Predicting the future of northern North Atlantic shallow water ecosystems from fossil bio-archives
A comprehensive understanding of past climates and environmental conditions is essential for our ability to successfully predict the likely impacts of future climate change and to effectively employ adaptation and mitigation strategies. The continued improvement and verification of numerical global...
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| Other Authors: | , |
| Format: | Doctoral or Postdoctoral Thesis |
| Language: | English |
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Universität Bremen
2014
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| Online Access: | https://media.suub.uni-bremen.de/handle/elib/749 https://nbn-resolving.org/urn:nbn:de:gbv:46-00104053-13 |
| Summary: | A comprehensive understanding of past climates and environmental conditions is essential for our ability to successfully predict the likely impacts of future climate change and to effectively employ adaptation and mitigation strategies. The continued improvement and verification of numerical global circulation models (GCMs) is our best tool for predicting future climate scenarios. However, longer time-scale reconstructions particularly rely on archives (e.g., ice cores, sediment cores) that contain preserved records of past conditions (proxies) in their biogenic hard parts (e.g., shells, bones, teeth) or non-biogenic deposits/accumulations (e.g., lake varves, layers in stalagmites or ice cores). The marine bivalve Arctica islandica is one such versatile and commonly used biogenic archive. Its key advantages are its longevity (up to 500 years old), its wide distribution throughout the North Atlantic and its abundance in the fossil record (back to 20 Ma). Variability in shell growth and the biogeochemistry of its shell carbonate (aragonite) enable reconstructions of, for example, large-scale ocean-atmosphere phenomena such as the North Atlantic Oscillation and sub-annual (seasonal) absolute water temperatures (based on stable oxygen isotopes). This well understood and wellcalibrated archive has most commonly been used for environmental reconstructions in the last 2,000 years but its full potential for climate reconstructions further back in time has not yet been fully exploited. Therefore, this thesis aims to thoroughly assess the potential of sub-fossil (up to 10,000 years old) and fossil A. islandica shell specimens as a palaeo-archive that records the environmental conditions of the North Atlantic during past warm phases. The use of any proxy data from fossil specimens presents challenges that can significantly impact upon palaeo-environmental interpretations. I firstly present a new methodology using confocal Raman microscopy (CRM) as a powerful sclerochronological tool for assessing preservation and ... |
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