
Article in Journal/Newspaper |
author |
Opfergelt, Sophie Eiriksdottir, E.S. Burton, K.W. Einarsson, A. Siebert, C Gislason, S.R. Halliday, A.N |
author_facet |
Opfergelt, Sophie Eiriksdottir, E.S. Burton, K.W. Einarsson, A. Siebert, C Gislason, S.R. Halliday, A.N |
author_sort |
Opfergelt, Sophie |
title |
Quantifying the impact of freshwater diatom productivity on silicon isotopes and silicon fluxes : Lake Myvatn, Iceland |
title_short |
Quantifying the impact of freshwater diatom productivity on silicon isotopes and silicon fluxes : Lake Myvatn, Iceland |
title_full |
Quantifying the impact of freshwater diatom productivity on silicon isotopes and silicon fluxes : Lake Myvatn, Iceland |
title_fullStr |
Quantifying the impact of freshwater diatom productivity on silicon isotopes and silicon fluxes : Lake Myvatn, Iceland |
title_full_unstemmed |
Quantifying the impact of freshwater diatom productivity on silicon isotopes and silicon fluxes : Lake Myvatn, Iceland |
title_sort |
quantifying the impact of freshwater diatom productivity on silicon isotopes and silicon fluxes : lake myvatn, iceland |
publisher |
Elsevier BV |
publishDate |
2011 |
url |
http://hdl.handle.net/2078.1/83128 https://doi.org/10.1016/j.epsl.2011.02.043 |
genre |
Iceland |
genre_facet |
Iceland |
op_source |
Earth and Planetary Science Letters, , no. 305, p. 73-82 (2011) |
op_relation |
boreal:83128 http://hdl.handle.net/2078.1/83128 doi:10.1016/j.epsl.2011.02.043 urn:ISSN:0012-821X |
op_rights |
info:eu-repo/semantics/restrictedAccess |
op_doi |
https://doi.org/10.1016/j.epsl.2011.02.043 |
container_title |
Earth and Planetary Science Letters |
container_volume |
305 |
container_issue |
1-2 |
container_start_page |
73 |
op_container_end_page |
82 |
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1799482474084958208 |