Virioplankton in the Kara Sea: The impact of viruses on mortality of heterotrophic bacteria

• Published in: Oceanology (Washington. 1965) Vol. 55; no. 4; pp. 561 - 572
• Main Authors: Kopylov, A. I., Sazhin, A. F., Zabotkina, E. A., Romanova, N. D.
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 01.07.2015; Springer Nature B.V
• Subjects: Aquatic ecosystems; Bacteria; Earth and Environmental Science; Earth Sciences; Estuaries; Marine Biology; Marine ecology; Mortality; Oceanography; Plankton; Viruses; Kara Sea; PNE, Kara Sea; Russia, Siberia, Yenisei R; Heterotrophic Bacterium; Viral Lysis; Total Abundance; Burst Size; Viral Particle
• ISSN: 0001-4370; 1531-8508
• DOI: 10.1134/S0001437015040104

Studies were conducted in shallow and deepwater areas of the Kara Sea. The abundance of bacteria ( N B ) and the abundance of viruses ( N V ) ranged within (19.4–2215.1) × 10 3 cells/ml and (97.6–5796.8) × 10 3 particles/ml, respectively. The virus to bacteria ratio varied from 1.4 to 29.1. A positive correlation was found between N B and N V ( R = 0.87, n = 45, p = 0.05. Using electron transmission microscopy it was detected that the frequency of visibly infected cells of bacteria (FVIC) varied from 0.2 to 1.9% of N B . The maximum values of FVIC were recorded in the estuary of the Yenisei River. The infected cells of bacteria contained from 4 to 127 (an average of 12) phages/cell of mature viruses. Virus-mediated mortality of bacteria was 0.5% and varied from 1.4 to 16.1% of the total mortality of bacterioplankton. This indicates a minor role of viruses in the control of overabundance and production of bacterioplankton in the Kara Sea during the surveyed period.