Sedimente im arktischen Meereis - Eintrag, Charakterisierung und Quantifizierung
Sediments in Arctic sea ice are important for erosion and redistribution and consequently a factor for the sediment budget of the Arctic Ocean. The processes leading to the incorporation of sediments into the ice are not understood in detail yet. In the present ·study, experiments on the incorporati...
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| Format: | Thesis |
| Language: | German |
| Published: |
1998
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| Subjects: | |
| Online Access: | https://oceanrep.geomar.de/id/eprint/49882/ https://oceanrep.geomar.de/id/eprint/49882/1/Lindemann.pdf |
| Summary: | Sediments in Arctic sea ice are important for erosion and redistribution and consequently a factor for the sediment budget of the Arctic Ocean. The processes leading to the incorporation of sediments into the ice are not understood in detail yet. In the present ·study, experiments on the incorporation of sediments were therefore conducted in ice tanks of The Hamburg Ship Model Basin (HSVA) in winter 1996/1997. These experiments showed that on average 75 % of the artificial sea-ice sediments were located in the brine-channel system. The sediments were scavenged from the water column by frazil ice. Sediments functioning as a nucleus for the formation of frazil ice were less important for the incorporation. Filtration in grease ice during relatively calm hydrodynamic conditions was probably an effective process to enrich sediments in the ice. W ave fields did not play an important role for the incorporation of sediments into the artificial sea ice. During the expedition TRANSDRIFT III (TD III, October 1995), different types of natural, newly-formed sea ice (grease ice, nilas and young ice) were sampled in the inner Laptev Sea at the time of freeze-up. The incorporation of sediments took place during calm meteorological conditions then. The characteristics of the clay rnineral assemblages of these sediments served as references for sea-ice sediments which were sampled from first-year drift ice in the outer Laptev Sea and the adjacent Arctic Ocean during the POLARSTERN expedition ARK XIII (July - September 1995). Based on the clay rnineral assemblages, probable incorporation areas for the sediments in first-year drift ice could be statistically reconstructed in the inner Laptev Sea (eastern, central, and western Laptev Sea) as well as in adjacent regions. Comparing the amounts of particulate organic carbon (POC) in sea-ice sediments and in surface sediments from the shelves of potential incorporation areas often reveals higher values in sea-ice sediments (TD III: 3.6 %DM; ARK Xl/1: 2.3 %DM). This enrichment of POC is ... |
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