Journal of Paleolimnology

, Volume 48, Issue 2, pp 417–431

Responses of diatoms to the Younger Dryas climatic reversal in a South Carpathian mountain lake (Romania)

  • Krisztina Buczkó
  • Enikő Magyari
  • Thomas Hübener
  • Mihály Braun
  • Miklós Bálint
  • Mónika Tóth
  • André F. Lotter
Original paper

DOI: 10.1007/s10933-012-9618-1

Cite this article as:
Buczkó, K., Magyari, E., Hübener, T. et al. J Paleolimnol (2012) 48: 417. doi:10.1007/s10933-012-9618-1

Abstract

A high-resolution paleolimnological study from Lake Brazi, a small mountain lake in the Southern Carpathian Mountains, Romania, shows distinct diatom responses to late glacial and early Holocene climate change between ca. 15,750 and 10,000 cal year BP. Loss-on-ignition, titanium, sulphur, phosphorus, biogenic silica content, and diatom assemblage composition were used as proxies for past environmental changes. Total epilimnetic phosphorus (TP) concentrations and lakewater pH were reconstructed quantitatively using diatom-TP and pH transfer functions. The most remarkable changes in the aquatic ecosystem were found at ca. 12,870 and 10,400 cal year BP. Whereas the onset of the Younger Dryas (YD) climatic reversal was conspicuous in our record, the beginning of the Holocene was not well marked. Two diatom assemblage zones characterize the YD in Lake Brazi, suggesting a bipartite division of this climatic oscillation. The diatom responses to the YD cooling were (1) a shift from Staurosira venter to Stauroforma exiguiformis dominance; (2) a decrease in overall diatom diversity; (3) a decrease in lake productivity, inferred from DI-TP, organic matter, and biogenic silica content; and (4) a lowering of the DI-pH. Compositional change of the diatom assemblages suggested a sudden shift towards more acidic lake conditions at 12,870 cal year BP, which is interpreted as a response to prolonged ice cover and thus shorter growing seasons and/or enhanced outwash of humic acids from the catchment. Taking into account the chironomid-based inference of only moderate July mean temperature decrease (<1 °C), together with the pollen-inferred regional opening of the forest cover and expansion of steppe-tundra, our data suggest that ecosystem changes in the Southern Carpathians during the YD were likely determined by strong seasonal changes.

Keywords

Diatoms Mountain lake Retezat Mountains Seasonality Transfer function Younger Dryas 

Copyright information

© Springer Science+Business Media B.V. 2012

Authors and Affiliations

  • Krisztina Buczkó
    • 1
  • Enikő Magyari
    • 2
  • Thomas Hübener
    • 3
  • Mihály Braun
    • 4
  • Miklós Bálint
    • 5
    • 6
  • Mónika Tóth
    • 7
  • André F. Lotter
    • 8
  1. 1.Department of BotanyHungarian Natural History MuseumBudapestHungary
  2. 2.HAS-NHMUS Research Group for PaleontologyBudapestHungary
  3. 3.Institute of BiosciencesUniversity of RostockRostockGermany
  4. 4.Department of Inorganic and Analytical ChemistryUniversity of DebrecenDebrecenHungary
  5. 5.Biodiversität und Klima Forschungszentrum Frankfurt am MainFrankfurt am MainGermany
  6. 6.Molecular Biology CenterBabes-Bolyai UniversityClujRomania
  7. 7.Hungarian Academy of SciencesCentre for Ecological Research Balaton Limnological InstituteTihany, Klebelsberg Kuno 3Hungary
  8. 8.Deptartment of Physical Geography, PalaeoecologyUtrecht UniversityUtrechtThe Netherlands