ALBERT

Description: Russian and German scientists have investigated the extreme environmental system in and around the Laptev Sea in the Siberian Arctic. For the first time a major comprehensive research program combining the efforts of several projects addressed both oceanic and terrestrial processes, and their consequences for marine and terrestrial biota, landscape evolution as well as land-ocean interactions. The primary scientific goal of the multidisciplinary program was to decipher past climate variations and their impact on contemporary environmental changes. Extensive studies of the atmosphere, sea ice, water column, and sea-floor on the Laptev Sea Shelf, as well as of the vegetation, soil development, carbon cycle, permafrost behaviour and lake hydrology, and sedimentationon Taymyr Peninsula and Severnaya Zemlya Archipelago were performed during the past years under a framework of joint research activities. They included land and marine expeditions during spring (melting), summer (ice free), and autumn (freezing) seasons. The close bilateral cooperation between many institutions in Russia and Germany succeeded in drawing a picture of important processes shaping the marine and terrestrial environment in northern Central Siberia in Late Quaternary time. The success of the projects, which ended in late 1997, resulted in the definition and establishment of a new major research effort which will concentrate on establishing a better understanding of the paleoclimatic and paleoenvironmental record of the area. This is important because it allows to be able to judge rates and extremes of potential future environmental changes.

Description: PREFACE : The Laptev Sea System The Arctic Ocean, in particular the wide Eurasian shelf seas comprise some of the most sensitive elements of the global environment which are believed to respond at a very early time to Global Change. The renewed interest in the Arctic, the large scale international research efforts devoted to the Arctic, as well as the presently available new technology to carry out research in ice-infested areas, have opened many new avenues to conduct investigations On the variability of the depositional environments of the Eurasian shelf seas. The Laptev Sea is of particular importance in the string of the Eurasian shelf seas because feeding the Transpolar Drift of the Arctic sea-ice Cover it exports relatively the largest amounts of sea ice into the Open Arctic Ocean, because it is farthest away from the influence of the Atlantic and Pacific waters, and because it is under the influence of rapidly changing fresh water fluxes from the Siberian hinterland (Fig. 1, Sea ice drift paths in the Arctic Ocean). The morphology of the seafloor, the rapidly changing coast lines of the fragil Lena Delta Island frame work as well as the presence of submarine permafrost are examples for the dynamics of the entire Laptev Sea System. - Fig. 1 - In order to address the natural properties of the Laptev Sea System a joint research project is carried out between a number of Russian and German research institutions under the framework of the "Laptev Sea System Project" (Fig. 2, Research institutions under the framework of the "Laptev Sea System Project"). Every year expeditions are carried out in the area on Russian or German research vessels where multi-disciplinary and binational working groups are addressing some of the identified scientific themes. Results from these joint investigations are then discussed in a series of RussianIGerman workshops which are held alternatively in Russia or Germany. The second workshop 'Russian-German Cooperation: Laptev Sea System' was held in November 1994 in St. Petersburg in order to assess (1) the state of knowledge of the Laptev Sea and the adjacent continental margin of the deep Arctic, and (2) to develop a research strategy for the marine geosciences in the Laptev Sea and terrestrial werk in East Siberia. The workshop brought together more than 100 scientists, among them meteorologists, sea ice physicists, oceanographers, biologists, chemists, geologists and geophysicists from various Russian and German research institutions. The main goal of the workshop was to promote and coordinate scientific collaboration among scientists from Russia and Germany. Main emphasis have laid on first scientific results of the expeditions within the scope of the interdisciplinary Russian-German research project 'Laptev Sea System', that is present and past oceanography, ecology, and climatology of the Laptev Sea. The workshop was organized into serveral sessions which followed various themes of the environment of the Laptev Sea from their present situation to their geological record: (I) Ciimate and Ice (11) Modern Environment of the Laptev Sea (111) Environmental History of the Laptev Sea (IV) From Siberia to the Arctic Ocean: Land-Sea Connection (V) Strategy and Plans for Future Work (VI) Mid-long Term Perspectives The scientific content of this workshop is documented in this report containing most of the results and discussions. The publication of this volume serves various purposes. It is primarily a forum for scientists working in the Siberian shelf seas, in which the results of many years of research and preliminary shipboard results can be presented. In order to provide all the participants in the workshop with the opportunity for reporting their results, a speedy way of publication was chosen. Thus, each individual author has presented his opinions and views as he or she sees them, reflecting the diversity and complexity of the Laptev Sea system. On the other hand, this volume offers many researchers the possibility of acquainting themselves with methods and results of research into the East Siberian seas as carried out in other parts of the world. Finally, it is hoped that this collection of papers will function as another step toward joint research projects and are base for the expeditions to be carried out in 1995 and the following years. Many of the papers published identify major scientific problems, thus offering new perspectives for future scientific research in polar regions. The nature of the papers, the discussions and the disciplines of the attendees clearly demonstrate that the study of the Laptev Sea System is a multidisciplinary one in an interesting key area involving all branches of the natural sciences, such as ice physics, oceanography, biology and geology, in particular. It thus remains an important example for GLOBAL CHANGE and CLIMATE IMPACT research within international research efforts, e.g. International Arctic Science Committee (IASC), Arctic Ocean Sciences Board (AOSB) or the Nansen Arctic Drilling Programme (NAD). - Fig. 2 - The editors also made an effort, probably not wholly successful, to edit manuscripts by non-English-speaking authors to make them easier to understand. In this process, we hope we have not changed the meanings of the original papers. Above all we thank Bettina Rohr and Daniel Krüger who kindly assisted in editing the papers. The workshop has been sponsored by the German and Russian Ministries for Research and Technology and the meeting was held from the 21st to the 14th of November in 1994 in the Arctic and Antarctic Research Institute in St. Petersburg. We wish to thank these organizations for their financial and logistic support.

Description: The d18Ocalcite composition of planktic foraminiferal shells in 59 samples collected from surface sediments between 34°S (south-eastern Subtropical Gyre) and 56°S (Antarctic Zone of the Antarctic Circumpolar Current) and additionally from 20°S (Walvis Ridge) in the South Atlantic Ocean documents the apparent calcification depth of 24 planktic foraminiferal taxa. Based on the d18Ocalcite signal of their shells, four depth related groups of foraminifera are distinguished, calcifying in a depth between 0 and 50 m (Sphaeroidinella dehiscens, Pulleniatina obliquiloculata, Orbulina bilobata, Globigerinoides sacculifer (with and without sac), Globigerinella aequilateralis, Globigerinoides ruber (white), Globigerina bulloides); 0 and 200 m (Globigerinoides conglobatus, Orbulina universa, Neogloboquadrina dutertrei, Turborotalita quinqueloba, Neogloboquadrina pachyderma (dextral and sinistral)); 100 and 250 m (Globorotalia tumida, Globorotalia menardii, Globigerinella calida, Globorotalia inflata); and deeper than 250 m (Globorotalia hirsuta, Globorotalia scitula, Globorotalia crassaformis, Globorotalia truncatulinoides (dextral and sinistral)). We propose a method to reconstruct temperature gradients between various depths in the water column, but most specifically between 30 m and 250 m, using the d18Ocalcite composition of foraminiferal calcite. Changes in past sea-surface water stratification in the temperate southern South Atlantic Ocean and in the Antarctic Circumpolar Current can be reconstructed in particular with G. bulloides, G. truncatulinoides and G. inflata. Modern temperature gradients between 30 m and 250 m water depth are reconstructed accurately within a range between 1.7 and 9.4 °C with a correlation coefficient of 0.77 and a standard deviation of ±1.3 °C.