Abstract:
A decrease in the abundance of virus-like particles (VLP) by heterotrophic nanoflagellates (HNF)
was examined using size-fractionated water samples taken from a hypereutrophic pond in December
1999, and in March and July 2000. We recorded a considerable decrease in the abundance of VLP
in the 5.0
m
m filtrate relative to the 0.2–0.8
m
m filtrates. Decrease rates of VLP were reduced in a
parallel 5.0
m
m filtrate treated with cycloheximide. The loss rates of VLP in 5.0
m
m filtrate varied
in each experiment, and a high rate of loss was found when the growth rate of HNF was high. These
results suggested that HNF consumed the VLP and that HNF is an important factor for decreasing
viral abundance in freshwater environments.
