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


Liu, Hanna Ken-Yuin (2011) The Abundance and Behavior of Viruses in Ancient Seawater and Modern Iron-rich Environments. Senior thesis (Major), California Institute of Technology. doi:10.7907/VTTR-HS63.


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.

Item Type:Thesis (Senior thesis (Major))
Subject Keywords:virus; banded iron formations; viral adsorption by silica
Degree Grantor:California Institute of Technology
Division:Geological and Planetary Sciences
Major Option:Geobiology
Awards:Don Shepard Award, 2008. Library Friends Senior Thesis Prize Winner, 2011. Lucy Guernsey Service Award, 2011.
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Orphan, Victoria J. (advisor)
  • Fischer, Woodward W. (co-advisor)
Group:Senior Undergraduate Thesis Prize
Thesis Committee:
  • None, None
Defense Date:2011
Additional Information:This work was supported in part by the Caltech SURF program and sponsors Carl and Shirley Larson. The study was conceived by Woodward. W. Fischer and Victoria .J. Orphan, and research was carried out in the Orphan Laboratory at the California Institute of Technology under the mentorship of W.W.F. and V.J.O. Thanks to Matthew B. Sullivan of the University of Arizona for kindly providing Syn33a phage and Seth John for his Aquil and expertise in virus flocculation.
Funding AgencyGrant Number
Carl and Shirley LarsonUNSPECIFIED
Record Number:CaltechTHESIS:06232011-131748079
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:6527
Deposited On:23 Jun 2011 21:24
Last Modified:02 Aug 2022 21:49

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