Seasonality Drives Microbial Community Structure, Shaping both Eukaryotic and Prokaryotic Host–Viral Relationships in an Arctic Marine Ecosystem

The Arctic marine environment experiences dramatic seasonal changes in light and nutrient availability. To investigate the influence of seasonality on Arctic marine virus communities, five research cruises to the west and north of Svalbard were conducted across one calendar year, collecting water fr...

Full description

Bibliographic Details
Published in:Viruses
Main Authors: Ruth-Anne Sandaa, Julia E. Storesund, Emily Olesin, Maria Lund Paulsen, Aud Larsen, Gunnar Bratbak, Jessica Louise Ray
Format: Article in Journal/Newspaper
Language:English
Published: MDPI AG 2018
Subjects:
MCP
g23
Online Access:https://doi.org/10.3390/v10120715
https://doaj.org/article/f92d53597c7947729e38f0ff5ac43ab7
Description
Summary:The Arctic marine environment experiences dramatic seasonal changes in light and nutrient availability. To investigate the influence of seasonality on Arctic marine virus communities, five research cruises to the west and north of Svalbard were conducted across one calendar year, collecting water from the surface to 1000 m in depth. We employed metabarcoding analysis of major capsid protein g23 and mcp genes in order to investigate T4-like myoviruses and large dsDNA viruses infecting prokaryotic and eukaryotic picophytoplankton, respectively. Microbial abundances were assessed using flow cytometry. Metabarcoding results demonstrated that seasonality was the key mediator shaping virus communities, whereas depth exerted a diversifying effect within seasonal virus assemblages. Viral diversity and virus-to-prokaryote ratios (VPRs) dropped sharply at the commencement of the spring bloom but increased across the season, ultimately achieving the highest levels during the winter season. These findings suggest that viral lysis may be an important process during the polar winter, when productivity is low. Furthermore, winter viral communities consisted of Operational Taxonomic Units (OTUs) distinct from those present during the spring-summer season. Our data provided a first insight into the diversity of viruses in a hitherto undescribed marine habitat characterized by extremes in light and productivity.