The distribution and utility of sea‐level indicators in Eurasian sub‐Arctic salt marshes (White Sea,Russia) |
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| Authors: | Andrew C. Kemp Benjamin P. Horton Daria Nikitina Christopher H. Vane Marina Potapova Elizabeth Weber‐Bruya Stephen J. Culver Tatyana Repkina David F. Hill |
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| Affiliation: | 1. Department of Earth and Ocean Sciences, Tufts University, Medford, MA, USA;2. Sea Level Research, Department of Marine and Coastal Sciences , Rutgers University, New Brunswick, NJ, USA;3. Institute of Earth, Ocean & Atmospheric Sciences, Rutgers University, New Brunswick, NJ, USA;4. Earth Observatory of Singapore, Nanyang Technological University, Singapore, Singapore;5. Asian School of the Environment, Nanyang Technological University, Singapore, Singapore;6. Department of Earth and Space Science, West Chester University of Pennsylvania, West Chester, PA, USA;7. British Geological Survey, Environmental Science Centre, Nottingham, UK;8. Academy of Natural Sciences, Drexel University, Philadelphia, PA, USA;9. Department of Biodiversity, Earth and Environmental Science, Drexel University, Philadelphia, PA, USA;10. Department of Geological Sciences, East Carolina University, Greenville, NC, USA;11. Faculty of Geography, Lomonosov Moscow State University, Moscow, Russia;12. School of Civil and Construction Engineering, Oregon State University, Corvallis, USA |
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| Abstract: | In support of efforts to reconstruct relative sea level (RSL), we investigated the utility of foraminifera, diatoms and bulk‐sediment geochemistry (δ13C, C:N and parameters measured by Rock‐Eval pyrolysis) as sea‐level indicators in Eurasian sub‐Arctic salt marshes. At three salt marshes (<15 km apart) in Dvina Bay (White Sea, Russia), we collected surface sediment samples along transects from subtidal to Taiga forest environments. Foraminifera at all sites formed bipartite assemblages, where elevations below mean high higher water (MHHW) were dominated by Miliammina spp. and elevations between MHHW and the highest occurrence of foraminifera were dominated by Jadammina macrescens and Balticammina pseudomacrescens. Five high‐diversity groups of diatoms were identified and they displayed pronounced variability amongst the study sites. Bulk‐sediment geochemistry recognized two groups (clastic‐dominated environments below MHHW and organic‐rich environments above MHHW). As one group included subtidal elevations and the other included supratidal elevations, we conclude that the measured geochemical parameters are not stand‐alone sea‐level indicators. Core JT2012 captured a regressive sediment succession of clastic, tidal‐flat sediment overlain by salt‐marsh organic silt and freshwater peat. The salt‐marsh sediment accumulated at 2804±52 years before present and preserved foraminifera (Jadammina macrescens and Balticammina pseudomacrescens) with good analogy to modern assemblages indicating that RSL was +2.60±0.47 m at this time. Diatoms confirm that marine influence decreased through time, but the lack of analogy between modern and core assemblages limited their utility as sea‐level indicators. Geochemical parameters also indicate a reduction in marine influence through time. We conclude that RSL reconstructions derived from salt‐marsh sediment preserved beneath Eurasian sub‐Arctic peatlands can provide valuable insight into the spatio‐temporal evolution of the Fennoscandian and Eurasian ice sheets. |
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