Past Climate Change
For putting present and past climate into context, glacial, periglacial, and lacustrine archives of bipolar paleoclimate and paleoecological change are studied along temporal and spatial gradients, with a focus on hotspot regions of current global warming in North America, Siberia, and West Antarctica. Key areas of focus include limnological studies in southern Chile and Canada (Nettilling Lake, Wiyâshâkimî Lake), glaciological studies on the Antarctic Peninsula, and permafrost studies in Alaska (Baldwin Peninsula), all employing isotope geochemical approaches.
Both laboratory and field methods are used for the application and development of paleoecological proxies, with a focus on stable isotope methods in various materials (e.g., ground ice and glacial ice, sediment, organic matter, diatoms). This research focus aims to contribute to a comprehensive understanding of past polar climate and environmental variability on seasonal to decadal to orbital timescales.
The scientific work is closely linked to the activities of the ISOLAB Facility.
Head
Prof. Dr. Bernhard Diekmann (scientist)
Paula Allertseder (scientist)
Patrick Bernhardt (MSc and student assistant)
Janosch Staigl (MSc and student assistant)
Victoria Horn (student assistant)
Dr. Andreas Marent (engineer)
Mikaela Weiner (chemical technical assistant)
Dr. Hannah Bailey
Dr. Camilla Brunello
Dr. Svetlana Kostrova
Dr. Bernhard Chapligin
Dr. Francisco Fernandoy
Dr. Kirstin Hoffmann-Abdi
Dr. Moein Mellat
Dr. Amelie Stieg
Philip Meister
Projects, Cooperations, Networking
(2021-2025)
This joint project with Northumbria University (PI: Sebastian Breitenbach) is funded by the Leverhulme Trust.
It aims at elucidating the complex interplay of seasonal temperature and precipitation dynamics as key driver of permafrost changes in East Siberia. To this end, caves and permafrost exposure will be studied in East Siberia along a transect from the Arctic Ocean to the Lake Baikal.
The objectives of the project are to: (i) Reconstruct (a) mean interglacial temperatures at the southern permafrost boundary using subaqueous cave carbonates and (b) summer temperatures of key glacial and interglacial periods using ostracods, (ii) Reconstruct winter and summer temperatures, and precipitation dynamics of glacial and interglacial periods using different types of relict permafrost ice, (iii) Deduce changes in seasonality, moisture dynamics, and continentality based on results from objectives 1 and 2, and corresponding permafrost response to climate change.
The team at Northumbria University focuses on the analysis of cave and ostracod carbonates using clumped and stable isotopes while the team at AWI focuses on the analysis of ground ice in permafrost, specifically ice wedges and pore ice.
Contact: Thomas Opel, Hanno Meyer
Funding: Leverhulme Grant
(2021-2024)
The main goal of the Changes of water isotopes in Arctic Sea ice, Ocean, and atMosphere (CiASOM) project is to provide a comprehensive description of the present-day Arctic water cycle and related key exchange processes between the atmosphere, ocean, and sea ice, using both instrumental data and climate simulations. As a novel approach, the project exploits the isotopic fingerprint of different components of the hydrological cycle through discrete sampling and continuous monitoring. It combines isotopic measurements on board RV Polarstern taken during the MOSAiC expedition with simultaneously performed measurements from several land-based stations in the Arctic realm. The MOSAiC drift experiment offers the unique possibility to tackle the main hydrological processes occurring in the Central Arctic covering a complete seasonal cycle including the understudied Arctic winter. In the CiASOM project, stable water isotopes (H2 16O, H2 18O, HD16O) are exploited as key parameters for an improved understanding of the present-day water cycle. Due to the recently reduced sea ice coverage, Arctic-derived moisture serves as a new, increasingly important northern hemispheric water source. Contributions of the different Arctic hydrological compartments (i.e. sea water, sea ice, snow, water vapor) surrounding RV Polarstern will be targeted to decipher major exchange processes between atmosphere, ocean, and sea ice.
