We are currently leading or are involved in the following national and international projects funded by th HGF, BMBF, DFG and EU.
REKLIM Regional climate change, Helmholtz Initiative, Topic 8: Abrupt climate change derived from proxy data
Topic 8 aims at identifying and explaining regional and temporal patterns of climate variability between the Pacific and Atlantic region as well as between lower and higher latitudes. The time span of the investigations encompasses the last 140.000 years and focusses on time scales from years to millennia. This time span allows scientists not only to analyze the rapid climate change during the last glacial termination and during the Holocene, but also to compare it to the second last glacial-interglacial transition and the following interglacial, the Eemian.
Paleoclimatic Evolution of the Arctic and Subarctic Oceans Since the Last Glacial Period: Sino-German Pacific-Arctic Experiment” (SiGePAX)
This project aims at identifying the paleoceanographic changes in the Arctic and northwest Pacific region during the last deglacial and the Holocene. This region is highly sensitive to global climate change and provides physical as well as biogeochemical feedbacks. The combination of joint generation of new quantitative paleodata from the Alfred Wegener Institute and the First Institute of Oceanography State Oceanic Administration (FIO, China) – in collaboration with other partners – provides a pioneering, unmatched spatial and temporal coverage of proxy records in this area.
Contact: Lester Lembke-Jene, Ralf Tiedemann
The Manihiki Plateau - Origin, Structure and Effects of Oceanic Plateaus and Pleistocene Dynamic of the West Pacific Warm Water Pool (Manihiki II)
From the paloceanographic perspective, the location at the south-eastern margin of the West Pacific Warm Water Pool makes the Manihiki Plateau a key area in reconstructing its Plio-Pleistocene dynamics and evolution and in investigating the importance and interaction be-tween intermediate waters from the high towards low latitudes. The aim of the research done at AWI is the reconstruction of possible driving mechanisms through the Southern Ocean (“ocean tunnel hypothesis”). The project is part of the cooperative project between the AWI and GEOMAR, funded by the German Ministry of Education and Research (BMBF).
Contact: Nadine Rippert, Ralf Tiedemann
MARUM OC3: High- and low-latitude atmosphere-ocean interactions
Atmosphere-ocean interactions at high latitudes are thought to play a key role in past atmospheric CO2 variability by controlling the sea-ice field, upper ocean physical parameters and stratification, nutrient utilization and biological export, deep-water exposure rates, and high-low latitude exchange of nutrients and heat. For the first time it is possible to study Pleistocene-Pliocene atmosphere-ocean processes in the mid- and high latitude South Pacific using an exceptional set of new sediment cores.
Synthesis of polar proxy records from various archives
In the last decades tremendous advances have been achieved in reconstructing past climatic variability on different time scales by exploiting various types of geological archives including high latitude ice cores, ocean sediments, speleothems and lake sediments. However, most of the obtained proxy time series of past climate variability largely reflect regional signals, with the size or definition of a ‘region’ depending on the type of archive. The next logical step, a compilation of all these valuable information into a global or at least hemispheric synthesis is still lacking and remains a major challenge for the paleoclimate community.
We contribute to this community effort by synthesising marine data generated at AWI from the Southern Ocean, the Arctic Ocean and adjacent Northern polar seas including the Bering Sea, Sea of Okhotsk, subpolar North Pacific, the Labrador Sea and the subpolar North Atlantic. On a core-by-core basis all available and envisaged marine proxies will be compiled and transformed in the data scheme developed within this WG. One major focus will be on the consistency and quality of the age models.
This project is part of PalMod (From the Last Interglacial to the Anthropocene: Modeling a Complete Glacial Cycle).
Contact: Oliver Esper, Frank Lamy
Quantifying CO2 outgassing from the mid-depth South Pacific during the last glacial termination (COPTER, AWI Strategic Fund).
The glacial-interglacial dynamics of atmospheric pCO2 changes are largely controlled by processes in the Southern Ocean. The upwelling systems in this region are considered to represent the pathway of old CO2 from the deep-water toward the atmosphere. Our research project COPTER combines biological, geochemical, and paleoceanographic expertise at the AWI with the overall goal to reconstruct the glacial South Pacific´s carbonate chemistry in order to assess the atmosphere-ocean exchange of CO2 and the processes important for deep ocean carbon storage and release.
