Sökning: "western Arctic Ocean"

Visar resultat 1 - 5 av 9 avhandlingar innehållade orden western Arctic Ocean.

1. 1. In the wake of deglaciation - sedimentary signatures of ice-sheet decay and sea-level change : Studies from south-central Sweden and the western Arctic Ocean

   Författare :Henrik Swärd; Matt O'Regan; Martin Jakobsson; Juha Pekka Lunkka; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; paleoenvironmental changes; last deglaciation; sedimentology; Lake Vättern; western Arctic Ocean; Mackenzie Trough; Herald Canyon; Marine Geology; maringeologi;

   Sammanfattning : Lacustrine and marine sedimentary archives help unravel details concerning the withdrawal of large ice sheets and resulting sea-level changes during the last deglaciation (22 -11 kyr). In a series of four manuscripts, this PhD thesis investigates the sedimentological signatures from deglacial processes at three key locations in the northern hemisphere: (i) Lake Vättern (LV) in south-central Sweden, (ii) Herald Canyon (HC) in the western Chukchi Sea, and (iii) Mackenzie Trough (MT) on the westernmost edge of the Canadian Beaufort Shelf. LÄS MER

3. 2. Arctic Ocean benthic foraminifera preservation and Mg/Ca ratios : Implications for bottom water palaeothermometry

   Författare :Natalia Barrientos; Helen Coxall; Martin Jakobsson; Steve Barker; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Arctic Ocean; benthic foraminifera; Mg Ca-temperature; calcite preservation; Marine Geology; maringeologi;

   Sammanfattning : Reconstructions of Arctic Ocean palaeotemperatures are needed to disentangle natural variability from anthropogenic changes and understand the role of ocean heat transport in forcing or providing feedbacks on Arctic climate change. Despite known complications with calcareous microfossil preservation in Arctic Ocean sediments, calcareous benthic foraminifera can be common in interglacial sequences. LÄS MER

4. 3. 231Pa, 230Th and 232Th as tracers of deep water circulation and particle transport : Insights from the Mediterranean Sea and the Arctic Ocean

   Författare :Sandra Gdaniec; Carl Magnus Mörth; Matthieu Roy-Barman; Per Andersson; Laura Robinson; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; protactinium; thorium; Mediterranean Sea; Arctic Ocean; scavenging; marine particles; boundary scavenging; particle transport; geotraces; Marine Geology; maringeologi;

   Sammanfattning : The naturally occurring U and Th-series radionuclides have shown to have a considerable importance for the understanding of biogeochemical processes on Earth and in the ocean. In this thesis, the isotopes 230-thorium (230Th), 232-thorium (232Th) and 231-protactinium (231Pa) are used as tracers of the transport and scavenging of marine particles and water circulation. LÄS MER

5. 4. High Arctic submarine glaciogenic landscapes : their formation and significance

   Författare :Francis Fletcher Freire; Richard Gyllencreutz; Martin Jakobsson; Haflidi Haflidason; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; High Arctic; GrIS; marine geophysics; glaciogenic landscapes; ice streams; submarine slides; Marine Geology; maringeologi;

   Sammanfattning : This thesis is focused on studies of glacial and slope morphology in the high Arctic of western Greenland shelf and the Molloy Hole seafloor spreading area, based on high-resolution acoustic methods and other geophysical data. The main purpose is to improve our understanding of glacial dynamics and associated processes in the marginal region of a large marine-terminating ice sheet. LÄS MER

7. 5. Fluxes and transformation of carbon in the Siberian shelf seas under changing environment

   Författare :Irene Wåhlström; Göteborgs universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Carbon system; Carbon dioxide; Arctic Ocean; Siberian shelf seas; Climate change;

   Sammanfattning : The Arctic is especially vulnerable to the increased air temperature caused by emissions of greenhouse gases to the atmosphere, carbon dioxide being one of them. In this thesis, both fieldwork and modelling of the East Siberian Arctic Shelf (the Laptev Sea and the East Siberian Sea) have been carried out to investigate the carbon system in this region. LÄS MER