The Abundance and Behavior of Viruses in Ancient Seawater and Modern Iron-rich Environments

Author: Liu, Hanna Ken-Yuin

Year: 2011

Degree: Senior thesis (Major)

Advisors: Orphan, Victoria J.; Fischer, Woodward W.

Committee Member: None, None

Option: Geobiology

DOI: 10.7907/VTTR-HS63

Abstract

The proclivity of silica for ferric hydroxide sorption sites allows for an Archean iron cycle involving iron-silica co-precipitation and deposition of banded iron formations (BIF). Considering the tendency of viruses to also sorb iron, here we investigate the possibility that viruses were involved in the iron cycle and potentially deposited in BIFs. A known concentration of Syn33a cyanophages was introduced into each media and the viral particles remaining in solution after a short centrifugation were enumerated using epifluorescence microscopy. The number of particles sequestered on the siliceous ferric oxide precipitate was estimated by difference. Similar to previous experiments, we observed a strong affinity of viral particles for iron oxides in the absence of silica. However, we also observe competitive inhibition of viral adsorption by silica, though only when silica is raised to concentrations of 670 μM. Ultimately, our data reveal that interactions between iron, silica, and viruses would have affected virus dynamics and corresponding biogeochemistry in the Archean ocean. Similar dynamics are predicted to occur in iron-rich environments today.

Files