This dataset provides chironomid percent-abundance data for an Early Weichselian sediment sequence retrieved from the Nochten mine (Niederlausitz area, Germany) in 2004. Percent-abundances of individual chironomid taxa are presented against relative core depth (m). The lake deposit was encountered in an exposure of Weichselian sediments and was sampled using a box core. The material was dated to the Early Weichselian (ca 80ka BP) using a combination of OSL and 14C dating. A total of 13 samples were analysed for their chironomid content. Samples were taken from the box core, weighted, and subsequently processed in the laboratory (Vrije Universiteit Amsterdam, the Netherlands) using standard protocols – this involved 20min treatment with warm KOH (10%) and sieving over a 100µm mesh. Chironomid head capsules were subsequently handpicked from the residue, mounted on permanent microscope slides, and identified using the literature. This dataset provides chironomid percent-abundances relative to the total count of chironomid head capsules per sample. The chironomid dataset provides insight in the natural evolution of the lake ecosystem and was used to produce a chironomid-inferred July air temperature record.
This seismic crosshole dataset was acquired in the context of the DOVE project (Drilling Overdeep-ened Alpine Valleys) at ICDP site 5068_1 (Tannwald Basin) to image the glacial sediments at sub-meter scale. It consists of the field data with geographical coordinates.
The project aims to investigate the landscape evolution in the Alpine region by drilling overdeep-ened valleys and analyzing the cores (DOVE-Phase 1 Scientific Team, Schaller et al., 2023, Schuster et al., 2024). At site 5068_1 (Tannwald Basin), three boreholes were drilled to a depth of about 160 m depth, reaching the bedrock. Boreholes 5068_1_A and 5068_1_B were flush drilling and bore-hole 5068_1_C was cored. In 2022, the boreholes were used to perform high-resolution crosshole seismic measurements in order to image the glacial sediments at sub-meter scale. This dataset con-sists of the seismic field data with geographical coordinates and is subdivided by
(1) the used source and receiver borehole equipment (P: sparker and 24-station hydrophone string, SV: vertically polarizing shear wave source and three-component geophone string with eight geophones, SH: horizontally polarizing shear wave source and three-component geophone string with eight geophones),
(2) the respective borehole plane (BA, BC, and AC), and
(3) the acquisition geometry (STRING, CIRCLE, LINE_BA, LINE_BC, LINE_AC).
The surface seismic data (CIRCLE, LINE_BA, LINE_BC, LINE_AC) was recorded by three-component geophones. The seismic data is provided in SEGY Rev. 1.0 format together with geometry files in csv-format.
This dataset provides chironomid abundance data for a Mid Weichselian sediment sequence retrieved from the Reichwalde mine situated in the Niederlausitz area (Germany) in 1999. Percent-abundances of individual chironomid taxa are presented against relative core depth (m). The lake deposit was encountered in an exposure of Weichselian sediments and was sampled using a box core. The material was dated to the early Mid Weichselian (ca 50ka BP) using 14C dating. A total of 18 samples were analysed for their chironomid content. Samples were taken from the box core, weighted, and subsequently processed in the laboratory (Vrije Universiteit Amsterdam, the Netherlands) using standard protocols - this involved 20min treatment with warm KOH (10%) and sieving over a 100µm mesh. Chironomid head capsules were subsequently handpicked from the residue, mounted on permanent microscope slides, and identified using the literature. This dataset provides chironomid percent-abundances relative to the total count of chironomid head capsules per sample. The chironomid dataset provides insight in the natural evolution of the lake ecosystem and was used to produce a chironomid-inferred July air temperature record.
The cause of changes in atmospheric carbon dioxide (CO₂) during the recent ice ages is yet to be fully explained. Most mechanisms for glacial–interglacial CO₂ change have centred on carbon exchange with the deep ocean, owing to its large size and relatively rapid exchange with the atmosphere. The Southern Ocean is thought to have a key role in this exchange, as much of the deep ocean is ventilated to the atmosphere in this region. However, it is difficult to reconstruct changes in deep Southern Ocean carbon storage, so few direct tests of this hypothesis have been carried out. Here we present deep-sea coral boron isotope data that track the pH—and thus the CO₂ chemistry—of the deep Southern Ocean over the past forty thousand years. At sites closest to the Antarctic continental margin, and most influenced by the deep southern waters that form the ocean's lower overturning cell, we find a close relationship between ocean pH and atmospheric CO₂: during intervals of low CO₂, ocean pH is low, reflecting enhanced ocean carbon storage; and during intervals of rising CO₂, ocean pH rises, reflecting loss of carbon from the ocean to the atmosphere. Correspondingly, at shallower sites we find rapid (millennial- to centennial-scale) decreases in pH during abrupt increases in CO₂, reflecting the rapid transfer of carbon from the deep ocean to the upper ocean and atmosphere. Our findings confirm the importance of the deep Southern Ocean in ice-age CO₂ change, and show that deep-ocean CO₂ release can occur as a dynamic feedback to rapid climate change on centennial timescales.