Change in Emiliania huxleyi Virus Assemblage Diversity but Not in Host Genetic Composition during an Ocean Acidification Mesocosm Experiment

• Published in: Viruses
• Main Authors: Highfield, A., Joint, I., Gilbert, J.A., Crawfurd, K.J., Schroeder, D.C.
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2017
• Subjects: Emiliania huxleyi; Ocean acidification
• Online Access: https://www.vliz.be/imisdocs/publications/32/301132.pdf

Effects of elevated pCO2 on Emiliania huxleyi genetic diversity and the viruses that infectE. huxleyi (EhVs) have been investigated in large volume enclosures in a Norwegian fjord. Triplicateenclosures were bubbled with air enriched with CO2 to 760 ppmv whilst the other three enclosureswere bubbled with air at ambient pCO2; phytoplankton growth was initiated by the addition of nitrateand phosphate. E. huxleyi was the dominant coccolithophore in all enclosures, but no difference ingenetic diversity, based on DGGE analysis using primers specific to the calcium binding protein gene(gpa) were detected in any of the treatments. Chlorophyll concentrations and primary productionwere lower in the three elevated pCO2 treatments than in the ambient treatments. However, althoughcoccolithophores numbers were reduced in two of the high-pCO2 treatments; in the third, there was nosuppression of coccolithophores numbers, which were very similar to the three ambient treatments.In contrast, there was considerable variation in genetic diversity in the EhVs, as determined byanalysis of the major capsid protein (mcp) gene. EhV diversity was much lower in the high-pCO2treatment enclosure that did not show inhibition of E. huxleyi growth. Since virus infection is generallyimplicated as a major factor in terminating phytoplankton blooms, it is suggested that no study ofthe effect of ocean acidification in phytoplankton can be complete if it does not include an assessmentof viruses.