The microbial composition of algal mats in meltwater ponds in nunataks of the Western Dronning Maud Land

Abstract

There is still a major gap in Antarctic microbial research, which limits our understanding of the microbial populations and interactions in the Western Dronning Maud Land. Algal mats in meltwater ponds host a variety of microbial species, which increases the activity that take place in aquatic habitats. Studying the species present gives an indication of the microbial food web and the mechanisms they use to survive these extreme environments. Algal mats were collected from meltwater ponds in several nunataks, namely Roberskollen, Valterkulten, Vasdallen, Sessegen, Grjotøyra, and Svartgryta. The algal samples were examined microscopically to assess the morphology and composition. The majority comprised of Cyanobacteria and green algae. Tardigrades and rotifers were detected in the Sessegen sample and only rotifers were present in the Robertskollen sample. DNA was extracted from the algal samples followed by 18S, 16S, and ITS1-ITS4 gene amplification. Illumina sequencing was performed on the 18S amplified fragments and the 16S and ITS1-ITS4 amplified fragments were Sanger sequenced. The 18S sequences results showed that Chlorophyceae was the dominant phylum for all the sites. The tardigrades and rotifers were identified as Acutuncus antarcticus and Adineta vaga, respectively. The forward and reverse strands of the 16S and ITS1-ITS4 fragments were sequenced and aligned for identification. The green algae, Pleurastrum sp., was the dominant species identified in the ITS1-ITS4 fragments. A few protozoan species were also identified. The 16S forward and reverse strands could not be aligned due to a 100-300 bp gap. Thus, current work is to identify primers which span this gap to enable alignment and identification. Future work will be to compare this season’s (2017-2018. algal mat microbiomes with previous collections (2016-2017. and identify any potential environmental factors affecting the microbial populations in the meltwater ponds. - Abstract as displayed in the - Abstract booklet. The presentation on the day may differ from the - Abstract.