Late Quaternary climatic and environmental history of
Institute für Baltic Sea Research Warnemünde (IOW), Germany
University Braunschweig, Germany
University Jena, Germany
Institute for Lake Research, Langenargen, Germany
André Lotter, Oliver Heiri
Utrecht University, The Netherlands
Hydrobiological Institute, Ohrid, Macedonia
Institute of Hydrometeorolgy, Tirana, Albania
Deutscher Akademischer Austausch Dienst (DAAD)
Deutsche Forschungsgemeinschaft (DFG)
Lake Ohrid is located at the Macedonian/Albanian
border between 40°54' and 41°10' N. With a length of c. 30 km
and a width of c. 15 km, the lake surface area measures c. 360
km2, two thirds of which belong to Macedonia and one third, the
southwestern part of the lake, to Albania. The bathymetric maps
existing from the lake show a maximum water depth of almost 300
m. More than 200 endemic species reveal the uniqueness of Lake
Ohrid. This great number of endemic species, mainly formed by
invertebrates and algae, but also by some fishes, indicates that
the overall environmental conditions have been stable over a long
period. Biological and biogeographical studies suggest that the
origin of Lake Ohrid dates back to Early Quaternary or Pliocene times,
about one to five million years ago. Despite the knowledge about the immense
age of the lake, investigations of its sedimentary record in order
to reconstruct the regional climatic and environmental history
full size map
Map of Albania and Macedonia,
indicating the location of Lake Ohrid. The inlet shows a satellite image
of Lake Ohrid.
Main objectives of the
international research project at Lake Ohrid are to
understand regional differences in sedimentation rates
and sediment composition, to reconstruct its Late Quaternary
history in relation to that of the central and eastern
Mediterranean region, and to investigate its potential
for paleoenvironmental reconstructions down to the Tertiary.
Surface sediment coring at Lake Ohrid in spring 2004.
A shallow seismic survey was carried out
on Lake Ohrid in spring 2004 in order to evaluate representative coring
locations for future work. First results evidence that the sediments of
Lake Ohrid are highly affected by mass movement processes. These processes
at least partly were triggered by neotectonic activity, which is suggested
by distinct thrusts and folds occurring in the lake sediments. Slumps,
debris flows and turbidites are common along the lake slopes, but also
occur in parts of the lake center. Other areas of the central lake, however,
exhibit obviously undisturbed sediment sequences ideal for recovering
continuous sediment records. In addition, hiatuses associated with the
mass movement events in some slope areas excavated relatively old sediments
so close to the surface that they may be reached with conventional light coring technique.
During a first coring campaign in March/April 2005 sediment sequences of up to ten meter were recovered.
According to first readiocarbon dates from the longest core it obviously penetrated back deeply into the
last glacial period. Furthermore, a transect of short cores crossing the lake from north to south has been
correlated based on core descriptions and first sedimentological results. The data reflect changes in
subrecent sedimention rates, with the by far highest sediment input occurring from the south and being
predominantly deposited close to the lake shore.
seismic profile from Lake Ohrid
full size seismics
Part of a shallow seismic profile from Lake Ohrid, illustrating
numerous mass movement processes along the slopes, as well as
thrusts and faults which pervade the sediments.
The research groups currently working on Lake Ohrid were brought together during an international
workshop held at the University Leipzig in Dec. 2005. On this workshop, which was financially
supported by the German Academic Exchange Service (Deutscher Akademischer Austausch Dienst, DAAD),
24 participants from 7 countries summarized the existing results from hydrological, biological and
geological investigations at Lake Ohrid, and discussed the perspectives for joint future work.
It was agreed that Lake Ohrid has a great potential to supply important information on the long-term climatic,
tectonic and volcanic history in the eastern Mediterranian region. Applications for a deep drilling operation
to recover the entire lake sediment record, for instance wihin the scope of the
International Continental Scientific Drilling Program (ICDP), however, require additional site survey work
that involves (i) studies of the processes of modern lake sediment formation,
(ii) geomorpholocal research in lake catchment, (iii) additional shallow seimic and first deep seismic
investigations of the lake sediments, and (iv) additional shallow coring and complex investigations of the core material.
Participants on the international "Lake Ohrid Workshop"
held at the University Leipzig in Dec. 2005