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Visar resultat 1 - 5 av 21 avhandlingar som matchar ovanstående sökkriterier.

1. 1. 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

3. 2. Coastal signals of environmental changes: foraminifera as benthic monitors

   Författare :Inda Brinkmann; Kvartärgeologi; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; benthic foraminifera; proxy calibration; trace element geochemistry; environmental DNA; deoxygenation; drought; coastal environments;

   Sammanfattning : Climate changes, tightly linked to anthropogenic activities, are significantly altering environments and ecosystems globally, such as by increasing marine and coastal deoxygenation or occurrences of extreme weather events. The significance of paleoenvironmental and -climate reconstructions, as well as monitoring of current conditions, for unravelling baseline natural variation, today’s changes and potential future impacts, has been recognised by the Intergovernmental Panel on Climate Change (IPCC) reports. LÄS MER

4. 3. DISCO - Drivers and Impacts of Coastal Ocean Acidification

   Författare :Laurie Charrieau; Kvartärgeologi; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Coastal ocean acidification; Foraminifera; Environmental changes; pH; Salinity;

   Sammanfattning : Ocean acidification, mainly attributed to the increasing anthropogenic CO2 in the atmosphere, is characterised by a lowering pH together with a shift in the sea water carbonate chemistry toward lower concentration of carbonate ions. On the coasts, where the environmental variability is high due to natural and human impacts, ocean acidification mainly affects the frequency, magnitude, and duration of lower pH and lower calcium carbonate saturation events. LÄS MER

5. 4. Late Quaternary Biostratigraphy and Paleoceanography of the central Arctic Ocean

   Författare :Daniela Hanslik; Martin Jakobsson; Marit-Solveig Seidenkrantz; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Arctic Ocean; Quaternary; biostratigraphy; foraminifera; paleoceanography; Other earth sciences; Övrig geovetenskap; Marine Geoscience; marin geovetenskap;

   Sammanfattning : The central Arctic Ocean is one of the least explored deep sea regions and long biostratigraphic sediment records are sparse. The main focus of this thesis is the Arctic Ocean foraminiferal record and its application to reconstruct paleoceanographic variations and summer sea ice cover changes between late Quaternary interglacial periods. LÄS MER

7. 5. Tracing marine hypoxic conditions during warm periods using a microanalytical approach

   Författare :Sha Ni; Centrum för miljö- och klimatvetenskap (CEC); []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; environmental changes; hypoxia; foraminifera; Eemian; Holocene; trace elements; stable isotopes; LA-ICP-MS; synchrotronbased μXRF;

   Sammanfattning : Deoxygenation, i.e. loss of oxygen from the oceans, often considerably influences the aquatic organisms and the wholeecosystem and changes biogeochemical cycles. It results in increasing bottom areas of hypoxia (. LÄS MER