The onset of deglaciation in the Larsemann Hills, Eastern Antarctica

Burgess, J. S.; Spate, Andy; Shevlin, J.

doi:10.1017/s095410209400074x

Cited by 71 publications

(53 citation statements)

References 6 publications

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“…In addition, radiocarbon and TL dating of lacustrine sediments in Progress Lake and Lake Reid (Fig. 1) have shown that parts of Broknes have been ice-free since at least 40 000 yr BP (Burgess et al, 1994;Hodgson et al, 2001a), making it unlikely that continental ice melted in the Heart Lake basin during the Holocene. More likely, the till zone in Heart Lake is derived from a readvance or iceberg discharge from the Dålk Glacier (East of Heart Lake) and the inwash of subglacial tills from the margins of this glacier, which may have extended past the northern end of Broknes at this time.…”

Section: Discussionmentioning

confidence: 99%

Late Quaternary deglaciation and climate history of the Larsemann Hills (East Antarctica)

Verleyen

Hodgson

Sabbe

et al. 2004

J Quaternary Science

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The Late Quaternary climate history of the Larsemann Hills has been reconstructed using siliceous microfossils (diatoms, chrysophytes and silicoflagellates) in sediment cores extracted from three isolation lakes. Results show that the western peninsula, Stornes, and offshore islands were ice-covered between 30 000 yr BP and 13 500 cal. yr BP. From 13 500 cal. yr BP (shortly after the Antarctic Cold Reversal) the coastal lakes of the Larsemann Hills were deglaciated and biogenic sedimentation commenced. Between 13 500 and 11 500 cal. yr BP conditions were warmer and wetter than during the preceding glacial period, but still colder than today. From 11 500 to 9500 cal. yr BP there is evidence for wet and warm conditions, which probably is related to the early Holocene climate optimum, recorded in Antarctic ice cores. Between 9500 and 7400 cal. yr BP dry and cold conditions are inferred from high lake-water salinities, and low water levels and an extended duration of nearshore sea-ice. A second climate optimum occurred between 7400 and 5230 cal. yr BP when stratified, open water conditions during spring and summer characterised the marine coast of Prydz Bay. From 5230 until 2750 cal. yr BP sea-ice duration in Prydz Bay increased, with conditions similar to the present day. A short return to stratified, open water conditions and a reduction in nearshore winter sea-ice extent is evident between 2750 and 2200 cal. yr BP. Simultaneously, reconstructions of lake water depth and salinity suggests relatively humid and warm conditions on land between 3000 and 2000 cal. yr BP, which corresponds to a Holocene Hypsithermal reported elsewhere in Antarctica. Finally, dry conditions are recorded around 2000, between 760 and 690, and between 280 and 140 cal. yr BP. These data are consistent with ice-core records from Antarctica and support the hypothesis that lacustrine and marine sediments on land can be used to evaluate the effect of long-term climate change on the terrestrial environment.

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Section: Discussionmentioning

confidence: 99%

Late Quaternary deglaciation and climate history of the Larsemann Hills (East Antarctica)

Verleyen

Hodgson

Sabbe

et al. 2004

J Quaternary Science

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“…Such lakes might prove useful sites to study the degree to which organisms can adapt to permanently cold, nutrientlimited environments over longer time scales than have been available to other Antarctic lakes. However, the recent reports of 'oases' that appear to have been ice-free for > 20 000 years (Burgess et al, 1994), and yet have very low lake species diversity, raise doubts that widespread significant adaptation has occurred, even over extended time scales.…”

Section: Discussionmentioning

confidence: 99%

Microbial diversity and function in Antarctic freshwater ecosystems

Ellis‐Evans

1996

Biodivers Conserv

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Freshwater lakes occur through much of Antarctica and are characterized by short food chains dominated by microbes. Comparatively few studies have been made of continental freshwater lakes until recently, with the main emphasis being on the less extreme maritime Antarctic lakes. The wide range of trophic status seen at the northern extremes of the maritime Antarctic reduces markedly further south, but a wide range of micro-organisms occur throughout the latitudinal range. Information on seasonal and spatial patterns of microbial activity for freshwater lakes demonstrate rapid changes in community composition at certain times of year despite constant low temperatures. Benthic communities of cyanobacteria and bacteria are a feature of most lakes and are involved in a wide range of geochemical cycling. There is a need for more detailed taxonomic information on most groups and considerable potential for molecular studies.

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“…Continued. May 20141999, Lyons et al 2001, Hodgson et al 2004), Larseman Hills (Burgess et al 1994), and Schirmacher Oasis (Bormann and Fritzsche 1995 (Hall et al 2000, Hendy 2000. Thus the soils in the eastern end of the Taylor Valley are young (;24 kyr and less), while those in the western part of the valley are much older (;75-130 kyr), indicating that even at the last glacial maximum the Antarctic terrestrial environment was not completely covered by ice.…”

Section: Climate Since the Last Glacial Maximummentioning

confidence: 99%

The spatial structure of Antarctic biodiversity

Convey

Chown

Clarke

et al. 2014

Ecological Monographs

317

296

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Patterns of environmental spatial structure lie at the heart of the most fundamental and familiar patterns of diversity on Earth. Antarctica contains some of the strongest environmental gradients on the planet and therefore provides an ideal study ground to test hypotheses on the relevance of environmental variability for biodiversity. To answer the pivotal question, “How does spatial variation in physical and biological environmental properties across the Antarctic drive biodiversity?” we have synthesized current knowledge on environmental variability across terrestrial, freshwater, and marine Antarctic biomes and related this to the observed biotic patterns. The most important physical driver of Antarctic terrestrial communities is the availability of liquid water, itself driven by solar irradiance intensity. Patterns of biota distribution are further strongly influenced by the historical development of any given location or region, and by geographical barriers. In freshwater ecosystems, free water is also crucial, with further important influences from salinity, nutrient availability, oxygenation, and characteristics of ice cover and extent. In the marine biome there does not appear to be one major driving force, with the exception of the oceanographic boundary of the Polar Front. At smaller spatial scales, ice cover, ice scour, and salinity gradients are clearly important determinants of diversity at habitat and community level. Stochastic and extreme events remain an important driving force in all environments, particularly in the context of local extinction and colonization or recolonization, as well as that of temporal environmental variability. Our synthesis demonstrates that the Antarctic continent and surrounding oceans provide an ideal study ground to develop new biogeographical models, including life history and physiological traits, and to address questions regarding biological responses to environmental variability and change.

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The onset of deglaciation in the Larsemann Hills, Eastern Antarctica

Cited by 71 publications

References 6 publications

Late Quaternary deglaciation and climate history of the Larsemann Hills (East Antarctica)

Late Quaternary deglaciation and climate history of the Larsemann Hills (East Antarctica)

Microbial diversity and function in Antarctic freshwater ecosystems

The spatial structure of Antarctic biodiversity

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