Description: The first Holocene marine transgression reached the inner fiords of King George Island approximately at 9.5 ka BP according to Sugden and John (1973). This age marks today the minimum age of the end of the last glacial period obtained on land and the start of the Holocene in this Antarctic sector. Following the first Holocene marine transgression, Watcham et al. (2011) reconstructed a relative sea level curve for the South Shetland Islands with a relative sea level rise of 15.5 m amsl for Fildes Peninsula between 8 and 7 ka BP. The curve shows that a delay occurred in the isostatic uplift after 7.2 ka BP related to a glacier still-stand resulting in a relative sea level rise. This is followed by a drop of the relative sea level after 7 ka BP due to the rate of glacial unloading and isostatic rebound exceeding the rate of eustatic sea level rise. The aim of this presentation is to show new evidence, which will help to understand the postglacial paleoenvironmental changes on King George Island. Our chrono-stratigraphical and geomorphological studies in Potter Peninsula suggest, that the Holocene post-glacial marine transgression was not just initiated before 7.7 ka BP but also reached 14 m amsl, and was locally interrupted by a glacier advance after 7.3 ka BP. This glacier advance can be correlated to Watcham´s et al (2011) curve, showing a drop of relative sea level between 7.2 and 7 ka BP. In conclusion, we consider that a glacier readvance took place between 7.2 and 7 ka BP in the Southern sector of King George Island. Additionally our findings show that the age of 9.5 ka BP as a minimum age of the onset of the Holocene transgression in the South Shetland Islands has to be reconsidered. References Sugden, D. and John, B., 1973. The age of glacier fluctuations in the South Shetland Islands,Antarctica. In: van Zinderen Bakker, E.M. (Ed.), Palaeoecology of Africa, the Surrounding Islands, and Antarctica. A.A. Balkema, 139-159 p., Cape Town. Watcham, E. P., Bentley, M. J., Hodgson, D. A., Roberts, S. J., Fretwell, P. T., Lloyd, J. M., Larter, R. D., Whitehouse, P. L., Leng, M. J., Monien, P. and Moreton, S. G., 2011. A new Holocene relative sea level curve for the South Shetland Islands, Antarctica. Quaternary Science Reviews 30, 3152–3170.

Description: Recent findings of outcrops of the so-called "Explora Wedge" and overlying younger sediments below the Ekström Ice Shelf initiated discussion about discovering this area in more detail. The Ekström Ice Shelf is a characteristic ice shelf and one out of numerous small to medium scale ice shelves around East Antarctica. It is bordered by ice rises and ridges, has only a small catchment area and a slow flowing central ice stream. Nevertheless, this region is of critical importance to water-mass preconditioning in the Weddell Sea, and like other ice shelves in that area particularly susceptible to future environmental changes. We have learned about sub-ice-shelf melting and freezing processes as well as the formation of supercool water and ice platelets mostly through modelling. Observations from land-fast sea ice are still very rare. Ikaite and related inorganic carbonate precipitation, processes probably observed in the ANDRILL sediment cores, may be associated with freezing processes and brine formation in this type of environment. Hardly any measurements exist regarding oceanographic and glaciological seasonal cycles and associated processes below an ice shelf, close to its calving, or at the grounding zones. Observations and detailed spatial mapping of seafloor morphology and composition are difficult and can only be done with the aid of AUVs or ROVs diving below the ice shelf. "Deep SCINI", a ROV that can be lowered through an ice hole, discovered a school of fish hidden under 740 m of ice and 850 km away from the coast and light, living at the grounding zone of the Ross Ice Shelf (WISSARD project). It also discovered a community of sea anemones (Edwardsiella andrillae), a new species, which lives in high densities upside down on the underside of the ice shelf and is part of an unknown system of biogeochemical processes. These are two more examples for living at the edge on Planet Earth. Evidence of these biological, oceanographic and glaciological processes could have been archived in sedimentary deposits. With detailed seafloor mapping and high-resolution reflection seismic we hope to find postglacial and Holocene sediments. A sequence of more than 1000 m thick sediments has been detected lying on top of the "Explora Wedge" in an area between the ice shelf calving line and about 40 km inland below the Ekström Ice Shelf. Up to now, its age is relatively unknown but could range from Cretaceous to Pleistocene. Therefore, this area would be predestined for exploring East Antarctica\'s development from a greenhouse environment after the Gondwana breakup to a Cenozoic icehouse environment, thus enabling us to possibly reconstruct the history and variability of the East Antarctic Ice Sheet. We will present various sites for drill holes and would like to raise awareness and interest within the community of polar researchers. Due to the proximity to the Neumayer III Station, the logistics of possible future investigations will be easier and will have less of an environmental impact than if started elsewhere in Antarctica.

