Líffræðifélag Íslands
Líffræðiráðstefnan 2015

Erindi/veggspjald / Talk/poster E87

Description and comparison of microbial metagenomes in a subglacial lake under the Vatnajökull ice cap, East Skaftárketill

Viggó Þór Marteinsson1,2, Pauline Vannier1, Gregory Farrant1, Eyjólfur Reynisson1, Eric Gaidos 3 and Þorsteinn Þorsteinsson 4

MATIS, Department of Food Safety, Environment, and Genetics, Reykjavík, Iceland. 2 The Agricultural University of Iceland, Hvanneyri, Iceland. 3 Department of Geology and Geophysics, University of Hawaii at Manoa, Honolulu, Hawaii, USA. 4 Icelandic Meteorological Office, Reykjavík, Iceland

Kynnir / Presenter: Viggó Þór Marteinsson

Tengiliður / Corresponding author: Viggó Þór Marteinsson (viggo@matis.is)

"Previous studies show that the subglacial lakes in Vatnajökull host endemic communities of microorganisms adapted to cold, dark, and nutrient-poor waters (Gaidos et al., 2009; Marteinsson et al., 2013). Samples collected from the bottom and the sub-surface in the eastern Skaftárkatlar and a mixture of enrichment cultures (4°to 60°C) (Enr) were analysed by sequencing their metagenomes using the Illumina technology. Around 4 million single reads from each sample with an average length of 107 bp were obtained. These sequences were analysed both functionally and taxonomically. Functional analysis were realised by performing whole metagenome assemblies using SPAdes and CLC AssemblyCell. Contigs were processed through MG-RAST and detected KEGG Orthologs (KOs) were used as reference to recruit the raw reads. The analyses showed virus-associated genes in 7% of the total reads in the lake but not in enrichments and 6,3% of all SSU mTAGs belonged to archaeal sequences. This was not observed previously by using 454TAGs. Bottom sample contained mainly genes associated to anaerobic metabolism such as nitrate reductase which is lacking at the surface. It encompassed mainly three species together recruited (as best hit) ~51,7% of the total reads: Sulfurospirillum deleyianum, Sulfuricurvum kujiense and Sulfurimonas denitrificans, all associated with sulfidic environment. In the sub-surface sample, 17 genera recruit at least 50% of the reads, revealing a more complex microbial assemblage than at the bottom of the lake. Genetic distance analysis of environmental sequences showed that about 50% of the reads do not match to a reference sequence with identity equal to or higher than 93% of identity, revealing an important, yet uncharacterized biodiversity. The enrichment sample was both functionally and taxonomically different from the lake samples."