Contact: Moein Mellat, Hanno Meyer, Martin Werner, Camilla Brunello
Funding: BMBF
(July 2021 - December 2024)
The overall goal of this INSPIRES PhD project is to understand the relationship between recent climate warming, hydrological extreme phases and water quality in pristine and human-influenced Siberian lake systems on decadal time-scales. The research focuses on whether global warming lead to more prominent and frequent hydroclimate extremes and whether there is a difference between natural and anthropogenic impact on Siberian hydrology by comparison of early Holocene and recent warming phases.
To answer these questions sediment cores from pristine and urban Yakutian lakes will be investigated gapless and with a decadal-resolution of the last 300 to 500 years. Furthermore, these records will be compared to sediment records from the Early Holocene with a similar temporal resolution, if achievable, to disentangle the anthropogenic and natural contribution.
For investigations, primarily diatom-δ18O will be used to establish hydrological time-series and detect hydrological extreme phases. Diatom-assemblages will be determined to reconstruct salinity and water quality changes in the lakes. Among further biochemical analyses, mercury levels in particular will be a lake sediment proxy for human-induced contamination.
This project will provide a first hydrological time series of the recent and past hydroclimate extremes, like drought phases, for Siberia. Such information is closely related to tundra fire intensities and feedbacks on permafrost stability. In addition, the project enables the local population in Yakutia to gain significant knowledge in order to better address potential risks of future climate change for local ecosystem services, such as drinking water production.
Contact: Amelie Stieg, Hanno Meyer
Funding: Inspires
(2020-2023)
The goal of PalMod II German Climate Modeling Initiative) is modeling a complete glacial cycle – from the last interglacial to the Anthropocene. These climate modeling efforts are complemented by proxy data synthesis and proxy-model comparison. Our job in Work-Package 3.2.2 is compiling and analyzing oxygen isotope data (δ18O) from lake sediments. These records are of utmost importance since the provide quantitative information on past hydroclimate in terrestrial environments and are in theory directly comparable to climate-model outputs (isotopes in precipitation). However, interpretation of these records is challenging due to hydrological processes within the lake and its catchment. We therefore also assess the signal formation in lake sediment δ18O-records in order to provide more reliable information on the driving factors leaving on imprint on the measured signal. These include, but are not limited to, air temperature, lake water temperature, atmospheric circulation patterns and P/E-ratio.
Contact: Philip Meister, Hanno Meyer
Funding: BMBF
This project is investigating the recent and past climate variability of two high-accumulation regions in West Antarctica - the northern Antarctic Peninsula and the Union Glacier region in the Ellsworth Mountains on the West Antarctic Ice Sheet - and will determine the potential forcing factors for observed changes. To do so, newly collected firn cores from both regions are used as natural climate archives and analysed at high (sub-annual) resolution for density, stable water isotopes and various chemical parameters. New data on accumulation rates and meteorological parameters (e.g. air temperature) as well as information on moisture-source regions and transport paths of precipitating air masses will be collected.
Contact: Kirstin Hoffmann, Hanno Meyer
The Iso-Arc project, which was funded by the AWI Strategy Fund, aims for the first-time detailed determination and description of the water cycle in the Eastern Arctic and its isotope fingerprint (H218O, HD16O). Isotope measurements of water vapor are analyzed and interpreted in combination with ocean and precipitation data and climate simulations with explicit isotope diagnostics.
The subproject of the BMBF project "PLOT - Paleolimnological Transect" that ist carried out at the University of Cologne focuses on the reconstruction of climate and vegetation changes along a 6000 km long latitudinal transect from Lake Ladoga in the west to Lake El´gygytgyn in the East (see map). The reconstruction is based on multi-disciplinary geoscientific analyses of more than 50 m long sediment cores from five lakes, which are to be compared to respective data from the master record that was drilled in 2009 within the scope of the El´gygytgyn Drilling Project. The subproject at the University of Cologne furthermore is responsible for the coordination of the German activities in the Russian-German PLOT project, which is carried out under the umbrella of a bilateral agreement of the Russian and German research ministries on scientific collaboration in the fields of polar and marine research.