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Drivers of ecosystem and climate change in tropical West Africa over the past ∼540 000 years

Miller, Charlotte S.; Gosling, William D.; Kemp, David B.; Coe, Angela L. and Gilmour, Iain (2016). Drivers of ecosystem and climate change in tropical West Africa over the past ∼540 000 years. Journal of Quaternary Science, 31(7) pp. 671–677.

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DOI (Digital Object Identifier) Link: https://doi.org/10.1002/jqs.2893
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Abstract

A paucity of empirical non-marine data means that uncertainty surrounds the impact of climate change on terrestrial ecosystems in tropical regions beyond the last glacial period. The sedimentary fill of the Bosumtwi impact crater (Ghana) provides the longest continuous Quaternary terrestrial archive of environmental change in West Africa, spanning the last ∼1.08 million years. Here we explore the drivers of change in ecosystem and climate in tropical West Africa for the past ∼540 000 years using pollen analysis and the nitrogen isotope composition of bulk organic matter preserved in sediments from Lake Bosumtwi. Variations in grass pollen abundance (0−99%) indicate transitions between grassland and forest. Coeval variations in the nitrogen isotopic composition of organic matter indicate that intervals of grassland expansion coincided with minimum lake levels and low regional moisture availability. The observed changes responded to orbitally paced global climate variations on both glacial–interglacial and shorter timescales. Importantly, the magnitude of ecosystem change revealed by our data exceeds that previously determined from marine records, demonstrating for the first time the high sensitivity of tropical lowland ecosystems to Quaternary climate change.

Item Type: Journal Item
Copyright Holders: 2016 The Authors
ISSN: 0267-8179
Project Funding Details:
Funded Project NameProject IDFunding Body
One million years of environmental change in Africa: implications for hominid evolution (SE-10-187-WG)NE/H525054/1NERC (Natural Environment Research Council)
Astronomical forcing and rapid climate change in the Jurassic. (SE-10-122-AC)NE/I02089X/1NERC (Natural Environment Research Council)
Climate-vegetation dynamics in western tropical Africa: 150,000 years of past environmental change from Lake Bosumtwi (Ghana)NE/G000824/1NERC (Natural Environment Research Council)
Keywords: Lake Bosumtwi; nitrogen isotopes; orbital forcing; palynology; West Africa
Academic Unit/School: Faculty of Science, Technology, Engineering and Mathematics (STEM) > Environment, Earth and Ecosystem Sciences
Faculty of Science, Technology, Engineering and Mathematics (STEM)
Faculty of Science, Technology, Engineering and Mathematics (STEM) > Physical Sciences
Interdisciplinary Research Centre: Centre for Earth, Planetary, Space and Astronomical Research (CEPSAR)
OpenSpace Research Centre (OSRC)
Item ID: 47336
Depositing User: Iain Gilmour
Date Deposited: 19 Sep 2016 10:09
Last Modified: 06 Apr 2017 04:46
URI: http://oro.open.ac.uk/id/eprint/47336
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