Because the patch was physically isolated in a stable column of water, it was unlikely that the fading was caused by water mixing due to currents. Nutrients such as nitrogen and phosphorus remained at fairly constant levels throughout to bloom’s life cycle, indicating they were also unlikely reasons for the patch’s fading. When the team quantitated the DNA of E. huxleyi virus (EhV), a virus specific to this species of algae, they found approximately 200 to 800 virus particles per cell (a burst size similar to what’s seen in laboratory cultures), suggesting the viral burst was responsible for algal death.