Impact of Holocene climate change on silicon cycling in Lake 850, Northern Sweden

• Published in: The Holocene
• Main Authors: Zahajská, Petra, Cartier, Rosine, Fritz, Sherilyn C, Stadmark, Johanna, Opfergelt, Sophie, Yam, Ruth, Shemesh, Aldo, Conley, Daniel J
• Format: Article in Journal/Newspaper
• Language: English
• Published: SAGE Publications 2021
• Subjects: Northern Sweden; Subarctic
• Online Access: https://doi.org/10.1177/09596836211025973; https://journals.sagepub.com/doi/pdf/10.1177/09596836211025973; https://journals.sagepub.com/doi/full-xml/10.1177/09596836211025973

Diatom-rich sediment in a small subarctic lake (Lake 850) was investigated in a 9400 cal. yr BP sediment record in order to explore the impact of Holocene climate evolution on silicon cycling. Diatom stable silicon isotopes ([Formula: see text]) and biogenic silica (BSi) indicate that high BSi concentrations in sediment throughout the Holocene are associated with a lighter Si isotope source of dissolved silica (DSi), such as groundwater or freshly weathered primary minerals. Furthermore, higher BSi concentrations were favoured during the mid-Holocene by low detrital inputs and possibly a longer ice-free period allowing for more diatom production to occur. The diatom [Formula: see text] signature shows a link to changes in regional climate and is influenced by length of diatom growth period and hydrological fluctuations. Lighter Si isotopic values occur during the mid-Holocene, when climate is inferred to be more continental and drier, with pronounced seasonality. In contrast, a heavier Si isotopic signature is observed in the early and late Holocene, when oceanic influences are thought to be stronger and the climate wetter. The [Formula: see text] values have generally lighter signatures as compared with other studies, which supports a light DSi source.