Mid_Holocene Climate Variability in Northern German and the Adjacent Sea

Laufende Arbeiten / Work Schedule

Emeis et al. 2003; Blanz unpubl.

Emeis et al. 2003; Blanz unpubl.
Emeis et al. 2003; Blanz unpubl.

To address research question 1 and to identify regional Mid-Holocene climate trends and superimposed decadal-to-millenial-scale climate variability we will establish high-resolution time series of sea surface temperature (SST) and salinity, lake temperature and changes in the hydrological cycle both, in the Skagerrak and at Lake Belau. These time series will allow us, in particular, to determine the magnitude and rate of cooling at the end of the thermal maximum, to identify abrupt changes in Skagerrak and Lake Belau hydrography; and to assess decadal-to-centennial changes in temperature and moisture supply related to NAO (North Atlantic Oscillation) during the thermal maximum and the subsequent climate transition.

To assess the overall Atlantic influence on regional climate variability and to address research question 2 these records will be compared to records of AMOC intensity from the subpolar North Atlantic, as a key area to drive changes in North Atlantic thermohaline circulation. Here we will use records of AMOC (Atlantic Meridional Overturning Circulation) intensity (i.e. SST records along the North Atlantic warm water route, as well as North Atlantic deep water ventilation records).

To address question 3 and to test the potential impact of regional climate variability on regional and local environmental conditions as relevant for social and economic change of Neolithic societies a close collaboration is intended with other SPP-projects.

During Phase 1 we will focus on comparing the newly obtained records of temperature and of changes in the hydrological cycle to high-resolution records of land use intensity already available for Lake Belau and spanning the target time window with high-resolution (e.g. palynological records of land opening/forest clearance as reflected in relative abundances of arboreal pollen (AB), as well as high-resolution records of indicator species for potential climate change; occurrences of colluvia (Dreibrodt and Bork 2006); Potassium contents as a proxy for allochthonous input into the lake (Garbe-Schönberg et al. 1998).

In the second phase new regional compilations of the northern Middle European lake record will become available as intended in the project Dreibrodt/Brauer/Bork and the project Dörfler/Kirleis/Kroll/Nelle to explore the potential marine-to-lacustrine climate links on a more regional scale. Here in particular, data compilations of warve thickness, as well as changes in diatom assemblages, both providing independent indicators for changes in precipitation rates, will allow us to assess changes in the regional hydrological cycle as compared to deuterium excess data.


Working plan

  1. Time series to assess temperature variability (Alkenone measurements, Mg/Ca analysis of benthic foraminifera, TEX86)

  2. Time series of changes in the hydrological cycle (δD)

  3. Time series of general climate variability and cyclicity (XRF scans)

  4. Age control