Articles | Volume 14, issue 8
https://doi.org/10.5194/bg-14-2033-2017
https://doi.org/10.5194/bg-14-2033-2017
Research article
 | 
20 Apr 2017
Research article |  | 20 Apr 2017

The environmental and evolutionary history of Lake Ohrid (FYROM/Albania): interim results from the SCOPSCO deep drilling project

Bernd Wagner, Thomas Wilke, Alexander Francke, Christian Albrecht, Henrike Baumgarten, Adele Bertini, Nathalie Combourieu-Nebout, Aleksandra Cvetkoska, Michele D'Addabbo, Timme H. Donders, Kirstin Föller, Biagio Giaccio, Andon Grazhdani, Torsten Hauffe, Jens Holtvoeth, Sebastien Joannin, Elena Jovanovska, Janna Just, Katerina Kouli, Andreas Koutsodendris, Sebastian Krastel, Jack H. Lacey, Niklas Leicher, Melanie J. Leng, Zlatko Levkov, Katja Lindhorst, Alessia Masi, Anna M. Mercuri, Sebastien Nomade, Norbert Nowaczyk, Konstantinos Panagiotopoulos, Odile Peyron, Jane M. Reed, Eleonora Regattieri, Laura Sadori, Leonardo Sagnotti, Björn Stelbrink, Roberto Sulpizio, Slavica Tofilovska, Paola Torri, Hendrik Vogel, Thomas Wagner, Friederike Wagner-Cremer, George A. Wolff, Thomas Wonik, Giovanni Zanchetta, and Xiaosen S. Zhang

Abstract. This study reviews and synthesises existing information generated within the SCOPSCO (Scientific Collaboration on Past Speciation Conditions in Lake Ohrid) deep drilling project. The four main aims of the project are to infer (i) the age and origin of Lake Ohrid (Former Yugoslav Republic of Macedonia/Republic of Albania), (ii) its regional seismotectonic history, (iii) volcanic activity and climate change in the central northern Mediterranean region, and (iv) the influence of major geological events on the evolution of its endemic species. The Ohrid basin formed by transtension during the Miocene, opened during the Pliocene and Pleistocene, and the lake established de novo in the still relatively narrow valley between 1.9 and 1.3 Ma. The lake history is recorded in a 584 m long sediment sequence, which was recovered within the framework of the International Continental Scientific Drilling Program (ICDP) from the central part (DEEP site) of the lake in spring 2013. To date, 54 tephra and cryptotephra horizons have been found in the upper 460 m of this sequence. Tephrochronology and tuning biogeochemical proxy data to orbital parameters revealed that the upper 247.8 m represent the last 637 kyr. The multi-proxy data set covering these 637 kyr indicates long-term variability. Some proxies show a change from generally cooler and wetter to drier and warmer glacial and interglacial periods around 300 ka. Short-term environmental change caused, for example, by tephra deposition or the climatic impact of millennial-scale Dansgaard–Oeschger and Heinrich events are superimposed on the long-term trends. Evolutionary studies on the extant fauna indicate that Lake Ohrid was not a refugial area for regional freshwater animals. This differs from the surrounding catchment, where the mountainous setting with relatively high water availability provided a refuge for temperate and montane trees during the relatively cold and dry glacial periods. Although Lake Ohrid experienced significant environmental change over the last 637 kyr, preliminary molecular data from extant microgastropod species do not indicate significant changes in diversification rate during this period. The reasons for this constant rate remain largely unknown, but a possible lack of environmentally induced extinction events in Lake Ohrid and/or the high resilience of the ecosystems may have played a role.

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Short summary
Lake Ohrid is considered to be the oldest existing lake in Europe. Moreover, it has a very high degree of endemic biodiversity. During a drilling campaign at Lake Ohrid in 2013, a 569 m long sediment sequence was recovered from Lake Ohrid. The ongoing studies of this record provide first important information on the environmental and evolutionary history of the lake and the reasons for its high endimic biodiversity.
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