The contribution of tephra constituents during biogenic silica determination: implications for soil and palaeoecological studies
(2015) In Biogeosciences 12(12). p.3789-3804- Abstract
- Biogenic silica (BSi) is used as a proxy by soil scientists to identify biological effects on the Si cycle and by palaeoecologists to study environmental changes. Alkaline extractions are typically used to measure BSi in both terrestrial and aquatic environments. The dissolution properties of volcanic glass in tephra deposits and their nanocrystalline weathering products are hypothesized to overlap those of BSi; however, data to support this behaviour are lacking. The potential that Si-bearing fractions dissolve in alkaline media (Si-Alk) that do not necessarily correspond to BSi brings the applicability of BSi as a proxy into question. Here, analysis of 15 samples reported as tephra-containing allows us to reject the hypothesis that... (More)
- Biogenic silica (BSi) is used as a proxy by soil scientists to identify biological effects on the Si cycle and by palaeoecologists to study environmental changes. Alkaline extractions are typically used to measure BSi in both terrestrial and aquatic environments. The dissolution properties of volcanic glass in tephra deposits and their nanocrystalline weathering products are hypothesized to overlap those of BSi; however, data to support this behaviour are lacking. The potential that Si-bearing fractions dissolve in alkaline media (Si-Alk) that do not necessarily correspond to BSi brings the applicability of BSi as a proxy into question. Here, analysis of 15 samples reported as tephra-containing allows us to reject the hypothesis that tephra constituents produce an identical dissolution signal to that of BSi during alkaline extraction. We found that dissolution of volcanic glass shards is incomplete during alkaline dissolution. Simultaneous measurement of Al and Si used here during alkaline dissolution provides an important parameter to enable us to separate glass shard dissolution from dissolution of BSi and other Si-bearing fractions. The contribution from volcanic glass shards (between 0.2 and 4 wt % SiO2), the main constituent of distal tephra, during alkaline dissolution can be substantial depending on the total Si-Alk. Hence, soils and lake sediments with low BSi concentrations are highly sensitive to the additional dissolution from tephra constituents and its weathering products. We advise evaluation of the potential for volcanic or other non-biogenic contributions for all types of studies using BSi as an environmental proxy. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/7791128
- author
- Clymans, Wim LU ; Barao, L. ; Van der Putten, Nathalie LU ; Wastegard, S. ; Gisladottir, G. ; Björck, Svante LU ; Moine, B. ; Struyf, E. and Conley, Daniel LU
- organization
- publishing date
- 2015
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Biogeosciences
- volume
- 12
- issue
- 12
- pages
- 16 pages
- publisher
- Copernicus GmbH
- external identifiers
-
- wos:000357119000009
- scopus:84935031352
- ISSN
- 1726-4189
- DOI
- 10.5194/bg-12-3789-2015
- language
- English
- LU publication?
- yes
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- 9b90b2ed-75ee-40a7-8e39-3408befad9f4 (old id 7791128)
- date added to LUP
- 2016-04-01 09:54:54
- date last changed
- 2022-04-12 00:07:29
@article{9b90b2ed-75ee-40a7-8e39-3408befad9f4,
abstract = {{Biogenic silica (BSi) is used as a proxy by soil scientists to identify biological effects on the Si cycle and by palaeoecologists to study environmental changes. Alkaline extractions are typically used to measure BSi in both terrestrial and aquatic environments. The dissolution properties of volcanic glass in tephra deposits and their nanocrystalline weathering products are hypothesized to overlap those of BSi; however, data to support this behaviour are lacking. The potential that Si-bearing fractions dissolve in alkaline media (Si-Alk) that do not necessarily correspond to BSi brings the applicability of BSi as a proxy into question. Here, analysis of 15 samples reported as tephra-containing allows us to reject the hypothesis that tephra constituents produce an identical dissolution signal to that of BSi during alkaline extraction. We found that dissolution of volcanic glass shards is incomplete during alkaline dissolution. Simultaneous measurement of Al and Si used here during alkaline dissolution provides an important parameter to enable us to separate glass shard dissolution from dissolution of BSi and other Si-bearing fractions. The contribution from volcanic glass shards (between 0.2 and 4 wt % SiO2), the main constituent of distal tephra, during alkaline dissolution can be substantial depending on the total Si-Alk. Hence, soils and lake sediments with low BSi concentrations are highly sensitive to the additional dissolution from tephra constituents and its weathering products. We advise evaluation of the potential for volcanic or other non-biogenic contributions for all types of studies using BSi as an environmental proxy.}},
author = {{Clymans, Wim and Barao, L. and Van der Putten, Nathalie and Wastegard, S. and Gisladottir, G. and Björck, Svante and Moine, B. and Struyf, E. and Conley, Daniel}},
issn = {{1726-4189}},
language = {{eng}},
number = {{12}},
pages = {{3789--3804}},
publisher = {{Copernicus GmbH}},
series = {{Biogeosciences}},
title = {{The contribution of tephra constituents during biogenic silica determination: implications for soil and palaeoecological studies}},
url = {{http://dx.doi.org/10.5194/bg-12-3789-2015}},
doi = {{10.5194/bg-12-3789-2015}},
volume = {{12}},
year = {{2015}},
}