White Rose University Consortium logo
University of Leeds logo University of Sheffield logo York University logo

The microbial diversity and function of Arctic supraglacial biomes.

Lutz, Stefanie (2015) The microbial diversity and function of Arctic supraglacial biomes. PhD thesis, University of Leeds.

Lutz_S_Earth&Environment_PhD_2015.pdf - Final eThesis - complete (pdf)
Available under License Creative Commons Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales.

Download (10Mb) | Preview


The main aim of this research project was to improve our understanding of the diversity, function and ecology of glacial microbiomes. Snow and ice algae are critical players in supraglacial habitats and form extensive blooms in spring and summer. Here I present results on the diversity and the function of snow and ice algae on 21 glaciers in 4 Arctic settings: Greenland, Iceland, Svalbard and Sweden. For the first time, I have evaluated the full microbial community composition (i.e., algae, bacteria, archaea) in the main supraglacial habitats, namely green snow, red snow, biofilms, dirty ice, and cryoconite holes. I have cross-correlated these data with metabolic analyses (i.e., metabolomics, pigments, fatty acids) and critical physico-chemical parameters. I found that snow and ice algae were the first communities to appear after the onset of melting and they showed positive net photosynthetic rates indicating accumulation of organic matter. Furthermore, for the first time I have described these communities in Iceland. My data reveal that red pigmented snow algae are cosmopolitan, and independent of location specific geochemical and mineralogical factors. Only six taxa made up >99% of the algal communities: two uncultured Chlamydomonadaceae, Chloromonas polyptera, Chloromonas nivalis, Chloromonas alpina and Raphidonema sempervirens. In contrast, the composition of green snow varied between the studied locations with higher relative abundance of Raphidonema sempervirens and Microglena sp. in Svalbard, and Chloromonas polyptera in Sweden. Furthermore, I show that green and red snow are not successive stages but two independent phenomena with different adaptation strategies. In all sites, bacteria were mostly represented by the phyla Bacteriodetes, Proteobacteria and Cyanobacteria. The bacterial community composition varied between the different habitats on the phylum level, whereas on the class level they also showed strong biogeography. Archaea showed overall low species diversity. The synthesis of pigments and fatty acids in snow and ice algae were mainly driven by nitrogen and less so by phosphorus limitation. This is especially important for pigments which cause a darkening of glacial surfaces. I show that snow and ice algae dramatically decrease surface albedo which will eventully result in higher melting rates of glaciers.

Item Type: Thesis (PhD)
Keywords: Arctic, glaciers, microbial diversity, snow algae, ice algae, albedo, pigments, fatty acids
Academic Units: The University of Leeds > Faculty of Environment (Leeds) > School of Earth and Environment (Leeds)
Identification Number/EthosID: uk.bl.ethos.679814
Depositing User: Ms Stefanie Lutz
Date Deposited: 09 Feb 2016 11:14
Last Modified: 25 Jul 2018 09:51
URI: http://etheses.whiterose.ac.uk/id/eprint/11871

You do not need to contact us to get a copy of this thesis. Please use the 'Download' link(s) above to get a copy.
You can contact us about this thesis. If you need to make a general enquiry, please see the Contact us page.

Actions (repository staff only: login required)