Influence of Irradiance and Temperature on the Virus MpoV-45T Infecting the Arctic Picophytoplankter Micromonas polaris

• Published in: Viruses
• Main Authors: Gonçalo J. Piedade, Ella M. Wesdorp, Elena Montenegro-Borbolla, Douwe S. Maat, Corina P. D. Brussaard
• Format: Article in Journal/Newspaper
• Language: English
• Published: MDPI AG 2018
• Subjects: Arctic algal viruses; Light intensity; Light regime; Global Climate Change; Virus growth characteristics; Microbiology; QR1-502; Arctic; Climate change; Global warming; Phytoplankton
• Online Access: https://doi.org/10.3390/v10120676; https://doaj.org/article/4deea11ee4384c03af3e8256874fd4cb

Arctic marine ecosystems are currently undergoing rapid changes in temperature and light availability. Picophytoplankton, such as Micromonas polaris , are predicted to benefit from such changes. However, little is known about how these environmental changes affect the viruses that exert a strong mortality pressure on these small but omnipresent algae. Here we report on one-step infection experiments, combined with measurements of host physiology and viability, with 2 strains of M. polaris and the virus MpoV-45T under 3 light intensities (5, 60 and 160 μmol quanta m −2 s −1 ), 2 light period regimes (16:8 and 24:0 h light:dark cycle) and 2 temperatures (3 and 7 °C). Our results show that low light intensity (16:8 h light:dark) delayed the decline in photosynthetic efficiency and cell lysis, while decreasing burst size by 46%. In contrast, continuous light (24:0 h light:dark) shortened the latent period by 5 h for all light intensities, and even increased the maximum virus production rate and burst size under low light (by 157 and 69%, respectively). Higher temperature (7 °C vs 3 °C) led to earlier cell lysis and increased burst size (by 19%), except for the low light conditions. These findings demonstrate the ecological importance of light in combination with temperature as a controlling factor for Arctic phytoplankton host and virus dynamics seasonally, even more so in the light of global warming.