Description: The Kuroshio Current (KC) is the northward branch of the North Pacific subtropical gyre (NPG) and exerts influence on the exchange of physical, chemical, and biological properties of downstream regions in the Pacific Ocean. Resolving long-term changes in the flow of the KC water masses is, therefore, crucial for advancing our understanding of the Pacific's role in global ocean and climate variability. Here, we reconstruct changes in KC dynamics over the past 20 ka based on grain-size spectra, clay mineral, and Sr–Nd isotope constraints of sediments from the northern Okinawa Trough. Combined with published sediment records surrounding the NPG, we suggest that the KC remained in the Okinawa Trough throughout the Last Glacial Maximum. Together with Earth-System-Model simulations, our results additionally indicate that KC intensified considerably during the early Holocene (EH). The synchronous establishment of the KC “water barrier” and the modern circulation pattern during the EH highstand shaped the sediment transport patterns. This is ascribed to the precession-induced increase in the occurrence of La Niña-like state and the strength of the East Asian summer monsoon. The synchronicity of the shifts in the intensity of the KC, Kuroshio extension, and El Niño/La Niña-Southern Oscillation (ENSO) variability may further indicate that the western branch of the NPG has been subject to basin-scale changes in wind stress curl over the North Pacific in response to low-latitude insolation. Superimposed on this long-term trend are high-amplitude, large century, and millennial-scale variations during last 5 ka, which are ascribed to the advent of modern ENSO when the equatorial oceans experienced stronger insolation during the boreal winter.

Description: With this project, we want to enhance our knowledge of the global carbon cycle on glacial/ interglacial time-scales. To achieve this objective, it is of crucial importance to understand the role of the Southern Ocean on the release and uptake of greenhouse gases. As the southern Indian Ocean is currently fundamentally underrepresented in paleoceanographic reconstructions, it is our aim to reconstruct the contribution of this ocean to the atmospheric pattern of CO2. Therefore, we plan to use a novel multiproxy-approach, combining stable (δ13C) and radiogenic (d14C) isotope reconstructions with analyses of B/Ca-derived carbonate ion concentrations on a sediment core depth transect of the Kerguelen Islands. These analyses will provide a detailed insight into the history of water mass ventilation in the Indian Ocean on glacial/interglacial timescales. Ultimately, we want to combine the findings of this project with other water mass ventilation studies (e.g. Skinner et al., 2010; Sarnthein et al., 2013; Ronge et al., under review) and Earth System Modeling. These findings, in combination with previous studies from the Atlantic and Pacific Oceans will for the first time allow a comprehensive reconstruction of CO2-enriched deep-water during the last glacial, the ventilation throughout the deglaciation and the contribution to the atmospheric CO2-level.

Description: Within the scope of Russian–German palaeoenvironmental research, Two-Yurts Lake (TYL, Dvuh-Yurtochnoe in Russian) was chosen as the main scientific target area to decipher Holocene climate variability on Kamchatka. The 5 × 2 km large and 26 m deep lake is of proglacial origin and situated on the eastern flank of Sredinny Ridge at the northwestern end of the Central Kamchatka Valley, outside the direct influence of active volcanism. Here, we present results of a multi-proxy study on sediment cores, spanning about the last 7000 years. The general tenor of the TYL record is an increase in continentality and winter snow cover in conjunction with a decrease in temperature, humidity, and biological productivity after 5000–4500 cal yrs BP, inferred from pollen and diatom data and the isotopic composition of organic carbon. The TYL proxy data also show that the late Holocene was punctuated by two colder spells, roughly between 4500 and 3500 cal yrs BP and between 1000 and 200 cal yrs BP, as local expressions of the Neoglacial and Little Ice Age, respectively. These environmental changes can be regarded as direct and indirect responses to climate change, as also demonstrated by other records in the regional terrestrial andmarine realm. Long-termclimate deteriorationwas driven by decreasing insolation,while the short-term climate excursions are best explained by local climatic processes. The latter affect the configuration of atmospheric pressure systems that control the sources as well as the temperature and moisture of air masses reaching Kamchatka.