Sökning: " streams"

Visar resultat 1 - 5 av 324 avhandlingar innehållade ordet  streams.

  1. 1. Breaking the ice effects of ice formation and winter floods on vegetation along streams

    Detta är en avhandling från Umeå : Umeå universitet

    Författare :Lovisa Lind; Umeå universitet.; [2015]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; anchor ice; climate change; in-stream; riparian; river ice; streams; vegetation;

    Sammanfattning : Streams in cold regions are characterized by unique hydrological processes that control flow regime and water levels. One of the most important processes is the formation, growth and melting of different types of ice in and around the stream channel during winter. LÄS MER

  2. 2. Species interactions in streams - effects of predation, competition and ecosystem properties

    Detta är en avhandling från Umeå : Umeå universitet

    Författare :Erika Nilsson; Lunds universitet.; Lund University.; [2008]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; species abundance; behaviour; stable isotopes; habitat complexity; niche width; niche overlap; competition; streams; predation;

    Sammanfattning : Stream ecosystems are dynamic and they have an inherent environmental variability. Organisms that live in streams are adapted to the continuously changing environment and the presence or absence of species are determined by their environmental requirements, while abundance is most often affected by interactions, such as competition and predation, with other species that are found in the same habitat. LÄS MER

  3. 3. Ecosystem functioning in streams Disentangling the roles of biodiversity, stoichiometry, and anthropogenic drivers

    Detta är en avhandling från Umeå : Umeå universitet

    Författare :André Frainer; Umeå universitet.; [2013]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; detrital food web; functional diversity; stoichiometry; nitrogen and phosphorus concentrations; recalcitrant carbon; spatial and temporal species distribution; pools and riffles; isotopes; leaf decomposition rates; land use; restoration; habitat complexity;

    Sammanfattning : What will happen to ecosystems if species continue to go extinct at the high rates seen today? Although ecosystems are often threatened by a myriad of physical or chemical stressors, recent evidence has suggested that the loss of species may have impacts on the functions and services of ecosystems that equal or exceed other major environmental disturbances. The underlying causes that link species diversity to ecosystem functioning include species niche complementarity, facilitative interactions, or selection effects, which cause process rates to be enhanced in more diverse communities. LÄS MER

  4. 4. Toxicity of Inorganic Aluminium in Humic Streams

    Detta är en avhandling från Stockholm : Department of Applied Environmental Science (ITM), Stockholm University

    Författare :Cecilia M. Andrén; Stockholms universitet.; [2012]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Inorganic Al; toxicity; acidification; humic streams; Applied Environmental Science; tillämpad miljövetenskap;

    Sammanfattning : Aluminium (Al) has been recognised as a main toxic factor alongside pH in acidified water ecosystems. The toxic effect of Al has been attributed to inorganic Al (Ali), though there are few in situ studies in ambient humic waters which are the focus of this thesis. LÄS MER

  5. 5. Stream monitoring using near-infrared spectroscopy of epilithic material

    Detta är en avhandling från Umeå : Ekologi, miljö och geovetenskap

    Författare :Jan Persson; Umeå universitet.; [2007]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Streams; environmental monitoring; Water Framework Directive; water quality; biological impact; epilithic material; near-infrared spectroscopy; diatoms; NATURAL SCIENCES Earth sciences; NATURVETENSKAP Geovetenskap;

    Sammanfattning : The European Union Water Framework Directive (WFD), with initiatives to manage surface water resources, has increased the need for fast and inexpensive methods for monitoring conditions in streams. The objective of this thesis is to assess the potential of near-infrared spectroscopy (NIRS) of epilithic material to become such method. LÄS MER