Bathycoccus and micromonas in an winter Arctic metagenome

Aquatic Sciences Meeting, Aquatic Sciences: Global And Regional Perspectives - North Meets South, 22-27 February 2015, Granada, Spain

Phytoplankton and other protists are diverse and ubiquitous in oceanic waters, and have specific growth requirements, which influence their distribution. Climate change is particularly pronounced across the Arctic, and if current trends continue, will be totally free of ice during the summer. While these changes mean that phytoplankton and associated microbial communities will be exposed to more open water and perhaps higher light levels than previously in summer, winter communities will continue to be subjected to long periods of darkness and low light in spring prior to ice out. Curiously even under ice and in the dark of winter, some microbial species survive; for example, small 1-3 µm chlorophytes, maintain their populations and are able to begin exponential growth as early as March when some light penetrates the ice. It is not known how these photosynthetic eukaryotes are sustained over 4-5 months of darkness. Here we analysed a metagenome generated by high throughput Illumina sequencing, from an environmental DNA sample collected from Amundsen Gulf, Beaufort Sea in December 2007. We found a significant proportion of contigs matching Micromonas and Bathycoccus suggesting that these two chlorophytes were well represented in the community following Polar sunset. Our analysis suggests that the Arctic chlorophytes differ substantially from temperate representatives of the same genera and we will report on potential mechanisms for their survival in the absence of light

Peer Reviewed