Sökning: "stoichiometry"

Visar resultat 1 - 5 av 131 avhandlingar innehållade ordet stoichiometry.

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

    Författare :André Frainer; Roland Jansson; Brendan McKie; Jonathan Benstead; Umeå universitet; []
    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

  3. 2. The role of crustacean zooplankton in pelagic nutrient cycling

    Författare :Tobias Vrede; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Biology; nutrients; freshwaters; food web; Cladocera; Calanoida; stoichiometry; Biologi; Biology; Biologi; limnologi; Limnology;

    Sammanfattning : Herbivorous crustacean zooplankton link phytoplankton and other microorganisms withhigher trophic levels in pelagic food webs. Crustaceans show little intraspecificvariation in somatic C:N:P elemental ratios, which may have implications for theregulation of zooplankton growth and for nutrient cycling. LÄS MER

  4. 3. The effects of cellulosic fiber charges on polyelectrolyte adsorption and fiber-fiber interactions

    Författare :A. Elisabet Horvath; Lars Wågberg; Stefan Zauscher; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; adsorption; electrolyte; polyelectrolyte; polyelectrolyte titration; stoichiometry; fluorescence; CLSM; carboxymethylation; ESCA; charge ration; colloidal interactions; mechanical forces; network strength; floc; CPM; rehometer; Cellulose and paper engineering; Cellulosa- och pappersteknik;

    Sammanfattning : The surface charges of cellulosic fibers contribute to several papermaking operations that influence the manufacture and final properties of paper. This thesis investigates the effect of the surface charges on wet-end chemistry, e.g. LÄS MER

  5. 4. Peatland Bryophytes in a Changing Environment : Ecophysiological Traits and Ecosystem Function

    Författare :Gustaf Granath; Håkan Rydin; Joachim Strengbom; Steven K Rice; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; allometric scaling; chlorophyll fluorescence; competition; decomposition; flooding; mire; N concentration; nitrogen deposition; photosynthesis; succession; stoichiometry; Ecological Botany; Ekologisk botanik;

    Sammanfattning : Peatlands are peat forming ecosystems in which not fully decomposed plant material builds up the soil. The sequestration of carbon into peat is mainly associated with the bryophyte genus Sphagnum (peat mosses), which dominate and literally form most peatlands. LÄS MER

  7. 5. Nutrient Stoichiometry in Benthic Food Webs – Interactions Between Algae, Herbivores and Fish

    Författare :Antonia Liess; Peter Eklöv; Dag Hessen; Uppsala universitet; []
    Nyckelord :Ecology; ecologial stoichiometry; periphyton; grazer; benthos; trophic interactions; nutrient; algae; Ekologi;

    Sammanfattning : The aim of this thesis was to identify general structuring mechanisms in benthic food webs within the framework of ecological stoichiometry theory. Ecological stoichiometry is defined as the balance of multiple chemical substances in ecological interactions and explicitly considers the combined dynamics of key elements such as carbon (C), nitrogen (N) and phosphorus (P). LÄS MER