Titill: | Microbes and the groundwater amphipod Crangonyx islandicus in spring sources in Iceland |
Höfundur: | |
Leiðbeinandi: | Snæbjörn Pálsson |
Útgáfa: | 2020-10 |
Tungumál: | Enska |
Umfang: | 178 |
Háskóli/Stofnun: | Háskóli Íslands University of Iceland |
Svið: | Verkfræði- og náttúruvísindasvið (HÍ) School of Engineering and Natural Sciences (UI) |
Deild: | Líf- og umhverfisvísindadeild (HÍ) Faculty of Life and Environmental Sciences (UI) |
ISBN: | 978-9935-9514-3-4 |
Efnisorð: | Biology; Amphipods; Bacteria; Ciliates; Groundwater; Spring sources; Marflær; Örverur; Grunnvatn; Lindir; Líffræði; Doktorsritgerðir |
URI: | https://hdl.handle.net/20.500.11815/2088 |
Tilvitnun:Ragnhildur Guðmundsdóttir, 2020, Microbes and the groundwater amphipod Crangonyx islandicus in spring sources, PhD dissertation, Faculty of Life and Environmental Sciences, University of Iceland, 178 pp.
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Útdráttur:Crangonyx islandicus is a groundwater amphipod endemic to Iceland. Genetic analysis
suggests that the species has been diverging in Iceland for at least 4.8 Myrs indicating it
has survived in a subglacial refugia as Iceland was repeatedly covered by glaciers during
that time period. The species has probably been inhabiting Iceland since before the island
was formed, when the land bridge to Greenland collapsed into the ocean approximately 15
Mys ago. Currently, their habitat is in the subsurface of spring sources within the lava
fields along the tectonic plate boundary. These spring sources act as a window into the
groundwater, but they are also a complex ecotone where groundwater mixes with surface
water and the terrestrial ecosystem. In this thesis, the microbial community composition
associated with the amphipods and their habitat was examined both to inspect if more taxa
could be found in this unique habitat and to elucidate which processes are likely to shape
the community composition of microbial species in the habitat. The results showed that the
amphipods are accompanied by a few ciliate and bacteria taxa that are unique to these
amphipods but can only be marginally detected in the spring source. Both stochastic and
deterministic processes were found to shape the bacteria and ciliate communities in the
spring source. Variables such as pH, temperature, presence of fish and geographical
location were found to shape the bacterial community while temperature and dispersal was
shaping the ciliate communities. The bacterial community in the water from spring sources
and in the biofilms harbored chemolithoautotrophic taxa, indicating primary production in
the groundwater system, thus, providing a possible explanation for the subglacial survival
of the amphipods during Ice age.
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