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Dan Hammarlund

Dan Hammarlund

Professor

Dan Hammarlund

Sediment Records Shed Light on Drivers of Decadal Iron Concentration Increase in a Boreal Lake

Författare

  • Caroline Björnerås
  • Gesa A. Weyhenmeyer
  • Dan Hammarlund
  • Per Persson
  • Emma Kritzberg

Summary, in English

Increasing iron (Fe) concentrations are found in lakes on a wide geographical scale but exact causes are still debated. The observed trends might result from increased Fe loading from the terrestrial catchment, but also from changes in how Fe distributes between the water column and the sediments. To get a better understanding of the causes we investigated whether there has been any change in the sediment formation of Fe sulfides (FeS) as an Fe sink in response to declining atmospheric sulfur (S) deposition during recent decades. For our study, we chose Lake Bolmen in southern Sweden, a lake for which we confirmed that Fe concentrations in the water column have strongly increased along with water color during 1966–2018. Our investigations showed that Fe accumulation and speciation varied independently of S accumulation patterns in the Lake Bolmen sediment record. Thus, we were not able to relate the positive trend in Fe concentrations to reduced FeS binding in the sediments. Furthermore, we found that Fe accumulation rates increased along with lake water Fe concentrations, indicating that increased catchment loading rather than a change in the distribution between the sediments and the water column has driven the increase in Fe concentrations. The increased loading may be due to land-use change in the form of an extensive expansion of coniferous forest during the past century. Altered forest management practices and increased precipitation may have led to enhanced weathering and erosion of organic soil layers under aging coniferous forest.

Avdelning/ar

  • Kvartärgeologi
  • Enhet akvatisk ekologi
  • MERGE: ModElling the Regional and Global Earth system
  • BECC: Biodiversity and Ecosystem services in a Changing Climate
  • Mikrobiologisk ekologi
  • MEMEG
  • Centrum för miljö- och klimatvetenskap (CEC)
  • Akvatisk ekologi

Publiceringsår

2022

Språk

Engelska

Publikation/Tidskrift/Serie

Journal of Geophysical Research - Biogeosciences

Volym

127

Issue

3

Dokumenttyp

Artikel i tidskrift

Förlag

Wiley

Ämne

  • Climate Research
  • Geosciences, Multidisciplinary
  • Geochemistry

Status

Published

Forskningsgrupp

  • Microbial Ecology
  • Aquatic Ecology

ISBN/ISSN/Övrigt

  • ISSN: 2169-8953