Late quaternary environmental change at Lake McKenzie, Southeast Queensland: evidence from microfossils, biomarkers and stable isotope analysis
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Date
2013-07-10
Journal Title
Journal ISSN
Volume Title
Publisher
University of Western Australia
Abstract
Unravelling links between climate change and vegetation response during the
Quaternary is a research priority, and needed if the climate-environment interactions of
modern systems are to be fully understood. Using a sediment core from Lake McKenzie,
Fraser Island, we reconstruct changes in the lake ecosystem and surrounding vegetation over
the last ca. 36.9 cal kyr BP. Evidence is drawn from multiple sources, including pollen,
micro-charcoal, biomarker and stable isotope (C and N) analyses, and is used to improve
understanding about the timing and spatial scale of past changes that have occurred locally
and in the southeast Queensland region. The glacial period of the record, from ca. 36.9-18.3
cal kyr BP, is characterised by lower lake water levels and increased abundance of, or closer
proximity to, plants of the aquatic and littoral zone. High abundance of biomarkers and
microfossils of the colonial green alga Botryococcus occur at this time and include high
variation in individual botryococcene
13C values. A distinct period of dry or ephemeral
conditions at the site is detected during deglaciation, causing a hiatus in the sedimentary
record covering the time period from ca. 18.3-14.0 cal kyr BP. The recommencement of
sediment accumulation around 14.0 cal kyr BP occurs with evidence of lower fire activity in
the area and reduced abundance of terrestrial herbs in the surrounding sclerophyll vegetation.
The Lake McKenzie record conforms to existing records from Fraser Island by containing
evidence for a mid-Holocene dry period, spanning the time period from ca. 6.1-2.5 cal kyr
BP. © The Authors
Description
Keywords
Quaternary period, Environment, Ecosystems, Lakes, Queensland, Australia, Fossils, Climatic change, Plants
Citation
Atahan. P., Heijnis, H., Dodson, J., Grice, K., Le Métayer, P., Taffs, K., Hembrow, S., Woltering, M., & Zawadski, A. (2013). Late quaternary environmental change at Lake McKenzie, Southeast Queensland: evidence from microfossils, biomarkers and stable isotope analysis. Paper presented at the 12th Australian Environmental Isotope Conference, University of Western Australia, Perth, Australia, 10th-12th July 2013.