A bottom-up quantification of foliar mercury uptake fluxes across Europe
The exchange of gaseous elemental mercury, Hg(0), between the atmosphere and terrestrial surfaces remains poorly understood mainly due to difficulties in measuring net Hg(0) fluxes on the ecosystem scale. Emerging evidence suggests foliar uptake of atmospheric Hg(0) to be a major deposition pathway...
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ftdoajarticles:oai:doaj.org/article:bcb7bf0ca42c4fb5a25a8e40452b146c 2023-05-15T17:42:56+02:00 A bottom-up quantification of foliar mercury uptake fluxes across Europe L. Wohlgemuth S. Osterwalder C. Joseph A. Kahmen G. Hoch C. Alewell M. Jiskra 2020-12-01T00:00:00Z https://doi.org/10.5194/bg-17-6441-2020 https://doaj.org/article/bcb7bf0ca42c4fb5a25a8e40452b146c EN eng Copernicus Publications https://bg.copernicus.org/articles/17/6441/2020/bg-17-6441-2020.pdf https://doaj.org/toc/1726-4170 https://doaj.org/toc/1726-4189 doi:10.5194/bg-17-6441-2020 1726-4170 1726-4189 https://doaj.org/article/bcb7bf0ca42c4fb5a25a8e40452b146c Biogeosciences, Vol 17, Pp 6441-6456 (2020) Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 article 2020 ftdoajarticles https://doi.org/10.5194/bg-17-6441-2020 2022-12-31T06:54:14Z The exchange of gaseous elemental mercury, Hg(0), between the atmosphere and terrestrial surfaces remains poorly understood mainly due to difficulties in measuring net Hg(0) fluxes on the ecosystem scale. Emerging evidence suggests foliar uptake of atmospheric Hg(0) to be a major deposition pathway to terrestrial surfaces. Here, we present a bottom-up approach to calculate Hg(0) uptake fluxes to aboveground foliage by combining foliar Hg uptake rates normalized to leaf area with species-specific leaf area indices. This bottom-up approach incorporates systematic variations in crown height and needle age. We analyzed Hg content in 583 foliage samples from six tree species at 10 European forested research sites along a latitudinal gradient from Switzerland to northern Finland over the course of the 2018 growing season. Foliar Hg concentrations increased over time in all six tree species at all sites. We found that foliar Hg uptake rates normalized to leaf area were highest at the top of the tree crown. Foliar Hg uptake rates decreased with needle age of multiyear-old conifers (spruce and pine). Average species-specific foliar Hg uptake fluxes during the 2018 growing season were 18 ± 3 µg Hg m −2 for beech, 26 ± 5 µg Hg m −2 for oak, 4 ± 1 µg Hg m −2 for pine and 11 ± 1 µg Hg m −2 for spruce. For comparison, the average Hg(II) wet deposition flux measured at 5 of the 10 research sites during the same period was 2.3 ± 0.3 µg Hg m −2 , which was 4 times lower than the site-averaged foliar uptake flux of 10 ± 3 µg Hg m −2 . Scaling up site-specific foliar uptake rates to the forested area of Europe resulted in a total foliar Hg uptake flux of approximately 20 ± 3 Mg during the 2018 growing season. Considering that the same flux applies to the global land area of temperate forests, we estimate a foliar Hg uptake flux of 108 ± 18 Mg. Our data indicate that foliar Hg uptake is a major deposition pathway to terrestrial surfaces in Europe. The bottom-up approach provides a promising method to quantify foliar Hg uptake ... Article in Journal/Newspaper Northern Finland Directory of Open Access Journals: DOAJ Articles Biogeosciences 17 24 6441 6456 |
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Directory of Open Access Journals: DOAJ Articles |
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ftdoajarticles |
language |
English |
topic |
Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 |
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Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 L. Wohlgemuth S. Osterwalder C. Joseph A. Kahmen G. Hoch C. Alewell M. Jiskra A bottom-up quantification of foliar mercury uptake fluxes across Europe |
