Advances in Oceanography and Limnology, 2016; 7(2): 206-219 ARTICLE DOI: 10.4081/aiol.2016.6217 This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License (CC BY-NC 4.0). The Eemian/Early Vistulian development of the Solniki paleolake (north-eastern Poland) as shown by subfossil Cladocera Monika Magdalena Niska* Institute of Geography and Regional Study, Pomeranian University in Słupsk, Partyzantów 27, 76-200 Słupsk, Poland *Corresponding author: [email protected] ABSTRACT This work presents results of a paleolimnological study focussed on subfossil Cladocera analysis and on different aspects of the evolution of the Solniki paleolake during the Eemian/Early Vistulian period. The study aimed at the reconstruction of the long-term dy- namics of this paleoecosystem and at defining the conditions (e.g., water level, trophic status and water temperature) of the ancient lake. Paleolacustrine deposits of ca. 10 m thickness were discovered at Solniki during cartographic works for the Trześcianka sheet of the Detailed Geological Map of Poland. This archives recorded one full-interglacial sequence (Eemian Interglacial), one interstadial warming (Brørup) and two stadial coolings (Herning and Rederstall) stages, which were confirmed by palynological analyses. The sub- fossil Cladocera fauna from the Solniki paleolake consisted in 17 species belonging to the families Bosminidae, Chydoridae, Sididae and Daphniidae. Littoral species were dominant (52%), the most frequent of which were Alonaonly affinis and Camptocercus rectirostris. The most abundance pelagic species were Eubosmina coregoni and Bosmina longirostris. The sediment species composition was quite similar to that of contemporary Central European lakes. The early and the late stages of Eemian Interglacial were likely the most favourable periods for the Cladocera development in the paleolake, in relation to higher water level, moderate water temperature and the mesotrophic state of water. A further ecologically favourable period was the Brørupuse Interstadial. The highest species richness, abun- dance, and diversity during the whole paleolake existence were recorded during these three periods. Surprisingly, the middle of the Middle Eemian Interglacial climate optimum appeared as an unfavourable period for the Cladocera growth as it was associated with decreasing water level and pronounced climate fluctuations. This sequence was also recorded by other studies of Eemian lakes in Central Europe. Key words: Cladocera analysis; Eemian/Early Vistulian; NE Poland. Received: July 2016. Accepted: December 2016. Numerous localities with lacustrine sediments from INTRODUCTION commercialthe Eemian Interglacial (MIS 5e) are present in Europe. The sediments that accumulate year by year in natural Up to date, more than 300 sediment profiles from the lakes are a key source of information on past environmental Eemian Interglacial have been discovered in Poland and and climate changes and the most valuable sediment analysed for pollens (Granoszewski, 2003; Bruj and archive are those spanningNon over longer time periods Krupiński, 2001; Mamakowa, 1989; Dobracka and Winter (Cohen, 2003). Sediments from contemporary temperate 2001; Kupryjanowicz, 2008, Kupryjanowicz et al. 2004). lake allow to track environment changes that have taken The analyses of other proxies (e.g., lithology, stable iso- place after the end of the last glaciation (Szeroczyńska and topes, geochemistry, animal and plant remains, pigments) Zawisza 2007, Nevalainen, 2013). However, information are still less frequent in sediments of Eemian age on earlier interglacial stages is precluded. In addition, lake (Robertsson, 2000; Mirosław-Grabowska, 2005; Gan- changes during the Holocene were the result of the combi- douin, 2007; Nazarova, 2012), though each one is able to nation between natural processes and increasing human ac- add precious information to complete the picture of the tivities (Cheddadi, 1998). The effects of natural and human past ecosystem. driven processes is difficult to be discriminated. Over 80 Eemian Interglacial sites have been discov- The analyses of sediments from ancient paleolakes, ered in north-eastern Poland (Kupryjanowicz, 2008). Nu- which existed and disappeared from the landscape only merous Eemian paleolakes of the northern Podlasie under the influence of natural processes, provided oppor- indicate that during the Eemian Interglacial, a sort of lake tunity to study a period spanning across glaciation, the district existed in this region (Kupryjanowicz, 2008). Late Saalian (syn. Wartanian, 160-140 ka), a warming pe- Nevertheless archives spanning the Eemian Interglacial riod, Eemian Interglacial, and another cool period, Early and the Vistulian Glaciation are rare, especially