Quental-Mendes, R. Instituto Superior Tecnico, rui_mendes.maretec@taguspark.pt
Richards, K. University of Southampton, Kelvin.J.Richards@soc.soton.ac.uk
Fasham, M. J. James Rennell Division for Ocean Circulation, MJF@soc.soton.ac.uk

 
A MODEL OF VIRAL DYNAMICS IN BACTERIA AND PHYTOPLANKTON POPULATIONS OF THE OPEN OCEAN
 
We developed an epidemics model based on a compartmental ecosystem model of the upper ocean to study the role of marine viruses in ecosystem dynamics and their impact on overall biological production rates and DOC production. Viral induced collapse of plankton blooms was also investigated. The model was run over the period of ten years for the Bermuda Station "S" area. Two thousand simulations were analyzed. The effect of differing levels of contact rate, inactivation rate, decay time of inactivated viruses and sinking speed of detritus on overall production rates and biomass were investigated. Results show that marine viruses act as regulators of the size and timing of plankton blooms and are important partners in bacterial trophodynamics. The stability of the ecosystem is extremely sensitive to the contact rate between virus and host cells which provides the underlying mechanism for non-linear epidemics. Increased levels of the contact rate determine higher viral infectivity and increase viral lysis which forces phytoplankton and bacterial collapses. The model results on biological production identify bacterial viruses as the main contributor for the carbon and nitrogen fluxes into DOC and DON and show an improved fit to the observed data in comparison to previous modelling attempts without epidemics.
 
Day: Thursday, Feb. 4
Time: 11:00 - 11:15am
Location: Sweeney Center
 
Code: SS39TH1100S