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T9
Lateglacial and Holocene Climate and Environmental Change in the Northeastern
Mediterranean Region: The Diatom Evidence from Lake Dojran (Republic of
Macedonia/Greece)
X.S. Zhang 1 *, J.M. Reed 1 , B. Wagner 2 , A. Francke 2 and Z. Levkov 3
1 Department of Geography, Environment and Earth Sciences, University of Hull, Hull
2 Institute of Geology and Mineralogy, University of Cologne, Cologne, Germany
3 Institute of Biology, Faculty of Natural Sciences, Skopje, Republic of Macedonia
The northeastern Mediterranean region is located on an important boundary between
classic Mediterranean and continental climate zones. In spite of the recent increase in
palaeoclimate research, our understanding of patterns and mechanisms of Late
Quaternary climate change is still poor across the region, with spatial inconsistency in
inferred patterns of change. The southern Balkan Republic of Macedonia varies in climate
between continental-Mediterranean (ancient Lake Ohrid and Lake Prespa in the
southeast) and classic Mediterranean (Lake Dojran in the west). As part of a multi-site
ICDP project which aims to reconstruct Quaternary climate across multiple glacialinterglacial
cycles, this study focuses on limnological response to Lateglacial and
Holocene climate and environmental change from analysis of a 7.17 m core from Lake
Dojran, which is currently a shallow and hypereutrophic lake which has suffered
accelerated impact from water abstraction and anthropogenic nutrient input. The results of
diatom analysis show a shift to the dominance of benthic taxa, including obligate saline
taxa, during the Younger Dryas period, providing the strong evidence for minimum lake
level and enhanced aridity. During the earliest Holocene (corresponding to the Preboreal
period) the low diversity dominance of planktonic Cyclotella ocellata indicates a maximum
lake depth, probably due to meltwater impulse. During the early Holocene a shallower and
eutrophic condition is indicated by the dominance of non-planktonic taxa. During the mid
Holocene the planktonic taxa such as Aulacoseira granulata, Stephanodiscus medius, S.
hantzschii and Cyclostephanos dubius indicate a eutrophic, possibly relatively deep and
turbid condition. In spite of low concentration and high dissolution of diatoms during the
late Holocene, the diatom composition indicates a shallow condition and high nutrient
level. However, in spite of enhanced anthropogenic deforestation, there is no clear
evidence for accelerated nutrient input in the recent past.
Keywords: northeastern Mediterranean; Lake Dojran; diatom; Younger Dryas; Holocene