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      The Origin, Genetic Diversity and Taxonomy of the Invasive Diatom Didymosphenia geminata (Bacilliariophyceae) in New Zealand

      Kelly, Sarah Rose
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      Kelly, S. R. (2009). The Origin, Genetic Diversity and Taxonomy of the Invasive Diatom Didymosphenia geminata (Bacilliariophyceae) in New Zealand (Thesis, Master of Science (MSc)). The University of Waikato, Hamilton, New Zealand. Retrieved from https://hdl.handle.net/10289/3584
      Permanent Research Commons link: https://hdl.handle.net/10289/3584
      Abstract
      This thesis describes an investigation of the origin, genetic diversity and

      taxonomy of Didymosphenia geminata, in New Zealand. D. geminata,

      commonly known as Didymo or Rock Snot , is a freshwater diatom, a

      photosynthetic alga with a silica shell. It attaches to rocks and plants by its

      mucilaginous stalks, its large blooms often covering all available

      substrates and causing shifts in community structure. Although it was

      historically associated with high altitude, oligotrophic waters, it is now

      showing increased ecological tolerance. It has been increasing in

      abundance and range in Europe and North America and has been

      introduced into new areas including New Zealand, Iran and India. Since

      the first discovery of D. geminata in New Zealand in October 2004, it has

      spread rapidly across the South Island.

      I have conducted a phylogeographic study of D. geminata samples from

      Europe, Asia, North America and New Zealand, using D. geminata-specific

      primers to amplify the internal transcribed spacer (ITS) region. I

      have also used these primers to amplify the small nuclear ribosomal DNA

      (nrDNA) subunit 18S to investigate the taxonomic placement of D.

      geminata within the pennate diatoms.

      Results from this investigation indicate that D. geminata may belong to the

      Family Cymbellaceae. It appears that D. geminata may have been

      introduced though several different introduction events to North America

      from Europe and then to New Zealand from North America. These results

      can be used to inform strategies regarding the control and management of

      this invasive species, including lending support for continuation of the

      Biosecurity New Zealand program aimed at improving public, and

      especially freshwater users', awareness and responsibility regarding D.

      geminata in New Zealand. This program is especially important as

      dispersal appears to be human-mediated. Limiting the number and source

      of introductions to an area can reduce the potential for increased genetic

      variation and thus adaptation to new environments.
      Date
      2009
      Type
      Thesis
      Degree Name
      Master of Science (MSc)
      Publisher
      The University of Waikato
      Rights
      All items in Research Commons are provided for private study and research purposes and are protected by copyright with all rights reserved unless otherwise indicated.
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      • Masters Degree Theses [2381]
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