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Paleoklimatologia : co nam powie skład izotopowy węgla

Popkiewicz Marcin, Kardaś Aleksandra

LAB Laboratoria, Aparatura, Badania

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2020

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R. 25, nr 1

37--42

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Palaeotemperature estimation in the Holsteinian Interglacial (MIS 11) based on oxygen isotopes of aquatic gastropods from eastern Poland

Szymanek M.

Acta Geologica Polonica

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2017

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Vol. 67, no. 4

585--605

EN

For quantitative estimation of past water temperature of four Holsteinian (MIS 11) palaeolakes from eastern Poland, the oxygen isotope palaeothermometer was applied to shells of the aquatic gastropods Viviparus diluVianus and Valvata piscinalis. The δ18O composition of their shells demonstrated the average growth-season water temperatures during the mesocratic stage of the interglacial (Ortel Królewski Lake), during its climatic optimum – the Carpinus–Abies Zone (Ossówka-Hrud, Roskosz and Szymanowo Lakes), and in the post-optimum (Szymanowo Lake). The calculation was based on δ18O Shell values and the δ18O Water assumed for the Holsteinian from the modern oxygen isotope composition of precipitation and the expected amount of evaporative enrichment. The mean oxygen isotope palaeotemperatures of Ortel Królewski lake waters were in the range of 18.1–21.9°C and were uniform for the Taxus and Pinus–Larix zones. Ossówka-Hrud and Roskosz Lakes had mean temperatures of 17.4–21.0°C during the climatic optimum, whereas the temperature of Szymanowo lake waters was estimated at 20.6–21.7°C at that time. These values are concordant with the pollen-inferred July air temperatures noted during the Holsteinian in eastern Poland. Relatively high values of ~25°C in the post-optimum noted at Szymanowo were connected with the presence of a shallow and warm isolated bay indicated by pollen and mollusc records.

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Inter- and intra-specific variability in δ13C and δ18O values of freshwater gastropod shells from Lake Lednica, western Poland

Apolinarska K., Pełechaty M.

Acta Geologica Polonica

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2017

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Vol. 67, no. 3

441--458

EN

This study focuses on the inter- and intra-specific variability in δ13C and δ18O values of shells and opercula of gastropods sampled live from the littoral zone of Lake Lednica, western Poland. The δ13C and δ18O values were measured in individual opercula of Bithynia tentaculata and in shells of Bithynia tentaculata, Gyraulus albus, Gyraulus crista, Lymnaea sp., Physa fontinalis, Radix auricularia, Theodoxus fluviatilis and Valvata cristata. The gastropods selected for the study are among the species most commonly found in European Quaternary lacustrine sediments. The carbon isotope composition of the gastropod shells was species-specific and the same order of species from the most to the least 13C-depleted was observed at all sites sampled. Differences in shell δ13C values between species were similar at all sampling sites, thus the factors influencing shell isotopic composition were interpreted as species-specific. The δ18O values of shells were similar in all the species investigated. Significant intra-specific variability in shell δ13C and δ18O values was observed not only within the populations of Lake Lednica, which can be explained by heterogeneity of δ13C DIC, δ18O water and water temperature between the sites where macrophytes with snails attached were sampled, but also between individuals sampled from restricted areas of the lake’s bottom. The latter points to the importance of factors related to the ontogeny of individual gastropods.