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

Abstract

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 longterm 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.

The 4.2 ka BP Event in the Mediterranean region: an overview

“…3). This can be explained by the effect of higher residence time and more dampened isotopic composition of the lake water at Lake Ohrid due to its large recharge by karst springs (more than 50 %; Wagner et al, 2017) in comparison to Lake Prespa (Leng et al, 2010a). This renders the latter much more sensitive to hydrological changes, as demonstrated by its dramatic lowering of lake-level changes in recent years (van der Schriek and Giannakopoulos, 2017).…”

“…However, long-term, astronomically driven changes in insolation produced changes in temperature (Marcott et al, 2013, but see also Marsicek et al, 2018), associated with a progressive southward shift of the Intertropical Convergence Zone (ITCZ) and a weakening of Northern Hemisphere summer monsoon systems (e.g., Wright et al, 1993;Fleitmann et al, 2003;Braconnot et al, 2007). A number of short, multidecadal-to centennial-scale climatic events, the origin of which often remains unclear, are superimposed over this long-term trend (e.g., Denton, and Karlén, 1973;Bond et al, 1997;Mayewski et al, 2004;Wanner et al, 2011). At the regional-to-global scale, some events appear synchronous and linked to specific changes in circulation patterns (e.g., Trouet et al, 2009;Dermody et al, 2012;Zanchetta et al, 2014).…”

Pollen-based temperature and precipitation changes in the Ohrid Basin (western Balkans) between 160 and 70 ka

“…The area is rich in extant Quaternary lakes and palaeolakes, with sediment records providing essential information on past vegetation and climate changes going back hundreds of thousands of years, such as Lake Ohrid (Albania and FYROM; e.g. Lézine et al, 2010;Sinopoli et al, 2018;Wagner et al, 2017), Lake Prespa (Albania, FYROM and Greece;Panagiotopoulos et al, 2014), Ioannina (west Greece; Tzedakis et al, 2003), Tenaghi Philippon (north-east Greece; Milner et al, 2016) and Kopais (south-east Greece; Tzedakis, 1999;Okuda et al, 2001). Despite the richness in long palaeoenvironmental archives, quantitative palaeoclimatic reconstructions have been rarely attempted or cover relatively short periods.…”

“…To discuss the climate signal at a more global scale, we compare our results to available pollen-based reconstructions from northern Europe and the Mediterranean, and to marine and terrestrial proxies from the Mediterranean and the Northern Hemisphere (e.g. De Abreu et al, 2003;Drysdale et al, 2005;NGRIP Members, 2004;Lisiecki and Raymo, 2005;Martrat et al, 2004;Regattieri et al, 2014Regattieri et al, , 2017Sánchez-Goñi et al, 1999;Wang et al, 2010).…”

Towards a phylogeny ofCyclops(Copepoda): (in)congruences among morphology, molecules and zoogeography

“…This would be in agreement with the ancient origin of the deep and oligotrophic L. Ohrid, where C. ochridanus lives. Based on a comprehensive overview of the geological and biological data, Wagner et al () concluded that L. Ohrid had been de novo established from springs and rivers in the Early Pleistocene (1.3 − 1.9 Mya) (for alternative hypotheses, see Albrecht & Wilke, ). Phylogenetic relatedness of C. ochridanus with C. laevis (Central Italy, oligotrophic caldera lakes), C. mongolensis (North Mongolia, Khövsgöl; deep and ancient, ultraoligotrophic lake), C. glacialis (Western Mongolia; oligotrophic lakes) and C. gracilipes (deep oligotrophic lakes in Altay and a smaller lake in Sayan) seems to be also supported by the similarity of the water bodies where these species live.…”