 |
| Titel |
Diatoms as paleoecological indicators of environmental change in the Lake Czechowskie catchments ecosystem (Northern Tuchola Pinewoods, Poland) |
| VerfasserIn |
Monika Rzodkiewicz, Izabela Zawiska, Agnieszka Maria Noryśkiewicz, Milena Obremska, Florian Ott, Mateusz Kramkowski, Michał Słowiński, Mirosław Błaszkiewicz, Achim Brauer |
| Konferenz |
EGU General Assembly 2016
|
| Medientyp |
Artikel
|
| Sprache |
en
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250129652
|
| Publikation (Nr.) |
 EGU/EGU2016-9795.pdf |
|
|
|
|
|
| Zusammenfassung |
| In this study we investigated four cores of biogenic sediments from the lakes located in close vicinity. Three cores are situated along a transect in the Lake Czechowskie basin from its deepest point towards a former lake bay. The fourth sediment core was retrieved from the nearby Trzechowskie paleolake. Lake Czechowskie is located in the northern part of the Tuchola Pinewoods District (Northern Poland) in a young glacial landscape. At present, the majority of the area is forested or used for agriculture.
The main focus was of the study was Late Glacial and early Holocene period. We performed diatom, Cladocera and pollen analyses, the chronology was established by varve counting, confirmed by AMS 14C dating and Laacher See Tephra (Wulf et. all 2013). In this study we focused on the results of diatom analyses. Diatom assemblages are integrated indicators of environmental change because their distributions are closely linked to water quality parameters including such as nutrient availability.
At the beginning of Allerød there are more eutrophic diatom taxa such as Staurosira construens, Pseudostaurosira brevistriata, Staurosira pinnata. These species are widely distributed in the littoral mainly freshwater, many of which are species of epiphytic, preferring water rich in nutrients. At the end of the Allerød we observe significant changes within diatom assemblages. The increase of planktonic Cyclotella comensis together with the decrease of benthic Stauroseria construens indicate the shortening of time with ice cove on the lake and longer time with summer stratification. In the Younger Dryas cooling we can see the increase of the abundance of diatom Staurosira construens which indicate cold spring and late ice-out (Bradbury et al., 2002). At the early Holocene planktonic diatoms increase in particular Cyclotella comensis, Punciculata radiosa and Cyclotella praetermissa. Some of Aulacoseira species at the end of Younger Dryas. The Holocene sediments showed no variation of the species composition. Planktonic diatoms dominate in all studied location, expecially Cyclotella comensis, Punciculata radiosa, Cyclotella praetermissa and Stephanodiscus parvus.
The results of our research shows that diatom communities were sensitive to climatic changes, which are well reflected in lake environment conditions. The strongest shifts in species assemblagess were noted at the beginning of the Allerød, the Younger Dryas onset and the transition into the early Holocene. The Late Glacial climate fluctuations caused more abrupt lake environment changes than during the Early Holocene.
This study is a contribution to the Virtual Institute ICLEA (Integrated Climate and Landscape Evolution Analysis) funded by the Helmholtz Association. The research was supported by the National Science Centre Poland (grant NCN 2011/01/B/ST10/07367).
Literature:
Bradbury, P., Cumming, B., Laird, K., 2002. A 1500-year record of climatic and environmental change in ElkLake, Minnesota III: measures of past primary productivity. Journal of Paleolimnology 27, 321-340
Wulf S., Ott F., Słowiński M., Noryśkiewicz A. M., Drager N., Martin-Puertas C., Czymzik M., Neugebauer I., Dulski P., Bourne A., Błaszkiewicz M., Brauer A. 2013. Tracing the Laacher See Tephra in the varved sediment record of the Trzechowskie palaeolake in central Northern Poland. Quaternary Science Reviews, s. 129–139. |
|
|
|
|
|
|