A 700-year record on the effects of climate and human impact on the southern cape coast inferred from lake sediments of eilandvlei, wilderness embayment, south africa
The southern Cape coast, outh frica, is sensitive to climate fluctuations as it is influenced by different atmospheric and oceanic circulation systems. Palaeoecological evidence of Holocene climate variations in this region is presently limited. Here, we present a lake sediment record spanning appro...
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Published in | Geografiska annaler. Series A, Physical geography Vol. 95; no. 4; pp. 345 - 360 |
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Main Authors | , , , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
Taylor & Francis
01.12.2013
Blackwell Publishing Ltd Swedish Society for Anthropology and Geography |
Subjects | |
Online Access | Get full text |
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Summary: | The southern Cape coast, outh frica, is sensitive to climate fluctuations as it is influenced by different atmospheric and oceanic circulation systems. Palaeoecological evidence of Holocene climate variations in this region is presently limited. Here, we present a lake sediment record spanning approximately the last 670 years from ilandvlei, a brackish coastal lake situated mid-way between Cape Town and Port lizabeth. The results from geochemical and sedimentological analyses point to an increase in minerogenic sediment input from the catchment starting around ad 1400. Changes in the seasonal distribution of rainfall during the Little Ice Age may have altered river discharge and increased erosion rates and fluvial sediment transport in pre-colonial times. A rising mean lake level, possibly associated with an altered water balance or relative sea-level rise, may offer an explanation for the deposition of finer sediments. After ad 1450, reduced burial flux of elements associated with autochthonous sediment formation may have resulted from ecological changes in ilandvlei. Enhanced sedimentation rates, increasing carbon, nitrogen, phosphorous and biogenic silica concentrations, as well as high concentrations of proxies for allochthonous sediment input (e.g. aluminium, titanium, zirconium) point to increasing sediment and nutrient flux into ilandvlei from the late nineteenth century onwards. The most likely factor involved in these recent changes is land-use change and other forms of human impact. |
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Bibliography: | International Bureau, Bundesministerium für Bildung und Forschung (BMBF, Germany) - No. SUA 09/10 istex:A2FC77E33CE07C69A95023926580580917873544 ArticleID:GEOA12015 ark:/67375/WNG-B3MWQD86-M National Research Foundation (NRF, South Africa) - No. UID 72083 SANParks Scientific Services, Rondevlei ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0435-3676 1468-0459 |
DOI: | 10.1111/geoa.12015 |