Temporal isotopic variations of dissolved silicon in a pristine boreal river

Abstract

The results implicate biogeochemical Si-cycling via formation and dissolution of biogenic silica as processes significantly affecting the dissolved Si transport in boreal systems during April to early October. The Si budget in the river system appeared to be controlled by relative Si enrichment during high discharge events and relative Si depletions in the subarctic mountainous and lake dominated areas. The Si enrichments and depletions were accompanied by decreasing and increasing riverine delta(29)Si and delta(30)Si, respectively. These isotope variations can be explained by release of plant derived silica, depleted in heavier Si isotopes, during the spring snowmelt. Further, increased volumetric contribution from the headwater and losses of dissolved Si due to biogenic silica formation by diatoms in the subarctic lakes at a later period are expected to be responsible for the preferential losses of lighter isotopes, as further verified by land cover analysis. (C) 2010 Elsevier By. All rights reserved.

Keywords

Silicon isotopic composition; Dissolved Si; Biogenic silica; Subarctic river system; Biogeochemical Si cycle; MC-ICPMS

Published in

Chemical Geology
2010, Volume: 271, number: 3-4, pages: 142-152 Publisher: ELSEVIER SCIENCE BV

SLU Authors

• Ecke, Frauke

  • Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences
    
  • Luleå University of Technology

Sustainable Development Goals

SDG14 Life below water


UKÄ Subject classification

Ecology


Publication identifier

DOI: https://doi.org/10.1016/j.chemgeo.2010.01.005

Permanent link to this page (URI)

https://res.slu.se/id/publ/39996