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Modern silicon dynamics of a small high-latitude subarctic lake

Zahajská, Petra LU orcid ; Olid, Carolina ; Stadmark, Johanna LU ; Fritz, Sherilyn C. ; Opfergelt, Sophie and Conley, Daniel LU (2021) In Biogeosciences 18(7). p.2325-2345
Abstract
High biogenic silica (BSi) concentration occurs sporadically in lake sediments throughout the world, however, the processes leading to high BSi concentrations varies. While BSi formation and preservation is expected to occur in silica-rich environments with high dissolved silicon (DSi) concentrations such as volcanic and hydrothermal inputs, the factors and mechanisms explaining high DSi and BSi concentrations in lakes remain unclear. We explored the factors responsible for the high BSi concentration in sediments of a small, high-latitude subarctic lake (Lake 850). To do this, we combined measurements of variations in stream discharges, DSi concentrations and stable Si isotopes in both lake and stream water with measurements of BSi content... (More)
High biogenic silica (BSi) concentration occurs sporadically in lake sediments throughout the world, however, the processes leading to high BSi concentrations varies. While BSi formation and preservation is expected to occur in silica-rich environments with high dissolved silicon (DSi) concentrations such as volcanic and hydrothermal inputs, the factors and mechanisms explaining high DSi and BSi concentrations in lakes remain unclear. We explored the factors responsible for the high BSi concentration in sediments of a small, high-latitude subarctic lake (Lake 850). To do this, we combined measurements of variations in stream discharges, DSi concentrations and stable Si isotopes in both lake and stream water with measurements of BSi content in lake sediments. Water, radon, and Si mass balances revealed the importance of groundwater discharge as a main source of DSi to the lake, with groundwater-derived DSi inputs 3 times higher than those from ephemeral stream inlets. After including all external DSi sources (i.e., inlets and groundwater discharge) and estimating the total BSi accumulation in the sediment, we show that diatom production consumes up to 79 % of total DSi input. Additionally, low sediment accumulation rates were observed based on the dated core. Our findings thus demonstrate that groundwater discharge and low mass accumulation rate can account for the high BSi accumulation during the last 150 cal. yr BP. Globally, lakes have been estimated to retain one fifth of the annual DSi delivery into the ocean. Well constrained lake mass balances, such as presented here, bring clarity to those estimates of the terrestrial Si cycle sinks. (Less)
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author
; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Biogeosciences
volume
18
issue
7
pages
2325 - 2345
publisher
Copernicus GmbH
external identifiers
  • scopus:85104078339
ISSN
1726-4189
DOI
10.5194/bg-2020-441
project
Diatom-rich sediment formation in lakes
Investigation of diatomite formation
Investigation of diatom-rich sediment formation
language
English
LU publication?
yes
id
4eec1090-a430-49de-8e5f-25649b796914
date added to LUP
2021-01-11 15:37:03
date last changed
2022-04-26 23:19:08
@article{4eec1090-a430-49de-8e5f-25649b796914,
  abstract     = {{High biogenic silica (BSi) concentration occurs sporadically in lake sediments throughout the world, however, the processes leading to high BSi concentrations varies. While BSi formation and preservation is expected to occur in silica-rich environments with high dissolved silicon (DSi) concentrations such as volcanic and hydrothermal inputs, the factors and mechanisms explaining high DSi and BSi concentrations in lakes remain unclear. We explored the factors responsible for the high BSi concentration in sediments of a small, high-latitude subarctic lake (Lake 850). To do this, we combined measurements of variations in stream discharges, DSi concentrations and stable Si isotopes in both lake and stream water with measurements of BSi content in lake sediments. Water, radon, and Si mass balances revealed the importance of groundwater discharge as a main source of DSi to the lake, with groundwater-derived DSi inputs 3 times higher than those from ephemeral stream inlets. After including all external DSi sources (i.e., inlets and groundwater discharge) and estimating the total BSi accumulation in the sediment, we show that diatom production consumes up to 79 % of total DSi input. Additionally, low sediment accumulation rates were observed based on the dated core. Our findings thus demonstrate that groundwater discharge and low mass accumulation rate can account for the high BSi accumulation during the last 150 cal. yr BP. Globally, lakes have been estimated to retain one fifth of the annual DSi delivery into the ocean. Well constrained lake mass balances, such as presented here, bring clarity to those estimates of the terrestrial Si cycle sinks.}},
  author       = {{Zahajská, Petra and Olid, Carolina and Stadmark, Johanna and Fritz, Sherilyn C. and Opfergelt, Sophie and Conley, Daniel}},
  issn         = {{1726-4189}},
  language     = {{eng}},
  number       = {{7}},
  pages        = {{2325--2345}},
  publisher    = {{Copernicus GmbH}},
  series       = {{Biogeosciences}},
  title        = {{Modern silicon dynamics of a small high-latitude subarctic lake}},
  url          = {{http://dx.doi.org/10.5194/bg-2020-441}},
  doi          = {{10.5194/bg-2020-441}},
  volume       = {{18}},
  year         = {{2021}},
}