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

Bastian Reinwarth, Sarah Franz, Jussi Baade, Torsten Haberzettl, Thomas Kasper, Gerhard Daut, Jörg Helmschrot, Kelly L. Kirsten, Lynne J. Quick, Michael E. Meadows, Roland Mäusbacher

Research output: Contribution to journalArticlepeer-review

21 Citations (Scopus)

Abstract

The southern Cape coast, South Africa, 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 Eilandvlei, a brackish coastal lake situated mid‐way between Cape Town and Port Elizabeth. 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 Eilandvlei. 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 Eilandvlei 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.
Original languageEnglish
Pages (from-to)345-360
Number of pages16
JournalGeografiska Annaler: Series A, Physical Geography
Volume95
Issue number4
DOIs
Publication statusPublished - 2013
Externally publishedYes

Funder

Financial support from the International Bureau, Bundesministerium für Bildung und Forschung (BMBF, Germany, grant SUA-09/10), the National Research Foundation (NRF, South Africa, grant UID-72083) and participating universities as well as logistic support from SANParks Scientific Services, Rondevlei, is gratefully acknowledged.

Keywords

  • South Africa
  • southern Cape
  • coastal lake
  • lake sediments
  • geochemistry
  • sedimentology
  • Little Ice Age
  • human impact

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