Within this project we perform biomarker, geochemical, and radiocarbon studies for establishing the detailed timing of deglacial outgassing, its connection to ice-core records, and its contribution to deglacial atmospheric CO2 rise based on sediment records from the Southern Ocean, the SW Pacific off New Zealand and the SE Pacific off southern Chile. These records will allow for closely spaced radiocarbon dating for the derivation of planktic 14C reservoir ages, high resolution sea surface temperature records, and the reconstruction of deep and intermediate water carbonate chemistry changes (boron isotopes, B/Ca).
Contact: Frank Lamy, Ralf Tiedemann
PECA Project (Pleistocene Environmental and Climatic Conditions in the Gulf of Alaska)
Organic-geochemical analyses of sediment cores obtained during IODP Expedition 341 in the subpolar Northeast Pacific permit the reconstruction of the palaeoenvironmental and climatic conditions in the Gulf of Alaska during the Pleistocene. Sea surface temperatures and primary productivity in the Gulf of Alaska changed significantly during the Mid Pleistocene Transition (1.2 - 0.7 Mio years ago). Preliminary results strengthen a teleconnection between the short- and long-term palaeoceanographic evolution in the North Pacific and the North Atlantic. Further, the comparison of biomarker data with micropalaeontological and sedimentological results reveals feedback mechanisms between the environmental and climatic conditions on land and in the ocean.
Contact: Juliane Müller
Biogenic Opal Isotopes – New Tool for Evaluation of Past Nutrient Cycling and Hydrographic Structure in the Pacific Southern Ocean in Relation to Climate and Antarctic Cryosphere Evolution
The Southern Ocean is a key region regarding past and present climate change. This project focuses on reconstructing the evolution in physical and nutrient properties at surface and subsurface water depth in the Pacific sector of the Southern Ocean. Different climate conditions, from colder than present (e.g. Last Glacial Maximum) to warmer than present (e.g. Marine Isotope Stage 5.5), will be addressed using oxygen and silicon isotopes of siliceous microfossils (diatoms, radiolarians), carefully extracted from selected sediment cores.
Contact: Edith Maier
Benthic foraminiferal stable carbon isotopes as a proxy for organic matter fluxes to the sea floor
We propose to enhance the applicability of benthic foraminiferal stable carbon isotope records as a quantitative proxy for the assessment of organic matter flux to the sea floor. We aim to develop such a proxy based on living (Rose Bengal stained) specimens of selected epi- and infaunal taxa from undisturbed surface sediments of the Mediterranean Sea. Sampling stations were selected from a narrow water depth interval between 500 and 1000 m and are located along strong gradients in surface water productivity and organic matter fluxes. The obtained isotope data will be related by multivariate statistical analyses to site-specific environmental conditions and biogeochemical characteristics of the substrate. Specifically, we will establish a transfer function for the assessment of organic matter flux rates to the sea floor based on the stable carbon isotope signature of the shallow infaunal taxa Uvigerina mediterranea and U. peregrina. In addition, we will explore the potential influence of specific trophic conditions on the ontogenetic relation between test size and the stable carbon isotope signal of the studied taxa. Subsequently, the transfer function will be applied to published isotope records from late Holocene sediment intervals of the Mediterranean Sea in order to reconstruct regional short-term changes in organic matter fluxes and surface water productivity. Our new methodological approach will provide data for the validation of model experiments on the biogeochemical variability of the Mediterranean Sea.
Contact: Andreas Mackensen, Gerhard Schmiedl (Univ. Hamburg), Marc Theodor (Univ. Hamburg)
The dynamics of the West Antarctic Ice Sheet during the Cenozoic
Since several decades the Amundsen Sea sector of the West Antarctic Ice Sheet is subject to dramatic changes. Future projections assume an accelerated retreat into the deep inner basins beneath the current ice sheet, since the grounding line, triggered by the inflow of warmer water masses onto the shelf, continuously retreats into deeper water. This project aims at illuminating the past behavior of the two largest ice streams draining into the Amundsen Sea, the Pine Island and Thwaites glaciers. If these two major ice streams continue retreating into the deep inner basins, they would raise the global sea level by ~1.5 m. In order to assess this threat and to put the current rapid changes into a long-term context, this project combines high-resolution bathymetry, seismic profiles, and sediment cores from the palaeo-ice sheet bed, which is deep seafloor today. These data will help to develop 4D reconstructions of these two major ice streams in order to decipher their extent, flow, and retreat since the Last Glacial Maximum (26.000 - 19.000 years before present). This information will help gauging and improving previously available ice-sheet models that aim at reliably predicting future ice sheet change.
