A Late Glacial to Holocene Record of Environmental Change from Lake Dojran
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EGU Journal Logos (RGB) Open Access Open Access Open Access Advances in Annales Nonlinear Processes Geosciences Geophysicae in Geophysics Open Access Open Access Natural Hazards Natural Hazards and Earth System and Earth System Sciences Sciences Discussions Open Access Open Access Atmospheric Atmospheric Chemistry Chemistry and Physics and Physics Discussions Open Access Open Access Atmospheric Atmospheric Measurement Measurement Techniques Techniques Discussions Open Access Open Access Biogeosciences Biogeosciences Discussions Open Access Open Access Clim. Past, 9, 481–498, 2013 Climate www.clim-past.net/9/481/2013/ Climate doi:10.5194/cp-9-481-2013 of the Past of the Past © Author(s) 2013. CC Attribution 3.0 License. Discussions Open Access Open Access Earth System Earth System Dynamics Dynamics Discussions A Late Glacial to Holocene record of environmental change Open Access Open Access from Lake Dojran (Macedonia, Greece) Geoscientific Geoscientific Instrumentation Instrumentation A. Francke1, B. Wagner1, M. J. Leng2,3, and J. Rethemeyer1 Methods and Methods and 1University of Cologne, Institute for Geology and Mineralogy, Cologne, Germany Data Systems Data Systems 2University of Leicester, Department of Geology, Leicester, LE1 7RH, UK Discussions Open Access 3 Open Access NERC Isotope Geosciences Laboratory, British Geological Survey, Nottingham, NG12 5GG, UK Geoscientific Geoscientific Correspondence to: A. Francke ([email protected]) Model Development Model Development Received: 12 November 2012 – Published in Clim. Past Discuss.: 21 November 2012 Discussions Revised: 31 January 2013 – Accepted: 4 February 2013 – Published: 28 February 2013 Open Access Open Access Hydrology and Hydrology and Abstract. A Late Glacial to Holocene sediment sequence Aufgebauer et al., 2012; PanagiotopoulosEarth System et al., 2012) com- Earth System (Co1260, 717 cm) from Lake Dojran, located at the boarder plicates the reconstruction of climate change in the Balkan of the F.Y.R. of Macedonia and Greece, has been investi- region (Vogel et al., 2010a). AdditionalSciences records with high- Sciences gated to provide information on climate variability in the resolution sedimentary information from this region are Discussions Open Access Balkan region. A robust age-model was established from 13 needed to get a better understanding of LateOpen Access Glacial to radiocarbon ages, and indicates that the base of the sequence Holocene climatic variability and anthropogenic activity and Ocean Science was deposited at ca. 12 500 cal yr BP, when the lake-level their spatial variability.Ocean As shown byScience a comparison of records Discussions was low. Variations in sedimentological (H2O, TOC, CaCO3, from lakes Prespa and Ohrid (Leng et al., 2010; Wagner et al., 18 13 TS, TOC/TN, TOC/TS, grain-size, XRF, δ Ocarb, δ Ccarb, 2010), shallower lakes often react more sensitive to environ- 13 δ Corg) data were linked to hydro-acoustic data and indi- mental change. Hence, we can assume that Lake Dojran with Open Access cate that warmer and more humid climate conditions charac- a maximum water depth < 7 m provides a valuableOpen Access record terised the remaining period of the Younger Dryas until the of climatic change and anthropogenic impact at the Balkan Solid Earth beginning of the Holocene. The Holocene exhibits significant region. Solid Earth environmental variations, including the 8.2 and 4.2 ka cool- Lake Dojran is located at the boarder of the Former Discussions ing events, the Medieval Warm Period and the Little Ice Age. Yugoslav Republic of Macedonia (FYROM) and Greece Human induced erosion processes in the catchment of Lake (Fig. 1). A lake-level lowering of 6 m between 1955 and Dojran intensified after 2800 cal yr BP. 2000 was mainly caused by irrigation and canalisationOpen Access of Open Access the former outlet, River Doiranitis (Griffiths et al., 2002; The Cryosphere Zacharias et al., 2002;The Sotiria Cryosphere and Petkovski, 2004; Manley et Discussions al., 2008). This lake level decrease led to eutrophication and 1 Introduction is well recorded in the chemical, biological and stable isotope data of the surface sediments (Veljanoska-Sarafiloska et al., Although several paleoenvironmental records spanning the 2001; Griffiths et al., 2002). Increasing anthropogenic influ- entire Holocene already exist from the Balkan region (e.g., ence at Lake Dojran from the mid to late Holocene has been Bordon et al., 2009; Wagner et al., 2009; Vogel et al., 2010a; inferred from pollen assemblages in sediment cores recov- Peyron et al., 2011; Panagiotopoulos et al., 2012), some suf- ered close to the lakeshore (Athanasiadis et al., 2000). How- fer from poor radiocarbon chronologies (Wagner et al., 2009; ever, the sediments are poorly dated and there were likely Vogel et al., 2010a), or are inconsistent in terms of spa- variations in the sedimentation rates including major hia- tial variability and short-term climate events (Magny et al., tuses, probably due to significant lake level changes, partic- 2003, 2009; Tzedakis, 2007; Berger and Guilaine, 2009). ularly in the lateral coring locations. Furthermore, significant anthropogenic impact at least since the late Holocene (e.g., Willis, 1994; Wagner et al., 2009; Published by Copernicus Publications on behalf of the European Geosciences Union. 