Sökning: "Helen Coxall"

Hittade 4 avhandlingar innehållade orden Helen Coxall.

  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. 231Pa and Th isotopes as tracers of deep water ventilation and scavenging in the Mediterranean Sea

    Författare :Sandra Gdaniec; Per Anerson; Carl-Magnus Mörth; Matthieu Roy-Barman; Helen Coxall; Per Roos; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Protactinium; Thorium; particle transport; deep water circulation; geokemi; Geochemistry;

    Sammanfattning : The naturally occurring isotopes 231Pa and 230Th are used as tracers of marine biogeochemical processes. They are both produced from the radioactive decay of their uniformly distributed uranium parents (235U and 234U) in seawater. LÄS MER

  4. 3. 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

  5. 4. Eastern equatorial Pacific bulk sediment properties and paleoceanography since the late Neogene

    Författare :Daniele Reghellin; Helen K. Coxall; Jan Backman; Gerald R. Dickens; Steve Hovan; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Paleoceanography; late Neogene; eastern equatorial Pacific; deep sea sediments; bulk sediment; stable isotopes; surface mixed layer; sediment physical properties; Marine Geology; maringeologi;

    Sammanfattning : Reconstructing eastern equatorial Pacific (EEP) oceanography since the late Neogene (about 8 million years ago, Ma) is a central topic in current paleoceanographic investigations. The reason for this is two-fold. LÄS MER