Department of Biosciences, University of Bergen, N-5020 Bergen, Norway.
NORCE Norwegian Research Centre AS, Uni Research Environment, N-5020 Bergen, Norway.
Viruses. 2018 Dec 14;10(12):715. doi: 10.3390/v10120715.
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 and 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.
北极海洋环境经历了光照和营养可用性的剧烈季节性变化。为了研究季节性对北极海洋病毒群落的影响，我们在一个日历年中进行了五次到斯瓦尔巴群岛西部和北部的研究巡航，从地表到 1000 米深处采集水样。我们采用主要衣壳蛋白基因和基因的宏条形码分析，分别调查了感染原核和真核微微型浮游植物的 T4 样肌病毒和大型 dsDNA 病毒。使用流式细胞术评估微生物丰度。宏条形码分析结果表明，季节性是塑造病毒群落的关键因素，而深度在季节性病毒组合内具有多样化效应。病毒多样性和病毒与原核生物的比率（VPR）在春季水华开始时急剧下降，但整个季节都在增加，最终在冬季达到最高水平。这些发现表明，在生产力较低的极地冬季，病毒裂解可能是一个重要过程。此外，冬季病毒群落由与春季-夏季存在的 OTUs 不同的 OTUs 组成。我们的数据首次深入了解了一个迄今尚未描述的海洋生境中的病毒多样性，该生境具有光照和生产力的极端变化。
