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Titel |
Stratigraphic analysis of lake level fluctuations in Lake Ohrid: an integration of high resolution hydro-acoustic data and sediment cores |
VerfasserIn |
K. Lindhorst, H. Vogel, S. Krastel, B. Wagner, A. Hilgers, A. Zander, T. Schwenk, M. Wessels, G. Daut |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1726-4170
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Digitales Dokument |
URL |
Erschienen |
In: Biogeosciences ; 7, no. 11 ; Nr. 7, no. 11 (2010-11-10), S.3531-3548 |
Datensatznummer |
250005056
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Publikation (Nr.) |
copernicus.org/bg-7-3531-2010.pdf |
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Zusammenfassung |
Ancient Lake Ohrid is a steep-sided, oligotrophic, karst lake that was
tectonically formed most likely within the Pliocene and often referred to as
a hotspot of endemic biodiversity. This study aims on tracing significant
lake level fluctuations at Lake Ohrid using high-resolution acoustic data in
combination with lithological, geochemical, and chronological information
from two sediment cores recovered from sub-aquatic terrace levels at ca. 32 and 60 m water depth. According to our data, significant lake level
fluctuations with prominent lowstands of ca. 60 and 35 m below the present
water level occurred during Marine Isotope Stage (MIS) 6 and MIS 5,
respectively. The effect of these lowstands on biodiversity in most coastal
parts of the lake is negligible, due to only small changes in lake surface
area, coastline, and habitat. In contrast, biodiversity in shallower areas
was more severely affected due to disconnection of today sub-lacustrine
springs from the main water body. Multichannel seismic data from deeper
parts of the lake clearly image several clinoform structures stacked on top
of each other. These stacked clinoforms indicate significantly lower lake
levels prior to MIS 6 and a stepwise rise of water level with intermittent
stillstands since its existence as water-filled body, which might have
caused enhanced expansion of endemic species within Lake Ohrid. |
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