Physiological responses ofOxyrrhis marinato a diet of virally infectedEmiliania huxleyi

Abstract

The coccolithophoreEmiliania huxleyiforms some of the largest phytoplankton blooms in the ocean. The rapid demise of these blooms has been linked to viral infections.E. huxleyiabundance, distribution, and nutritional status make them an important food source for the heterotrophic protists which are classified as microzooplankton in marine food webs. In this study we investigated the fate ofE. huxleyi(CCMP 374) infected with virus strain EhV-86 in a simple predator-prey interaction. The ingestion rates ofOxyrrhis marinawere significantly lower (between 26.9 and 50.4%) when fed virus-infectedE. huxleyicells compared to non-infected cells. Despite the lower ingestion rates,O. marinashowed significantly higher growth rates (between 30 and 91.3%) when fed infectedE. huxleyicells, suggesting higher nutritional value and/or greater assimilation of infectedE. huxleyicells. No significant differences were found inO. marinacell volumes or fatty acids profiles. These results show that virally infectedE. huxleyisupport higher growth rates of single celled heterotrophs and in addition to the “viral shunt” hypothesis, viral infections may also divert more carbon to mesozooplankton grazers.