in areas Vistulian Glaciation. which have been influence by the Vistulian ice-sheet. Eemian/Vistulian development of a Polish paleolake 207 Solniki is one of two northern Podlasie sites which Miroslaw-Grabowska, 2015). This paper presents for the play a key role in the reconstruction of vegetation succes- first time full results of subfossil Cladocera analysis for sion and climate changes over the last interglacial-glacial the entire profile (Eemian Interglacial and Early Vistulian cycle, from the final stage of the Wartanian Glaciation part - 3.0-1.0 m depth) of the Solniki paleolake sediments. (Late Saalian) to the end of the Early Vistulian (Kupry- The aim of this study was to reconstruct the evolution of janowicz, 2007). A paleolake sediment of ca. 10 m thick- the Solniki paleolake during its long existence, and its ness was discovered at Solniki during cartographic works water conditions (water level, trophic state and water tem- for the Trześcianka sheet of the Detailed Geological Map perature) based on Cladoceran investigations. These re- of Poland. Prof. M. Kupryjanowicz. started the palyno- sults were compared to the previously published pollen logical study of the Solniki profile demonstrating the data, which define the vegetation history of the surround- Eemian and Early Vistulian age of the discovered paleo- ing area. Special attention was paid to the Early Vistulian lake (Kupryjanowicz et al., 2005; Kupryjanowicz, 2008). period, because of the scarcity of investigation of subfos- Subfossil Cladocera analysis was performed for this pro- sil Cladocera for this period. file in order to complement and expand environmental in- formation provided by the palynological data. Subfossil Cladocera are an useful tools in paleolim- METHODS nology. They are a widespread and well studied compo- Study site and chronology of the profile nent of the microfauna in lakes and ponds, and are commonly used as environmental indicator in aquatic The Solniki site (53°30′N,only 23°12′ E; 143 m asl) is lo- ecosystem management (Jeppesen et al., 2011). In fact cated in the central part of the Białystok Upland (NE distribution and abundance of Cladocera is affected by Poland, Fig. 1), approximately 18 km south of Białystok habitat properties (Korhola, 1990), as well as by factors and ~4 km south-west of Zabłudów (Kupryjanowicz, such as trophy (Szeroczyńska, 1998a, Nevalainen and 2008). Theuse region’s relief was formed by the Wartanian Luoto, 2016), acidification (Krause-Dellin and Steinberg, Glaciation (Saalian, Riss Glaciation) (Musiał, 1992). The 1986), water temperature (Poulsen, 1944; Hofmann, maximal range of the last glaciation (Vistulian, Weische- 2000, Nevalainen et al., 2013) and fish predation (Jeppe- lian) lies ~50 km north of this site (Marks, 2002). The pa- sen et al., 2001; Korhola and Rautio, 2001). leolake lies ~100 m east of the Solniki to Koźliki road, on Subfossil Cladocera analyses in Poland provided de- the left bank of the river Czarna. The studied sediments tailed results for the last 13,000 years (Gąsiorowski, 2002; fill the subglacial basin, which was formed during the Szeroczyńska, 2006; Szeroczyńska and Zawisza, 2007). Wartanian Glaciation (Kurek and Preidl, 2001) and ex- The capability of subfossil Cladocera to support the en- tends over an area of ~700×300 m. The paleolake is sur- vironmental reconstruction for contemporary lakes, led to rounded by moraine and kame hills. considerable interest in the applicability of the methods Coring was carried out in the 1990’s using a geologi- to sediments from the period preceding thecommercial last glaciation. cal corer during the preparation of the Trześcianka sheet Literature on Cladocera succession during the Eemian of the 1:50,000 (Detailed Geological Map of Poland, in a Interglacial is scarce, as only a few locations in the world scale of Kurek and Preidl, 2001). The entire cored se- have been examined, often preliminarly, for cladoceran quence was 162.50 m long, while lake deposits, were subfossils (Tsukada, 1972; Kadota,Non 1975; Hann and Kar- present at depths of between 3.00-11.00 m (Kupryjanow- row, 1984, 1993). The first comprehensive analysis of icz, 2008). The paleolake sediments mainly consisted of subfossil Cladocera from Eemian lake sediments in Eu- organic silts, whereas a peat layer was detected at 11.00- rope was performed in Denmark (Frey, 1962). In Poland, 10.60 m depth below the surface, and appeared covered the first analyses were conducted with material obtained by a 3 m thick deposit of sand. The description of the la- in Konin (Szeroczyńska, 1991). So far, Cladocera analysis custrine-mire series is shown in Tab. 1. Sediments from of sediment from profiles of the Eemian age was per- the Solniki paleolake profile