Microorganisms (Nov 2021)

Effects of UV Radiation on the Chlorophyte <i>Micromonas polaris</i> Host–Virus Interactions and MpoV-45T Virus Infectivity

  • Charlotte Eich,
  • Sven B. E. H. Pont,
  • Corina P. D. Brussaard

DOI
https://doi.org/10.3390/microorganisms9122429
Journal volume & issue
Vol. 9, no. 12
p. 2429

Abstract

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Polar seas are under threat of enhanced UV-radiation as well as increasing shipping activities. Considering the ecological importance of marine viruses, it is timely to study the impact of UV-AB on Arctic phytoplankton host–virus interactions and also test the efficacy of ballast water (BW) UV-C treatment on virus infectivity. This study examined the effects of: (i) ecologically relevant doses of UV-AB radiation on Micromonas polaris RCC2258 and its virus MpoV-45T, and (ii) UV-C radiation (doses 25–800 mJ cm−2) on MpoV-45T and other temperate algal viruses. Total UV-AB exposure was 6, 12, 28 and 48 h (during the light periods, over 72 h total). Strongest reduction in algal growth and photosynthetic efficiency occurred for 28 and 48 h UV-AB treatments, and consequently the virus production rates and burst sizes were reduced by more than half (compared with PAR-only controls). For the shorter UV-AB exposed cultures, negative effects by UV (especially Fv/Fm) were overcome without impacting virus proliferation. To obtain the BW desired log−4 reduction in virus infectivity, a UV-C dose of at least 400 mJ cm−2 was needed for MpoV-45T and the temperate algal viruses. This is higher than the commonly used dose of 300 mJ cm−2 in BW treatment.

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