SALT-MARSH TESTATE AMOEBAE AS SEA-LEVEL INDICATORS: VIĐARHÓLMI MARSH, WESTERN ICELAND.

• Main Author: Haynes, Steffie
• Other Authors: Faculty of Science
• Format: Thesis
• Language: English
• Published: University of Plymouth 2011
• Subjects: MSc Applied Marine Science; Iceland; North Atlantic
• Online Access: http://hdl.handle.net/10026.2/1423

Do testate amoebae represent a viable microfossil group to add to the sea-level scientist’s toolkit? Results are presented from an investigation into testate amoebae as sea-level indicators at Viđarhólmi marsh, western Iceland. Surface samples display a narrow vertical zonation relative to tidal height, with three principal zones characterised by taxa with variable tolerance to marine influence. These include the species from higher to lower elevations: Tracheleuglypha dentata, Centropyxis cassis, Centropyxis ecornis, Centropyxis platystoma and Difflugia pristis. This is comparable with work from both the UK and North America, suggesting that salt-marsh testate amoebae have similar distributions across the entire North Atlantic region (Charman et al.1998, 2002; Gehrels et al. 2001; Gehrels et al. 2006a; Charman et al. 2010). Though based on a relatively small data set, results indicate that testate amoebae can indicate former sea levels with a precision of ±5cm. Fossil testate amoebae were present in a short fossil section dated to AD 1230-1620, the oldest salt-marsh testate amoebae yet described. A sea-level reconstruction is presented spanning a period dated to AD 1330-1620 which is in reasonable, but not perfect agreement with the existing diatom-based reconstruction. The results from this work verify the potential of salt-marsh testate amoebae as sea-level indicators. Refinement of methodology is recommended such as sampling higher marsh areas where testate amoebae are most abundant, and by improving sample preparation techniques. This study contributes to the growing evidence that demonstrates the high potential of the application of testate amoebae analyses in studies of Holocene sea-level change. Faculty of Science & Technology