Abstracts

Being one of the leading polar research organizations in Europe, the Alfred Wegener Institute for Polar and Marine Research (AWI) acts as a motor for the development of polar research technologies. A couple of scheduled Arctic projects has been selected out of a large variety of future activities to be presented here:

1) Subsequent to the AMORE expedition to the Gakkel Ridge jointly performed in 2001 by the two research icebreakers USCGC “Healy” and RV “Polarstern” a further two ship mission is scheduled for 2004. AWI will participate again with RV “Polarstern” and will host the remotely operating vessel (ROV) “Victor6000”. The main focus will be laid on a detailed sampling of the Gakkel Ridge system by means of the ROV which is well appropriate for visual and experimental investigations of ridge structures. The vehicle will take samples at  sites surveyed and pre-investigated by geophysical techniques in 2001. Besides, it is also envisaged to conduct ROV-based experiments and sampling on the Siberian Shelf. Based on the results of the joint Russian-German project on "Siberian River Run-off (SIRRO) the river fans of Ob and Yenesei are targeted. Geological, geochemical and biological processes relevant for the understanding of the input of fresh water, sediments, and organic matter from the rivers to the Kara Sea and the adjacent Arctic Ocean will be subject to ROV investigations.

2) AWI is currently purchasing an autonomous underwater vehicle (AUV) for under-ice research, seafloor and water column surveys. Equipped with acoustic tools like side scan sonar, sub-bottom profiler, swath bathymetry as well as with visual imaging systems the vessel shall perform e.g. autonomous pre-site surveys for future Arctic drill campaigns and further seismic investigations at Arctic ridge systems. Moreover, the AUV is planned to be used for surveying arctic sediment and fauna distribution and tracks of grounded icebergs. In addition, special payload modules capable to trace geochemical parameters in the water column will be developed for the AUV in order to quantify submarine fluid discharge plumes etc.

3) The ARGO system of vertically profiling floats is expected to become the backbone of a global ocean observing system. However, their use under Arctic conditions remains difficult, since the floats have to get to the sea surface to be located and to transmit the measured data via satellite. Instead, AWI promotes a Hybrid Arctic/Antarctic Float Observation System (HAFOS) which shall combine different technologies. It comprises ice resistant profiling subsurface floats, surface drifters on the ice and moored stations. The envisaged system consists of RAFOS (ranging and fixing of sound) type subsurface profiling floats which obtain their position by ranging of sound sources on moored stations. The floats measure vertical profiles of temperature and conductivity/salinity, but do not surface while floating under the ice. As a first stage of development, data will be stored until the floats reach ice-free waters. Later, the floats will be able to communicate with receivers installed on moorings and ice drifters allowing fast satellite data transmission.

4) The central Arctic Ocean has hitherto not been visited by a deep-drilling research vessel (DSDP/ODP) and therefore its long-term environmental history as well as the tectonic structure are poorly known. A European contribution to IODP is needed. A newly designed research ice breaker with a deep ocean drilling capability would provide the opportunity to conduct international, interdisciplinary expeditions during all seasons of the year and to penetrate into permanently ice-covered basins of the central Arctic Ocean. AWI promotes a European consortium of interested institutes/countries to share responsibilities for the planning and construction of a multi-purpose Arctic ice breaker and to coordinate scientific programs.

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