topic_facet |
Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 |
description |
The exchange of gaseous elemental mercury, Hg(0), between the atmosphere and terrestrial surfaces remains poorly understood mainly due to difficulties in measuring net Hg(0) fluxes on the ecosystem scale. Emerging evidence suggests foliar uptake of atmospheric Hg(0) to be a major deposition pathway to terrestrial surfaces. Here, we present a bottom-up approach to calculate Hg(0) uptake fluxes to aboveground foliage by combining foliar Hg uptake rates normalized to leaf area with species-specific leaf area indices. This bottom-up approach incorporates systematic variations in crown height and needle age. We analyzed Hg content in 583 foliage samples from six tree species at 10 European forested research sites along a latitudinal gradient from Switzerland to northern Finland over the course of the 2018 growing season. Foliar Hg concentrations increased over time in all six tree species at all sites. We found that foliar Hg uptake rates normalized to leaf area were highest at the top of the tree crown. Foliar Hg uptake rates decreased with needle age of multiyear-old conifers (spruce and pine). Average species-specific foliar Hg uptake fluxes during the 2018 growing season were 18 ± 3 µg Hg m −2 for beech, 26 ± 5 µg Hg m −2 for oak, 4 ± 1 µg Hg m −2 for pine and 11 ± 1 µg Hg m −2 for spruce. For comparison, the average Hg(II) wet deposition flux measured at 5 of the 10 research sites during the same period was 2.3 ± 0.3 µg Hg m −2 , which was 4 times lower than the site-averaged foliar uptake flux of 10 ± 3 µg Hg m −2 . Scaling up site-specific foliar uptake rates to the forested area of Europe resulted in a total foliar Hg uptake flux of approximately 20 ± 3 Mg during the 2018 growing season. Considering that the same flux applies to the global land area of temperate forests, we estimate a foliar Hg uptake flux of 108 ± 18 Mg. Our data indicate that foliar Hg uptake is a major deposition pathway to terrestrial surfaces in Europe. The bottom-up approach provides a promising method to quantify foliar Hg uptake ... |
format |
Article in Journal/Newspaper |
author |
L. Wohlgemuth S. Osterwalder C. Joseph A. Kahmen G. Hoch C. Alewell M. Jiskra |
author_facet |
L. Wohlgemuth S. Osterwalder C. Joseph A. Kahmen G. Hoch C. Alewell M. Jiskra |
author_sort |
L. Wohlgemuth |
title |
A bottom-up quantification of foliar mercury uptake fluxes across Europe |
title_short |
A bottom-up quantification of foliar mercury uptake fluxes across Europe |
title_full |
A bottom-up quantification of foliar mercury uptake fluxes across Europe |
title_fullStr |
A bottom-up quantification of foliar mercury uptake fluxes across Europe |
title_full_unstemmed |
A bottom-up quantification of foliar mercury uptake fluxes across Europe |
title_sort |
bottom-up quantification of foliar mercury uptake fluxes across europe |
publisher |
Copernicus Publications |
publishDate |
2020 |
url |
https://doi.org/10.5194/bg-17-6441-2020 https://doaj.org/article/bcb7bf0ca42c4fb5a25a8e40452b146c |
genre |
Northern Finland |
genre_facet |
Northern Finland |
op_source |
Biogeosciences, Vol 17, Pp 6441-6456 (2020) |
op_relation |
https://bg.copernicus.org/articles/17/6441/2020/bg-17-6441-2020.pdf https://doaj.org/toc/1726-4170 https://doaj.org/toc/1726-4189 doi:10.5194/bg-17-6441-2020 1726-4170 1726-4189 https://doaj.org/article/bcb7bf0ca42c4fb5a25a8e40452b146c |
op_doi |
https://doi.org/10.5194/bg-17-6441-2020 |
container_title |
Biogeosciences |
container_volume |
17 |
container_issue |
24 |
container_start_page |
6441 |
op_container_end_page |
6456 |
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1766144878987706368 |