Abstract: During a month-long study in Sanya Bay, we examined the temporal dynamics of zooplankton grazing and viral lysis rates in prokaryotes. Findings revealed that prokaryotic growth rate (μ) surpassed the combined rates of viral lysis (m_v) and zooplankton grazing (m_g), averaging 2.69±0.66d^-1 (1.61~3.87d^-1). The viral lysis rate averaged 0.77±0.34d^-1 (0.31~1.21d^-1), while the zooplankton grazing rate averaged 0.83±0.58d^-1 (0.12~1.88d^-1). Viral lysis carbon (C_i(v)) and zooplankton grazing carbon (C_i(g)) in prokaryotes were equivalent, each approximating 10⁶ fg·C·mL^-1. Negative correlations were observed between viral lysis rate and zooplankton grazing rate, as well as between viral lysis percentage (P_i(v)) and zooplankton grazing percentage (P_i(g)). Conversely, a significant positive correlation was noted between viral lysis carbon and zooplankton grazing carbon. Viral lysis and microzooplankton grazing exhibited substantial variability over the study period, with both processes contributing equally to prokaryotic mortality, highlighting their significance in prokaryotic carbon flux.

Key words: Picophytoplankton, Prokaryotes, Carbon flux, Viral lysis, Zooplankton grazing