482 A. Francke et al.: A Late Glacial to Holocene record of environmental change from Lake Dojran A 15° Croatia 20° E B Romania 45° Bosnia & N Herzeg. Serbia Adriatic Bulgaria Sea Albania Dojran FYROM 2 Italy FYROM T. P. S. M. M. 1 Co1260 Greece Turkey T. Aegean Ohrid, X. Sea Greece Prespa & Maliq P. K. Ionian Sea 35° 0 100 200km N 0 1 2 km Fig. 1. (A) Locations of Lake Dojran in the northeastern Mediterranean region at the boarder of the Former Yugoslav Republic of Macedonia (FYROM) and Greece. Locations of other paleoclimate records in the region are lakes Ohrid, Prespa, and Maliq, Lake Xinias (X), Lake Kopais (K.), Lago Grande di Monticchio (M.), Lago di Trifoglietti (T.), Lago di Pergusa (P.), Tenaghi Philippon (T.P.), and the Sea of Marmara (S.M.). (B) Satellite image of Lake Dojran with the coring location Co1260 (red square) and the hydro-acoustic profiles. Numbers 1 and 2 mark the hydro-acoustic profiles shown in Fig. 2, the black arrow indicates the position of the former outlet River Doiranitis, and the yellow line shows the border between FYROM and Greece. 2 Site descriptions (612 mm) falls during mild winters (Sotiria and Petkovski, 2004), and dry conditions persist during warm summers. Lake Dojran (Fig. 1, 41◦120 N, 22◦440 E) is considered to In 2004, Lake Dojran had a lake water surface area of 2 be a relict of the Plio-Pleistocene Peonic Lake, which was 40 km with water depths between 3 and 4 m (Sotiria and formed by volcanic and tectonic activities (Cvijic, 1911; Petkovski, 2004). However, there are seasonal and longer- Stojanov and Micevski, 1989). Lake Dojran is located at term progressive changes that affected the surface area 144 m a.s.l. (above sea level) in a carstic depression formed and water depth (cf. Athanasiadis et al., 2000; Manley et by Paleozoic marble intercalated with phylites (Stojanov and al., 2008). Thermal stratification occurs during the summer Micevski, 1989). The lake catchment predominantly com- months (Zacharias et al., 2002), and it is presumed that lake prises Paleozoic mica gneiss, muscovite-gneiss and amphi- water mixing occurs during winter, similar to Lake Prespa bolite, Tertiary volcanic and volcanic-sedimentary rocks, (Matzinger et al., 2006). Due to its location in the carstic and Quaternary alluvial and limnic sediments (Stojanov and depression, Lake Dojran is bicarbonate- and chloride-rich, Micevski, 1989; Sotiria and Petkovski, 2004). Only 18 % of alkaline and productive (Stankovic, 1931; Griffiths et al., the total catchment area of 275 km2 exceeds an elevation of 2002). Today, the littoral area of the lake comprises a fringe 500 m a.s.l. The high-elevated regions are in the northeast of up to 30 m wide reed beds. of Lake Dojran, where the Belisca Mountain range is up to 1870 m a.s.l. high (Sotiria and Petkovski, 2004). Small rivers, creeks and groundwater drain the catchment area and feed 3 Material and methods Lake Dojran, particularly during winter and spring (Griffiths et al., 2002; Sotiria and Petkovski, 2004). The former outlet 3.1 Fieldwork of Lake Dojran, River Doiranitis, which connected the lake to the Axios/Vardar River, is located some metres above the Fieldwork at Lake Dojran was carried out in June 2011. A present lake-level. Current water loss from Lake Dojran is hydro-acoustic survey (Innomar SES-2000 compact, 10 kHz) due to evaporation and probably to groundwater outflow. on the Macedonian part of the lake (Fig. 1) was used to The climate at Lake Dojran is influenced by the Mediter- provide more detailed information on the lake bathymetry ranean Sea via the connection of the Thessaloniki Plain, and the sediment architecture. At coring location Co1260 continental influences and local morphology, leading to a (41◦11.7030 N, 22◦44.5730 E) undisturbed, horizontal bed- warmer climate with less days with frost compared to other ded sediments and a water depth of ∼ 6.6 m were observed regions in Macedonia (Sotiria and Petkovski, 2004). The (Fig. 2). Core Co1260 was recovered from a floating plat- mean annual air temperature was +14.3 ◦C between 1961 and form using a gravity corer for undisturbed surface sedi- 2000, with monthly average summer and winter temperatures ments and a percussion piston corer for deeper sediments of +26.1 and +3.7 ◦C, respectively (Sotiria and Petkovski, (both UWITEC Co., Austria). After recovery, the overlap- 2004). The highest proportion of the annual precipitation ping 300 cm long sediment cores were cut into (and up to) Clim. Past, 9, 481–498, 2013 www.clim-past.net/9/481/2013/ A. Francke et al.: A Late Glacial to Holocene record of environmental change from Lake Dojran 483 Fig.