Ecological interaction between bacteriophages and bacteria community during the early white night and mid-summer in Sub-arctic Kongsfjorden bay of Svalbard (Norway)

Abstract

Marine viruses including viruses and phages infect various marine organisms. However, little is known about the diversity of marine viruses and their relationships with their hosts in marine environments. This study investigated the co-occurrence between marine DNA bacteriophages (phages) and the bacteria community in the sub-Arctic area using metagenomics tools in the Kongsfjorden Bay of Svalbard (Norway) in April and June 2018. Among all identified marine viruses, 48-81% were phages involving the families Myoviridae, Siphoviridae, and Podoviridae (in Caudoviriales) as the common groups (order levels). In addition, Puniceispirillum phage HMO-2011 was the most dominant at 7.61% in April, and Puniceispirillum phage HMO-2011 and Pelagibacter phage HTVC008M was the most dominant at 3.32% and 3.28%, respectively, in June. In the bacteria community, Gammaproteobacteria was 58% of the prevalent group (class level) and Eionea flava (14.3%) and Pseudomonas sabulinigri (12.2%) (Gammaproteobacteria) were the most predominant taxa in April, but Alphaproteobacteria showed an absolute predominance of 87%, and Sulfitobacter profundi and Loktanella acticola (Alphaproteobacteria) were the most predominant taxa at 51.5% and 32.4%, respectively, in June. In species-specific relationship between bacteria and phages, Puniceispirillum phage HMO-2011 and Synechococcus phage S-SSM7 was stronger correlated with Eionea flava (r=0.764, p<0.01) and Sulfitobacter profundi (r=0.842, p<0.01), respectively. This relationship between phages and bacteria community may be caused by changes in response to environmental changes, such as increases in water temperature and light intensity. Taken together, these findings are particularly relevant considering the anticipated impact of phages-induced bacterial control mechanisms on the Sub-Arctic Kongsfjorden ecosystem.