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The stability of Fe...
The stability of Fe isotope signatures during low salinity mixing in subarctic estuaries
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- Conrad, Sarah (författare)
- Luleå tekniska universitet,Geovetenskap och miljöteknik
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- Wuttig, Kathrin (författare)
- GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany. Antarctic Climate and Ecosystems Cooperative Research Centre, University of Tasmania, Hobart, Australia
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- Jansen, Nils (författare)
- GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany. Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Australia
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- Rodushkin, Ilia (författare)
- ALS Laboratory Group, ALS Scandinavia AB, Luleå, Sweden
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- Ingri, Johan (författare)
- Luleå tekniska universitet,Geovetenskap och miljöteknik
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(creator_code:org_t)
- 2019-11-06
- 2019
- Engelska.
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Ingår i: Aquatic geochemistry. - : Springer. - 1380-6165 .- 1573-1421. ; 25:5-6, s. 195-218
- Relaterad länk:
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https://link.springe...
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https://urn.kb.se/re...
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https://doi.org/10.1...
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Abstract
Ämnesord
Stäng
- We have studied iron (Fe)-isotope signals in particles (> 0.22 µm) and the dissolved phase (< 0.22 µm) in two subarctic, boreal rivers, their estuaries and the adjacent sea in northern Sweden. Both rivers, the Råne and the Kalix, are enriched in Fe and organic carbon (up to 29 µmol/L and up to 730 µmol/L, respectively). Observed changes in the particulate and dissolved phase during spring flood in May suggest different sources of Fe to the rivers during different seasons. While particles show a positive Fe-isotope signal during winter, during spring flood, the values are negative. Increased discharge due to snowmelt in the boreal region is most times accompanied by flushing of the organic-rich sub-surface layers. These upper podzol soil layers have been shown to be a source for Fe-organic carbon aggregates with a negative Fe-isotope signal. During winter, the rivers are mostly fed by deep groundwater, where Fe occurs as Fe(oxy)hydroxides, with a positive Fe-isotope signal. Flocculation during initial estuarine mixing does not change the Fe-isotope compositions of the two phases. Data indicate that the two groups of Fe aggregates flocculate diversely in the estuaries due to differences in their surface structure. Within the open sea, the particulate phase showed heavier δ56Fe values than in the estuaries. Our data indicate the flocculation of the negative Fe-isotope signal in a low salinity environment, due to changes in the ionic strength and further the increase of pH.
Ämnesord
- NATURVETENSKAP -- Geovetenskap och miljövetenskap -- Geokemi (hsv//swe)
- NATURAL SCIENCES -- Earth and Related Environmental Sciences -- Geochemistry (hsv//eng)
Nyckelord
- Fe-isotopes
- Fe geochemistry
- Dissolved and particulate Fe
- Organically complexed Fe
- Fe(oxy)hydroxides
- Salinity gradient
- Spring flood
- Applied Geochemistry
- Tillämpad geokemi
Publikations- och innehållstyp
- ref (ämneskategori)
- art (ämneskategori)
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