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| Titel |
Palaeolimnological reconstructions of mid-late Holocene climate change from South Georgia |
| VerfasserIn |
Wim Van Nieuwenhuyze, Stephen J. Roberts, Dominic A. Hodgson, Elie Verleyen, Mieke Sterken, Koen Sabbe, Wim Vyverman |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250099154
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| Publikation (Nr.) |
 EGU/EGU2014-14906.pdf |
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| Zusammenfassung |
| South Georgia’s position within the Polar Frontal Zone, the core belt of the Southern
Hemisphere Westerly Winds, and between Antarctica and the mid-latitudes makes it a key
location for studying the main drivers of past and present-day climate variability. We
undertook multi-proxy analyses, including fossil diatom, pigment and μ-XRF analysis, of
lake and peat cores from two sites: Annenkov Island, on the southern side of South Georgia,
and Prince Olav Harbour on the northern coast of South Georgia to determine: 1) which
proxies were most suitable for reconstructing Holocene palaeoclimatic change; 2) whether
the climate change signals from these proxies were related to natural lake development,
local catchment processes such as changes in ice extent, or regional-global scale
climatic change. Deglaciation at both sites was completed by c. 7800 cal. yr. B.P. Low
nutrient/low productivity environments, which persisted within lakes at both locations
until c. 3500 cal. yr. B.P., are indicative of the relatively slow development of lake
ecosystems following deglaciation, and suggest high altitude glaciers or persistent
ice-cover remained in both catchments well into the mid Holocene. In contrast, the late
Holocene (c. 3500 yr to present) was characterized by initially higher, and then highly
variable within-lake biological productivity. On Annenkov Island, the late Holocene
diatom composition in Fan Lake was dominated by a single species (Cyclotella
stelligera), and we have identified four major phases of increased catchment disturbance
(represented by Fragilaria capucina peaks in diatom data), some of which coincide
with more numerous meltwater input events (identified from Ti and Sr peaks in
μ-XRF data). In this poster we examine the links between these meltwater events,
results from other proxies, and changes in the climate of the sub-Antarctic region. |
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