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Tracing silicon cycling in the Okavango Delta, a sub-tropical flood-pulse wetland using silicon isotopes

Frings, Patrick LU ; De La Rocha, Christina; Struyf, Eric; van Pelt, Dimitri; Schoelynck, Jonas; Hudson, Mike Murray; Gondwe, Mangaliso J.; Wolski, Piotr; Mosimane, Keotsheple and Gray, William, et al. (2014) In Geochimica et Cosmochimica Acta 142. p.132-148
Abstract
Chemical weathering of silicate minerals releases elements into solution whereas the neoformation of secondary minerals

works in the opposite direction, potentially confounding estimates of silicate weathering rates. Silicon isotopes (d30Si) may be

a useful tool to investigate these processes. Here, we present 82 d30Si measurements from surface waters, pore waters, biogenic

silica (BSi), clays, sand and vegetation from the Okavango Delta, Botswana, a freshwater sub-tropical, flood-pulse wetland.

Hydrologically, the Okavango is dominated by evapotranspiration water losses to the atmosphere. It receives an annual pulse

of water that inundates seasonal floodplains, while river baseflow is... (More)
Chemical weathering of silicate minerals releases elements into solution whereas the neoformation of secondary minerals

works in the opposite direction, potentially confounding estimates of silicate weathering rates. Silicon isotopes (d30Si) may be

a useful tool to investigate these processes. Here, we present 82 d30Si measurements from surface waters, pore waters, biogenic

silica (BSi), clays, sand and vegetation from the Okavango Delta, Botswana, a freshwater sub-tropical, flood-pulse wetland.

Hydrologically, the Okavango is dominated by evapotranspiration water losses to the atmosphere. It receives an annual pulse

of water that inundates seasonal floodplains, while river baseflow is sufficient to maintain a permanent floodplain. d30Si in

dissolved silica (DSi) in surface waters along a 300 km transect at near-peak flood show a limited range (0.36–1.19&), imply-

ing the Delta is well buffered by a balance of processes adding and removing DSi from the surface water. A key control on DSi

concentrations is the uptake, production of BSi and recycling of Si by aquatic vegetation, although the net isotopic effect is

necessarily small since all BSi re-dissolves on short timescales. In the sediments, BSi d30Si (n = 30) ranges from (Less)
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Geochimica et Cosmochimica Acta
volume
142
pages
132 - 148
publisher
Elsevier
external identifiers
  • wos:000342622400010
  • scopus:84908037173
ISSN
0016-7037
DOI
10.1016/j.gca.2014.07.007
language
English
LU publication?
yes
id
07d2b8f8-e7ea-48e2-a7d7-c3e3c9f36a81 (old id 4695158)
date added to LUP
2014-11-27 11:07:40
date last changed
2017-07-09 03:19:53
@article{07d2b8f8-e7ea-48e2-a7d7-c3e3c9f36a81,
  abstract     = {Chemical weathering of silicate minerals releases elements into solution whereas the neoformation of secondary minerals<br/><br>
works in the opposite direction, potentially confounding estimates of silicate weathering rates. Silicon isotopes (d30Si) may be<br/><br>
a useful tool to investigate these processes. Here, we present 82 d30Si measurements from surface waters, pore waters, biogenic<br/><br>
silica (BSi), clays, sand and vegetation from the Okavango Delta, Botswana, a freshwater sub-tropical, flood-pulse wetland.<br/><br>
Hydrologically, the Okavango is dominated by evapotranspiration water losses to the atmosphere. It receives an annual pulse<br/><br>
of water that inundates seasonal floodplains, while river baseflow is sufficient to maintain a permanent floodplain. d30Si in<br/><br>
dissolved silica (DSi) in surface waters along a 300 km transect at near-peak flood show a limited range (0.36–1.19&amp;), imply-<br/><br>
ing the Delta is well buffered by a balance of processes adding and removing DSi from the surface water. A key control on DSi<br/><br>
concentrations is the uptake, production of BSi and recycling of Si by aquatic vegetation, although the net isotopic effect is<br/><br>
necessarily small since all BSi re-dissolves on short timescales. In the sediments, BSi d30Si (n = 30) ranges from},
  author       = {Frings, Patrick and De La Rocha, Christina and Struyf, Eric and van Pelt, Dimitri and Schoelynck, Jonas and Hudson, Mike Murray and Gondwe, Mangaliso J. and Wolski, Piotr and Mosimane, Keotsheple and Gray, William and Schaller, Jörg and Conley, Daniel},
  issn         = {0016-7037},
  language     = {eng},
  pages        = {132--148},
  publisher    = {Elsevier},
  series       = {Geochimica et Cosmochimica Acta},
  title        = {Tracing silicon cycling in the Okavango Delta, a sub-tropical flood-pulse wetland using silicon isotopes},
  url          = {http://dx.doi.org/10.1016/j.gca.2014.07.007},
  volume       = {142},
  year         = {2014},
}