Abstract
Lake Prespa, in the Balkans, contains an important palaeo-archive in a key location for understanding Quaternary climate variability in the transition between Mediterranean and central European climate zones. Previous palaeoenvironmental research on sediment cores indicates that the lake is highly sensitive to climate change and that diatoms are likely to be strong palaeohydrological proxies. Here, we present new results from diatom analysis of a ca. 91 ka sequence, core Co1215, which spans the time from the end of the last interglacial to the present. Fluctuations in the diatom data were driven primarily by changes in lake level, as a function of shifts in moisture availability. Warmer interglacial (MIS 5, MIS 1) and interstadial (MIS 3) phases exhibit higher lake levels in spite of enhanced evaporative concentration, underlining the importance of changes in precipitation regimes over time. Low lake levels during glacial phases indicate extreme aridity, common to all Mediterranean lakes. Evidence for fluctuations in trophic status is linked, in part, to lake-level change, but also reflects nutrient enrichment from catchment processes. MIS 5a is characterized by the highest lake productivity in the sequence, but low lake levels, which are ascribed primarily to very low precipitation. On a suborbital timescale, the diatoms provide evidence for correlation to the millennial-scale variability recorded in the Greenland oxygen isotope records and clearly reflect the impact of the Heinrich H6, H5 and H3-1 ice-rafting events, suggesting the dominant influence of North Atlantic forcing in this region. Although the highest-amplitude shift in the diatom assemblages occurs during the time of H4 (40-38 ka), it may be superimposed upon the impact of the 39.28 cal ka BP Campanian Ignimbrite volcanic eruption. Diatoms from Lake Prespa core Co1215 display the first strong evidence for the impact of Italian volcanic activity on lacustrine biota in this region. Results emphasize the complexity of diatom response thresholds in different studies across the region. In the case of Lake Prespa, the results highlight the important role of precipitation for maintaining the hydrological balance of the lake, and indirectly, its biodiversity.
| Original language | English |
|---|---|
| Pages (from-to) | 215-231 |
| Number of pages | 17 |
| Journal | Journal of Paleolimnology |
| Volume | 53 |
| Issue number | 2 |
| DOIs | |
| Publication status | Published - Feb 2015 |
Funding
The authors thank the Alexander von Humboldt Foundation for financial support of the project "Reconstruction of past environmental variations in ancient Lake Ohrid, a diatom inferred perspective.'' The project was partly funded by the German Research Foundation (DFG) within the scope of the Project B2 of the Collaborative Research Center 806 "Our Way to Europe." We thank Paul B. Hamilton, Canadian Museum of Nature, Canada, for helpful discussions about palaeolimnology and Mrs. Danijela Mitic Kopanja, Institute of Biology, Faculty of Natural Sciences, Skopje, Macedonia for technical assistance. We also thank our colleagues in the Institute of Geology and Mineralogy and the Seminar of Geography and Education (University of Cologne) for help in the field and in the lab. We are grateful to Dr. Timothy Jones, Lancaster Environment Centre, Lancaster University, UK for providing diatom data from Lake Ioannina core I-08.
Keywords
- Lake Prespa
- Diatoms
- Lake-level change
- Palaeoclimate
- Tephra impact
- Quaternary Heinrich events
- TEPHROSTRATIGRAPHIC RECORD
- NORTHWEST GREECE
- LATE PLEISTOCENE
- IOANNINA BASIN
- KA
- VARIABILITY
- MACEDONIA
- LEVEL
- CYCLE
- ICE
