Iron in the Lena River basin, NE Russia : Insights from microscopy, spectroscopy and isotope analysis
Iron is an important mediator of biotic and abiotic processes on the Earth’s surface, being an electron acceptor in organic matter degradation, a surface for organic matter and trace element adsorption, and a required element for enzymatic processes during primary production. Yet, the role of iron a...
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Stockholms universitet, Institutionen för geologiska vetenskaper
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ftstockholmuniv:oai:DiVA.org:su-160797 2023-05-15T15:16:02+02:00 Iron in the Lena River basin, NE Russia : Insights from microscopy, spectroscopy and isotope analysis Hirst, Catherine 2018 application/pdf http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-160797 eng eng Stockholms universitet, Institutionen för geologiska vetenskaper Stockholm : Department of Geological Sciences, Stockholm University Meddelanden från Stockholms universitets institution för geologiska vetenskaper 375 http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-160797 urn:isbn:978-91-7797-414-7 urn:isbn:978-91-7797-415-4 info:eu-repo/semantics/openAccess iron reactivity isotopes permafrost river Arctic Geochemistry Geokemi Doctoral thesis, comprehensive summary info:eu-repo/semantics/doctoralThesis text 2018 ftstockholmuniv 2023-02-23T21:43:00Z Iron is an important mediator of biotic and abiotic processes on the Earth’s surface, being an electron acceptor in organic matter degradation, a surface for organic matter and trace element adsorption, and a required element for enzymatic processes during primary production. Yet, the role of iron as a mediator of carbon and trace element cycling in high latitude, permafrost-dominated regions remains poorly investigated. The aim of this study was to characterise the chemical reactivity (by size separation, microscopy and spectroscopy) and sources (by isotope composition) of Fe in the Lena River and major tributaries, spanning a wide range in lithology, topography and climate. The Fe transported in the Lena River and major tributaries carries an integrated signal of Fe weathering processes across the permafrost-dominated terrain. A spatial sample set was collected during the post-spring flood period (July 2012, June 2013), from the main channel and tributaries draining contrasting topography and permafrost extent. Across the basin, Fe is mainly transported as chemically reactive ferrihydrite that spans the particulate (> 0.22 µm) and colloidal (0.22 µm – 1 kDa) fractions. The remaining Fe transported as poorly reactive detrital Fe in clays and crystalline oxides. Fe is transported in larger size fractions than the dissolved OM showing that Fe is not a major carrier of DOM. Nano-sized ferrihydrite was attached to OM in the particulate fraction, evidence of a Fe – OM particle association in the Lena River basin. Ferrihydrite shows distinct isotope values in particulate and colloidal fractions, showing that there is a difference in isotopic composition between different size fractions of the same mineral. A conceptual model was developed to understand ferrihydrite formation in the riparian zone of the Lena River and tributaries. Particulate ferrihydrite has isotope values lower than crustal values resulting from redox and organic-ligand promoted mineral dissolution and precipitation of Fe(II)aq to form coatings ... Doctoral or Postdoctoral Thesis Arctic lena river permafrost Stockholm University: Publications (DiVA) Arctic |
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Open Polar |
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Stockholm University: Publications (DiVA) |
op_collection_id |
ftstockholmuniv |
language |
English |
topic |
iron reactivity isotopes permafrost river Arctic Geochemistry Geokemi |
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iron reactivity isotopes permafrost river Arctic Geochemistry Geokemi Hirst, Catherine Iron in the Lena River basin, NE Russia : Insights from microscopy, spectroscopy and isotope analysis |
topic_facet |
iron reactivity isotopes permafrost river Arctic Geochemistry Geokemi |
description |
Iron is an important mediator of biotic and abiotic processes on the Earth’s surface, being an electron acceptor in organic matter degradation, a surface for organic matter and trace element adsorption, and a required element for enzymatic processes during primary production. Yet, the role of iron as a mediator of carbon and trace element cycling in high latitude, permafrost-dominated regions remains poorly investigated. The aim of this study was to characterise the chemical reactivity (by size separation, microscopy and spectroscopy) and sources (by isotope composition) of Fe in the Lena River and major tributaries, spanning a wide range in lithology, topography and climate. The Fe transported in the Lena River and major tributaries carries an integrated signal of Fe weathering processes across the permafrost-dominated terrain. A spatial sample set was collected during the post-spring flood period (July 2012, June 2013), from the main channel and tributaries draining contrasting topography and permafrost extent. Across the basin, Fe is mainly transported as chemically reactive ferrihydrite that spans the particulate (> 0.22 µm) and colloidal (0.22 µm – 1 kDa) fractions. The remaining Fe transported as poorly reactive detrital Fe in clays and crystalline oxides. Fe is transported in larger size fractions than the dissolved OM showing that Fe is not a major carrier of DOM. Nano-sized ferrihydrite was attached to OM in the particulate fraction, evidence of a Fe – OM particle association in the Lena River basin. Ferrihydrite shows distinct isotope values in particulate and colloidal fractions, showing that there is a difference in isotopic composition between different size fractions of the same mineral. A conceptual model was developed to understand ferrihydrite formation in the riparian zone of the Lena River and tributaries. Particulate ferrihydrite has isotope values lower than crustal values resulting from redox and organic-ligand promoted mineral dissolution and precipitation of Fe(II)aq to form coatings ... |
format |
Doctoral or Postdoctoral Thesis |
author |
Hirst, Catherine |
author_facet |
Hirst, Catherine |
author_sort |
Hirst, Catherine |
title |
Iron in the Lena River basin, NE Russia : Insights from microscopy, spectroscopy and isotope analysis |
title_short |
Iron in the Lena River basin, NE Russia : Insights from microscopy, spectroscopy and isotope analysis |
title_full |
Iron in the Lena River basin, NE Russia : Insights from microscopy, spectroscopy and isotope analysis |
title_fullStr |
Iron in the Lena River basin, NE Russia : Insights from microscopy, spectroscopy and isotope analysis |
title_full_unstemmed |
Iron in the Lena River basin, NE Russia : Insights from microscopy, spectroscopy and isotope analysis |
title_sort |
iron in the lena river basin, ne russia : insights from microscopy, spectroscopy and isotope analysis |
publisher |
Stockholms universitet, Institutionen för geologiska vetenskaper |
publishDate |
2018 |
url |
http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-160797 |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic lena river permafrost |
genre_facet |
Arctic lena river permafrost |
op_relation |
Meddelanden från Stockholms universitets institution för geologiska vetenskaper 375 http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-160797 urn:isbn:978-91-7797-414-7 urn:isbn:978-91-7797-415-4 |
op_rights |
info:eu-repo/semantics/openAccess |
_version_ |
1766346354630590464 |