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| Titel |
Sediment core fossils in ancient Lake Ohrid: testing for faunal change since the Last Interglacial |
| VerfasserIn |
C. Albrecht, H. Vogel, T. Hauffe, T. Wilke |
| 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 (2010-11-05), S.3435-3446 |
| Datensatznummer |
250005049
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| Publikation (Nr.) |
 copernicus.org/bg-7-3435-2010.pdf |
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| Zusammenfassung |
Ancient Lake Ohrid is probably of early Pleistocene or Pliocene origin and
amongst the few lakes in the world harbouring an outstanding degree of
endemic biodiversity. Although there is a long history of evolutionary
research in Lake Ohrid, particularly on molluscs, a mollusc fossil record
has been missing up to date.
For the first time, gastropod and bivalve fossils are reported from the
basal, calcareous part of a 2.6 m long sediment succession (core Co1200)
from the north-eastern part of Lake Ohrid. Electron spin resonance (ESR)
dating of mollusc shells from the same stratigraphic level yielded an age of
130 ± 28 ka. Lithofacies III sediments, i.e. a stratigraphic
subdivision comprising the basal succession of core Co1200 between
181.5–263 cm, appeared solid, greyish-white, and consisted almost entirely of
silt-sized endogenic calcite (CaCO3>70%) and intact and broken
mollusc shells. Here we compare the faunal composition of the
thanatocoenosis with recent mollusc associations in Lake Ohrid. A total of
13 mollusc species (9 gastropod and 4 bivalve species) could be identified
within Lithofacies III sediments. The value of sediment core fossils for
reconstructing palaeoenvironmental settings was evaluated and the agreement
between sediment and palaeontological proxies was tested.
The study also aims at investigating major faunal changes since the Last
Interglacial and searching for signs of extinction events.
The combined findings of the ecological study and the sediment
characteristics suggest deposition in a shallow water environment during the
Last Interglacial. The fossil fauna exclusively included species also found
in the present fauna, i.e. no extinction events are evident for this site
since the Last Interglacial. The thanatocoenosis showed the highest
similarity with recent Intermediate Layer (5–25 m water depth) mollusc
assemblages. The demonstrated existence of a mollusc fossil record in Lake
Ohrid sediment cores also has great significance for future deep drilling
projects. It can be hoped that a more far reaching mollusc fossil record
will then be obtained, enabling insight into the early evolutionary history
of Lake Ohrid. |
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