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| Titel |
Linking varve-formation processes to climate and lake conditions at Tiefer See (NE Germany) |
| VerfasserIn |
Nadine Dräger, Ulrike Kienel, Birgit Plessen, Florian Ott, Brian Brademann, Sylvia Pinkerneil, Achim Brauer |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250143833
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| Publikation (Nr.) |
 EGU/EGU2017-7593.pdf |
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| Zusammenfassung |
| Annually laminated (varved) lake sediments represent unique archives in continental areas
providing both, precise chronologies and seasonally resolving proxy data. Monitoring of
physical, chemical and biological processes influencing lake sediment formation are a
suitable approach for detailed proxy understanding of varved sediment records.
Lake Tiefer See (NE Germany) indicates deposition of varved sediments today as
well as millennia ago (Dräger et al., 2016; Kienel et al., 2013). Therefore, the lake
provides the possibility to trace current seasonal layer formation in the lake and to pair
these data to climate and lake conditions (Kienel et al., 2016). Lake Tiefer See
was formed during the last glaciation and is part of the Klocksin Lake Chain, a
subglacial channel system that crosses the Pomeranian terminal moraine. The lake is a
mesotrophic hard water lake with a maximum depth of 63 m and a surface area of 0.75
km2.
During four consecutive years (2012-2015) the particulate matter deposition was trapped
at bi-weekly to monthly resolution at three different water depths (5, 12 and 50 m). The
sediment trap material was analysed for sediment flux and organic matter and calcite content.
In addition, we monitored limnological parameters (e.g. temperature, pH, conductivity,
oxygen content) as well as the meteorological conditions (e.g. temperature, wind speed
and direction, precipitation) with a monitoring and climate station installed on the
lake. These data describe strength and duration of lake mixing and lake stagnation
phases.
Our results show distinct seasonal peaks in sediment formation, which correspond
to the spring and summer productivity phases comprising of diatom blooms and
calcite precipitation. This observation is in line with microfacies results from surface
sediment cores. The content of biogenic calcite content decreases in the trapped
material with increasing water depth indicating dissolution processes. However, the
strength of calcite dissolution varies between seasons and years. We will discuss the
depositional processes in relation to conditions in the water column and to meteorological
data.
This study is a contribution to the Virtual Institute of Integrated Climate and
Landscape Evolution Analysis –ICLEA– of the Helmholtz Association; grant number
VH-VI-415.
Dräger N, Brauer A, Theuerkauf M, Szeroczyńska K, Tjallingii R, Plessen B, Kienel U
and Brauer A (2016) A varve micro-facies and varve preservation record of climate change
and human impact for the last 6000 years at Lake Tiefer See (NE Germany). The Holocene
online first.
Kienel U, Dulski P, Ott F, Lorenz S and Brauer A (2013) Recently induced anoxia leading
to the preservation of seasonal laminae in two NE-German lakes. Journal of paleolimnology
50 (4): 535–544.
Kienel U, Kirillin G, Brademann B, Plessen B, Lampe R and Brauer A (2016) Effects of
spring warming and mixing duration on diatom deposition in deep Tiefer See, NE Germany.
Journal of paleolimnology 57 (1): 37-49. |
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