Dan Hammarlund
Professor
The lake as an iron sink - new insights on the role of iron speciation
Författare
Summary, in English
The solubility and behavior of iron (Fe) in natural waters is tightly linked to Fe speciation, and Fe speciation likely influences how Fe distributes between the water column and sediments. In this study, the function of a lake as an Fe sink, with focus on the role of Fe speciation, was assessed for Lake Bolmen in southern Sweden. We found that a large fraction of the Fe flowing in to the lake was efficiently lost by sedimentation in the lake basin. Fe in inflowing water was a mix of organically complexed mononuclear Fe, Fe-(oxy)hydroxides and Fe-bearing clays, while surface sediments were composed of Fe-(oxy)hydroxides, Fe-bearing clays, Fe-bearing silicates and Fe sulfides. The absence of organically complexed Fe in the surface sediments indicates that the lake is mainly a sink for minerogenic fractions. Furthermore, while lakes are considered to be sinks of Fe, it has been suggested that this function may be impaired by increasing precipitation and consequently shorter water residence time. In this study there were large within- and between-year variations in precipitation and Fe concentrations. However, rather than smaller Fe losses to the sediments during wet years, within-lake losses tended to be larger due to higher loading of Fe from the catchment. Thus, forecasted increases in precipitation may result in enhanced catchment export and Fe loading to lakes, and subsequently enhanced Fe sequestration in sediments.
Avdelning/ar
- Enhet akvatisk ekologi
- Mikrobiologisk ekologi
- MEMEG
- Centrum för miljö- och klimatvetenskap (CEC)
- Kvartärgeologi
- Akvatisk ekologi
Publiceringsår
2021-12-05
Språk
Engelska
Publikation/Tidskrift/Serie
Chemical Geology
Volym
584
Dokumenttyp
Artikel i tidskrift
Förlag
Elsevier
Ämne
- Geochemistry
- Water Engineering
Nyckelord
- Browning
- Iron biogeochemistry
- Mass balance
- Organic carbon
- X-ray absorption spectroscopy
Status
Published
Forskningsgrupp
- Microbial Ecology
- Aquatic Ecology
ISBN/ISSN/Övrigt
- ISSN: 0009-2541