Changes in macrophytic flora and planktonic organisms in Lake Ostrowite, Poland, as a response to climatic and trophic fluctuations

Abstract

This article presents some selected results of palaeoecological analysis based on subfossil pollen and Cladocera in a core of deep-water sediments. It was drilled in the SW part of Lake Ostrowite in National Park Bory Tucholskie, Poland. The core contains fine-detritus gyttja with no calcium carbonate. Nine local pollen assemblage zones show the stages of vegetation succession around the lake from the Younger Dryas through the Holocene up to the present time. Local pollen assemblage zones and seven phases in the development of Cladocera permit ecological reconstruction and description of local changes in the lake itself. Changes of trophic status are based on the quality and quantity of Cladocera species and the curve of Pediastrum. Human activity around Ostrowite is discussed in relation to the changes in regional plant cover and the trophic state of the lake.

Subfossil faunal and floral remains (Cladocera,Pediastrum) in two northernLobelialakes in Finland

“…Common taxa for all of these lakes are e.g. Rynchotalona falcata, Alonopsis elongata, Daphnia pulex-group (Milecka and Szeroczyñska, 2005). It can be assumed, however, that the subfossil Cladocera and Pediastrum species composition confirmed in NE Finland is typical for Lobelia lakes.…”

Autogenic succession, land-use change, and climatic influences on the Holocene development of a kettle-hole mire in Northern Poland

“…The dates were calibrated using the OxCal 3.8 program (Bronk Ramsey, 1995. Additional dates were inferred from the regional pollen signals by comparison with a record from Lake Ostrowite, which is located approximately 25 km from the study site (Milecka and Szeroczyńska, 2005).…”

“…For DWT we excluded samples with residuals higher Table 1 Radiocarbon dates obtained by radiocarbon (AMS) dating. Poz -dates for Tuchola mire (T4 core), OSTI -OST V -dates inferred from palynostratigraphic correlation with radiocarbon dated Ostrowite lake core (Milecka and Szeroczyńska, 2005) than: 20 cm, 10 cm, 8 cm, 7 cm and 6 cm. For pH samples with residuals higher than 2, 1, 0.7, 0.5 and 0.3 units were removed from the training set.…”

“…Age-depth model of Tuchola mire. Squares: calibrated radiocarbon dates; circles: dates obtained by palynostratigraphic correlation between Tuchola mire (TUCH) and Lake Ostrowite (Tuchola Pinewoods) (Milecka and Szeroczyńska, 2005). The dates given in the figures correspond to radiocarbon dates.…”

Multi-proxy studies in palaeolimnology

“…Cladoceran ecology has always been of more interest than climate reconstruction from the whole group (e.g. Hofmann 1996Hofmann , 2000Duigan and Birks 2000;Milecka and Szeroczyńska 2005). Coleopteran ecology has also always played a large role in palaeoecological investigations although climate reconstructions using MCRM have now become dominant (e.g.…”