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Lake evolution in a semi-arid montane environment: response to catchment change and hydroclimatic variation

Research output: Contribution to journalJournal article

Published

  • H. Lamb
  • N. Roberts
  • M. Leng
  • P. Barker
  • A. Benkaddour
  • S. van der Kaars
Journal publication date03/1999
JournalJournal of Paleolimnology
Journal number3
Volume21
Number of pages19
Pages325-343
Original languageEnglish

Abstract

Pollen, geochemical and sedimentological data from Sidi Ali, a montane Moroccan lake, provide a 7000 yr record of changes in climate, catchment vegetation and soil erosion intensity. Diatoms, non-silicious algae, macrophyte fossils and ostracods from the same core record the dynamics of the lake ecosystem. Oxygen isotope and trace-element ratios of benthic ostracods appear to be relatively insensitive to climatic variation in this open lake with low water-residence time, but diatom plankton / periphyton (P/L) ratios show lake-level variations that are probably climate controlled. At least two superimposed processes are recorded, but at different timescales: catchment vegetation and soils show long-term changes due to climate and human impact, whereas P/L ratios suggest century-scale oscillations in lake depth. The timing of changes in algal and macrophyte productivity and carbon cycling within the lake broadly corresponds to changes in terrestrial vegetation, suggesting either that lake nutrient status is linked to catchment vegetation and soils, or that both were influenced by climate. The lack of a sensitive and independent (non-biological) climate proxy makes it more difficult to assess the lake''s ecological response to short-term climate variation. Overall, the lake''s evolution has been influenced both by catchment-mediated nutrient flux and by changes in water balance, thus having characteristics in common with both temperate and arid zone lakes.

Bibliographic note

Mar Lake evolution in a semi-arid montane environment: response to catchment change and hydroclimatic variation Times Cited: 16