Virus Mineralization at Low pH in the Rio Tinto, Spain

Abstract

Water and sediment samples were collected from the Rio Tinto in southwestern Spain to assess (1) the presence and diversity of viruses in an acid mine drainage system and (2) determine if relationships occur between geochemical parameters and viral abundance. Epifluroescence microscopy and transmission electron microscopy revealed that viruses are not only present, but geochemical evidence and multivariate statistical analyses suggest that viruses in the Rio Tinto participate in mineralization processes. Viral capsids and tails occurred with iron-bearing minerals sorbed to their surfaces, at times with mineralization so extensive that differentiating between viral and inorganic particles using microscopy was difficult. Moreover, a strong inverse relationship between viral abundance and jarosite saturation state (Pearson correlation coefficient r = −0.71) was observed implying that viruses were removed from suspension owing to ongoing mineral precipitation (i.e., decreasing number of viruses with increasing rates of mineral precipitation, as inferred from saturation state). Viral-mineral interactions may additionally impact virus-host relationships as a weak correlation was found between viral and prokaryotic abundance, a relationship that is usually found to be highly correlated. Viral abundance and pH were strongly correlated (Pearson correlation coefficient r = 0.94) indicating viral sensitivity to low pH conditions.

Keywords:

• bacteriophage
• acid mine drainage
• jarosite
• astrobiology

Acknowledgments

This research was made possible by support from the Swedish Foundation for International Cooperation in Research in Higher Education, Ontario Graduate Scholarship, and National Sciences and Engineering Research Council of Canada (NSERC). We would like to thank Robert Harris for his assistance on the TEM at the University of Guelph, and the two anonymous reviewers for their comments leading to the improvement of this manuscript.

Notes

*n.d. = not detected