Sökning: "subtropics"

Visar resultat 1 - 5 av 10 avhandlingar innehållade ordet subtropics.

  1. 1. Significance of N2 fixing planktonic symbioses for open ocean ecosystems

    Författare :Marcus Stenegren; Rachel A. Foster; Agneta Andersson; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; nitrogen fixation; diazotrophs; symbiosis; DDA; cyanobacteria; qPCR; piecewise SEM; microarray; tropics; subtropics; marine; open ocean; Richelia; Calothrix; Marine Ecology; marin ekologi;

    Sammanfattning : Di-nitrogen (N2) fixers, also called diazotrophs, are able to reduce atmospheric N2 into bioavailable nitrogen, giving them an advantage in open ocean regions with low dissolved inorganic nitrogen concentrations. The focus of this thesis are three lineages of symbiotic heterocystous filamentous types (het-1, het-2 and het-3), that associate with several genera of microalgae called diatoms (collectively referred to as Diatom Diazotroph Associations, DDAs). LÄS MER

  3. 2. The influence of clouds on Earth's radiation budget in global climate models

    Författare :Johannes Karlsson; Gunilla Svensson; Henning Rodhe; Bjorn Stevens; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Atmosphere and hydrosphere sciences; Atmosfärs- och hydrosfärsvetenskap; Meteorology; Meteorologi; Oceanography; Oceanografi; atmosfärvetenskap och oceanografi; Atmospheric Sciences and Oceanography;

    Sammanfattning : Considering the high sensitivity of climate to changes in cloudiness, the way clouds might change in a perturbed climate is important for the total temperature response. In fact, the cloud feedback has been identified as the main uncertainty in future projections, as simulated by global climate models. LÄS MER

  4. 3. A geophysical investigation of carbonate build-ups in the Baltic Basin using reflection seismic and well data

    Författare :Tegan Levendal; Christopher Juhlin; Lars Nielsen; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Reflection seismic; Ordovician; Silurian; Carbonate mud mounds; Reefs; Gotland; Sweden; CAES; Seismic interpretation; OPAB dataset; 3D seismic; Geofysik med inriktning mot fasta jordens fysik; Geophysics with specialization in Solid Earth Physics;

    Sammanfattning : During the Late Ordovician, the region around Gotland was part of a shallow epicratonic basin in the southern subtropics. Low latitudes, relatively warm sea temperatures and the presence of a shallow marine environment promoted algae to flourish and diverse carbonate build-ups such as carbonate mounds and reefs developed on the southern margin of Baltica. LÄS MER

  5. 4. Observations of water vapour in the middle atmosphere

    Författare :Stefan Lossow; Jörg Gumbel; Jacek Stegman; Daniel R. Marsh; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; water vapour; mesosphere; stratosphere; dynamics; Odin satellite; limb sounding; microwave; tropics; polar winter; Meteorology; Meteorologi; meteorologi; Meteorology;

    Sammanfattning : Water vapour is the most important greenhouse gas and plays a fundamental role in the climate system and for the chemistry of the Earth's atmosphere. This thesis presents observations of water vapour in the middle atmosphere with a particular focus on the mesosphere. LÄS MER

  7. 5. Arctic clouds - interactions with radiation and thermodynamic structure

    Författare :Joseph Sedlar; Michael Tjernström; Annica Ekman; Johannes Verlinde; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Arctic; stratus; radiation; thermodynamic structure; cloud radiative forcing; seasonal transition; Meteorology; Meteorologi; atmosfärvetenskap; Atmospheric Sciences;

    Sammanfattning : Clouds play in important role in the climate system through their interaction with radiation. Globally, clouds tend to cool the Earth by reflecting solar radiation and shading the surface. LÄS MER