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Visar resultat 6 - 10 av 20 avhandlingar som matchar ovanstående sökkriterier.

1. 6. 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

3. 7. The role of Southern Ocean fronts in the global climate system

   Författare :Robert M. Graham; Agatha de Boer; Alberto Naveira Garabato; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Southern Ocean; fronts; jets; Antarctic Circumpolar Current; wind stress; chlorophyll; iron; Last Glacial Maximum; Marine Geology; maringeologi;

   Sammanfattning : The location of fronts has a direct influence on both the physical and biological processes in the Southern Ocean. However, until recently fronts have been poorly resolved by available data and climate models. LÄS MER

4. 8. Iron in the Lena River basin, NE Russia : Insights from microscopy, spectroscopy and isotope analysis

   Författare :Catherine Hirst; Carl-Magnus Mörth; Per Andersson; Mats Erik Åström; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; iron; reactivity; isotopes; permafrost; river; Arctic; Marine Geology; maringeologi;

   Sammanfattning : Iron is an important mediator of biotic and abiotic processes on the Earth’s surface, being an electron acceptor in organic matter degradation, a surface for organic matter and trace element adsorption, and a required element for enzymatic processes during primary production. Yet, the role of iron as a mediator of carbon and trace element cycling in high latitude, permafrost-dominated regions remains poorly investigated. LÄS MER

5. 9. Systematics and assessment of the chemosynthetic bivalve family Vesicomyidae

   Författare :Frida Hybertsen; Steffen Kiel; Helen Coxall; Elizabeth Harper; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Cenozoic; deep sea; hydrocarbon seeps; chemosynthetic; Bivalvia; Vesicomyidae; maringeologi; Marine Geology;

   Sammanfattning : The deep ocean has fascinated researchers for centuries with discoveries of new ecosystems and species, yet there are still many biogeographic and evolutionary questions unanswered. Along active and passive tectonic margins, specialized ecologies thrive in a symbiosis between chemosynthesizing bacteria and their host animals. LÄS MER

7. 10. Exploring the metagenome of the Baltic Sea sediment

   Författare :Fredrik Hårdeman; Sara Sjöling; Gunnar Sandström; Kornelia Smalla; Södertörns högskola; Karolinska Institutet; Karolinska Institutet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Maringeologi; Bakterier;

   Sammanfattning : Environmental microorganisms are fundamental to ecosystem function, acting as drivers in processes such as primary production, organic matter remineralisation, pollution remediation and global biogeochemical cycling. However, the study of the bacterial communities requires the application of advanced culture-independent methods considering that only a small fraction of the community is otherwise accessed. LÄS MER