The Production And Decay Of Marine Virioplankton And Their Correlation With Environmental Factors

Viruses are the most abundant biological entities in the marine environments.Many studies had showed that viruses play an important role in marine microbial food webs and biogeochemical cycling.In this dissertation,we investigated two typical marine environments:South China Sea and western Pacific Ocean,and studied the effects of temperature increased,light change and horizontal and vertical transportion on viral production and decay to explore the role of the virus in the marine environment.Statistical results show that the low-fluorescence virus(LFV)abundance is mainly influenced by marine physicochemical factors,while the high-fluorescence virus(HFV)abundance is mainly affected by biological factors.The production of HFV and LFV are regulated by different factors.The decay rate of HFV is mainly affected by autotrophic plankton,while the decay rate of LFV may be controlled by a variety of factors.Studies show that warming and enhancing photosynthetically active radiation(PAR)can promote viral decay,and the sensitivity of LFV to increasing temperature and light is higher than that of HFV.Studies show that warming can increase the amount of viral lysis and increase the viral production.The growth rate of the viral production relative to the temperature is significantly greater than that of the viral decay rate relative to the temperature,suggesting that the future global warming will accelerate the rate of the turnover of the virus in the surface water.The studies indicate that the freshwater-seawater mixing inhibits viral production and promotes viral decay.The change of salinity has great influence on riverine viruses from freshwater and little influence on marine viruses.In the process of sedimentation,nutrients control the virus production better than temperature.,while the viral decay rate is mainly controlled by temperature.