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BaltRap Projekt (2017-2020)

The national BaltRap network, based at the Leibniz Institute for Baltic Sea Research Warnemünde (IOW), is a project funded in the frame of the Leibniz Competition 2017. BaltRap aims to comprehensively understand the impact of rapid climate change in the southern Baltic Sea region during the Holocene by integrating high-resolution marine (sediments) and terrestrial (lake sediments and tree rings) proxy archives. The network is based on a very close interdisciplinary collaboration between scientists from IOW, the Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), the University of Greifswald (EMAU), and the Helmholtz-Zentrum Potsdam Deutsches GeoForschungsZentrum (GFZ). BaltRap represents an adequate platform to provide a better understanding of the variable sensitivities and response times of the coupled marine-terrestrial system to the combined effects of long term and rapid climate change, and human impact.

TETRABAL Projekt (2017-2020)

Recently developed organic proxies (TEX86, MBT/CBT, OH-GDGT1318/cren) based on glycerol dialkyl glycerol tetraether (GDGT) membrane lipids from ammonia-oxidizing Archaea (Thaumarchaeota) and Bacteria provide a unique tool to reconstruct the temperature history of the Baltic Sea region. However, factors, such as the diversity of GDGTs producers, their distribution in the water column, seasonality and water oxygen concentration may affect the interpretation of GDGTs related proxies. The geographical isolation of the Baltic Sea, its relatively small size, its particular physical and chemical properties (salinity, oxygen) and the existing long-term monitoring time-series represents a unique opportunity to study in details the functioning and application of GDGT-based proxies for brackish and redox-sensitive marginal seas. First, representative soil and river samples from the drainage basin, monthly resolved sediment trap samples, water column samples and surface sediments from the Baltic Sea will be analysed in order to better constrain the origin, season and depth of GDGTs production. Temperature experiments will also be conducted on an enrichment culture of Thaumarchaeota from the Baltic Sea. Second, short sediment cores from oxic and anoxic basins of the Baltic Sea will be analyzed to compare proxy-based temperature estimates with instrumental data over the last 50 years and to assess the potential effects of changing redox conditions and NH4+ concentrations on GDGT-based proxies. Finally, in order to extend the records beyond the instrumental period and to obtain new insights on the climate variability of the Baltic Sea region over the last 2000 years at a multi-decadal to decadal timescale, GDGT-based proxies will be applied on long sediment cores together with other biomarkers. The results of TETRABAL should not only help to better understand the functioning of GDGT-based proxies in brackish and redox-sensitive marginal seas, but also shed new light on the relationships between temperature, primary production and hypoxia in the Baltic Sea case study.

Lake Salda Projekt (2017-2019)

Lake Salda, located in the lake district of Turkey (SW Anatolia), is a unique environment due to its present day stromatolite formation. Stromatolites, also called laminated organosedimentary structures, are present from the Archean to the modern, and are considered as the oldest fossils on Earth. Carbonates, particularly stromatolites, are archives of geochemical and climatic conditions when they formed. The purpose of the project is to investigate geochemical, mineralogical and isotopic characteristics of Lake Salda stromatolites to elucidate (1) which biotic and/or abiotic processes are involved in stromatolite formation, (2) how geochemical conditions shapes these processes, (3) to what extend stromatolites carry these influences (biotic fingerprint?), and (4) which climatic information (e.g. water level, temperature) stromatolites may hold. To achieve these goals laboratory and field approaches will be applied. Fossils, living stromatotiles, recent sediments and water samples from the lake will be collected during a field excursion in order to examine microbiological and sedimentological characteristics of stromatolites, and the chemistry of the lake water. Elucidating formation mechanisms (biotic vs. abiotic), mineralogical and isotopic characteristics of these unusual carbonates may provide valuable information about regional paleoclimatic and paleohydrological changes and, most importantly, about the beginning of life on Earth.

P.I: Nurgul BALCI, Istanbul Technical University, Department of Geological Engineering, Istanbul, Turkey (

Project members: Sena AKCER-ÖN, Muğla Sıtkı Koçman University, Muğla, Turkey; Kürşad Kadir ERIS and Ezgi TOK, Istanbul Technical University, Department of Geological Engineering, Istanbul, Turkey; Jérôme KAISER, IOW, Warnemünde (Germany)

Project funded by Istanbul Technical University - Research Division (Grant ITU–BAP-40585 to NB)