Sökning: "introduced species"

Visar resultat 11 - 15 av 185 avhandlingar innehållade orden introduced species.

1. 11. Grazing and the geographical range of seaweeds : The introduced Fucus evanescens and the newly described Fucus radicans

   Författare :Helena Forslund; Lena Kautsky; Ove Eriksson; Veijo Jormalainen; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; non-indigenous species; phlorotannin; herbivore defense; ; Biology; Biologi; Marine ecology; Marin ekologi; Plant Ecology; växtekologi;

   Sammanfattning : Along the coast of temperate oceans brown algae of the genus Fucus form dense stands on rocky shores and are keystone species of the coastal ecosystem. These large seaweeds are perennial and function as substrate for many sessile marine organisms, provide shelter for fauna and juvenile fish, and are food source. A number of abiotic (e.g. LÄS MER

3. 12. Phylogeny and species delimitation in Roccellaceae and Physciaceae (Euascomycetes)

   Författare :Katileena Lohtander; Mats Wedin; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Systematics and phylogenetics; Systematik och fylogeni; systematisk botanik; Systematic Botany;

   Sammanfattning : DNA sequence data (the ITS region and Group I Introns) from the nuclear ribosomal repeat (rDNA), partial β-tubulin gene sequences, RAPD markers, and some morphological characters were analysed phylogenetically in order to examine relationships in lichenized Euascomycetes, from the species level to higher taxonomic levels. The species level studies comprise some so-called species pairs in two families, Roccellaceae (Arthoniales) and Physciaceae (Lecanorales). LÄS MER

4. 13. Sulphonamide Resistance in Neisseria meningitidis and Commensal Neisseria Species

   Författare :Yvonne Qvarnström; Göte Swedberg; Dan Andersson; Uppsala universitet; []
   Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Microbiology; sulphonamide resistance; Neisseria; natural transformation; adaptive evolution; substrate channelling; Mikrobiologi; Microbiology; immunology; infectious diseases; Mikrobiologi; immunologi; infektionssjukdomar;

   Sammanfattning : Extensive use of the sulphonamide drugs against the bacterium Neisseria meningitidis has resulted in drug resistance development. Sulphonamide resistance in N. meningitidis is caused by alterations in the chromosomal folP gene, coding for DHPS (dihydropteroate synthase). LÄS MER

5. 14. The effects of crayfish on interactions in freshwater benthic communities

   Författare :Per Nyström; Biologiska institutionen; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; exotic species; trophic cascades; omnivory; crayfish; Trophic interactions; freshwater; Hydrobiology; marine biology; aquatic ecology; limnology; Marinbiologi; limnologi; akvatisk ekologi;

   Sammanfattning : This thesis examines how freshwater crayfish affect community interactions in benthic food webs. I have mainly studied the influence of the introduced signal crayfish (Pacifastacus leniusculus) on littoral communities, but also the influence of the native noble crayfish (Astacus astacus). LÄS MER

7. 15. The importance of biodiversity for ecosystem processes in sediments : experimental examples from the Baltic Sea

   Författare :Johan Näslund; Jonas Gunnarsson; Sara Sjöling; Nils Kautsky; Antoine Grémare; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Biodiversity; Soft-bottom sediment; Ecosystem processes; Ecosystem function; Benthic-pelagic coupling; Baltic Sea; Trophic interactions; Pollutant biodegradation; Organic matter mineralization; Deposit feeder; Detritivore; Invasive species; Marine ecology; Marin ekologi; marin ekotoxikologi; Marine Ecotoxicology;

   Sammanfattning : Aquatic sediments are, by surface, the largest habitat on Earth. A wide diversity of organisms inhabit these sediments and by their actions they have a large influence on and also mediate many ecosystem processes. LÄS MER