The ventilation and circulation of the southern Indian Ocean on glacial/interglacial timescales (RO5057/1-1)
Connecting the major ocean basins, the circum-Antarctic Southern Ocean plays a key role in the global carbon cycle. Funded by the DFG focus program (SPP) 1158, we focus on the Indian sector of the Southern Ocean in order to assess its part in the carbon cycle and its evolution on glacial/interglacial timescales.
IMCONet WP 5 - Sediment Archives and Glacial Geomorphology
IMCONet is an international Research Network that follows an interdisciplinary approach to understand the consequences of Climate Change in coastal Western Antarctica. A Network for Staff Exchange and Training, IMCONet is funded by the Marie Curie Action IRSES (International Research Staff Exchange Scheme) of the 7th Framework Programme of the European Union. The activity brings European, South American and US scientists together to advance climate and (eco-) system change research at the Western Antarctic Peninsula (WAP), a region of recent rapid aerial warming.
Contact: Gerhard Kuhn, Website: http://www.imconet.eu/about-the-project/work-packages/wp-5.html
Natural variability of Arctic sea ice and its significance for global climate change and organic carbon cycle
Overall scientific goals of a joint study between the Alfred Wegener Institute (AWI), Bremerhaven/Germany, and the Second Institute of Oceanography, State Oceanic Administration (SIOSOA), Hangzhou/China, are related to modern and past changes in Arctic sea ice and its relationship to the Arctic Ocean (paleo-) environment and organic carbon cycle. Organic-geochemical bulk parameters and specific biomarkers are used to reconstruct surface-water characteristics (i.e., sea ice, temperature, salinity, primary production) in the Arctic Ocean and their changes through Quaternary glacial/interglacial time intervals as well as related terrigenous and marine organic carbon fluxes. Of special interest will be the interrelationship between sea-ice cover, freshwater discharge, and primary productivity, as well as the circum-Arctic ice-sheet history.
Contact: Rüdiger Stein
BMBF Project „The Transpolar Drift System“
A joint BMBF-funded research project of institutions in Bremerhaven, Kiel and Mainz has been established to study the formation, drift, extent and melting of Arctic sea ice and interactions with water mass circulation in the Eurasian sector of the Arctic Ocean on different time scales (Last Interglacial, Last Glacial, Holocene, Recent). Within the subproject „Arctic biomarkers“ specific organic compounds (Isoprenoids/IP25, n-alkanes, sterols, etc.) are investigated in order to understand present and past relationships between sea-ice extent, biological productivity, terrigenous input and sea-level change.
DFG-funded International Research Training Group „ArcTrain“ (Processes and impacts of climate change in the North Atlantic Ocean and the Canadian Arctic), a collaborative project between the University of Bremen, the Alfred Wegener Institute, and a consortium of eight Canadian universities. Subproject “Variability of Arctic sea ice, meltwater discharge and primary production through last glacial to Holocene times: A biomarker approach“
Sea ice is a critical component in the global climate system, contributing to changes in Earth’s albedo, biological processes (primary production), and deep-water formation, a driving mechanism of the global thermohaline circulation. In order to understand processes controlling recent dramatic reductions in sea ice cover in the polar regions, it is essential to determine these changes in sea ice occurrence and its natural variability in the past on time scales going back in time beyond the period of direct measurements and observations. In this context, this project will use organic-geochemical bulk parameters and specific biomarkers („IP25“, sterols, n-alkanes, alkenones, etc.) to reconstruct surface-water characteristics in the (sub-) polar North Atlantic (Fram Strait, Greenland Sea, Baffin Bay) and their changes through late Quaternary times. Of special interest will be the interrelationship between sea-ice cover, meltwater discharge, and primary productivity, as well as the Laurentide and Greenland ice-sheet history.