Journal of the Marine Biological Association of the United Kingdom



Research Article

Viral and bacterial assemblage covariance in oligotrophic waters of the West Florida Shelf (Gulf of Mexico)


Ian  Hewson a1p1c1, Danielle M.  Winget a2, Kurt E.  Williamson a2, Jed A.  Fuhrman a1 and K. Eric  Wommack a2
a1 Department of Biological Sciences, University of Southern California, 3616 Trousdale Pkwy AHF 107, Los Angeles, CA 90089-0371, USA
a2 University of Delaware, Delaware Biotechnology Institute, 15 Innovation Way, Newark, DE 19711, USA

Article author query
hewson i   [PubMed][Google Scholar] 
winget dm   [PubMed][Google Scholar] 
williamson ke   [PubMed][Google Scholar] 
fuhrman ja   [PubMed][Google Scholar] 
wommack ke   [PubMed][Google Scholar] 

Abstract

Viruses are hypothesized to cause enhanced diversity in bacterial communities by regulating the outcome of intertaxon competition. However, concomitant documentation of viral and bacterial assemblage composition in oligotrophic waters are rare, particularly in situ over time, and there is almost no information on the temporal variability in virioplankton assemblage composition in oligotrophic water masses. Assemblage composition of viruses (via pulsed-field gel electrophoresis, PFGE) and bacteria (via automated rRNA intergenic spacer analysis, ARISA) was compared during surface lagrangian drifter deployments in the oligotrophic Gulf of Mexico during summer 2001, 2002, and 2003. In vertical profile, viruses and bacteria both had maximum abundances in surface waters, which decreased with depth; however, the richness of their assemblages was not significantly different between depths, suggesting independence of biomass and diversity. Viral assemblages changed rapidly (0.17–0.32 Jaccard index d−1), which was similar to the rate of change in bacterial assemblages reported in surface waters. Patterns of viral and bacterial assemblage composition were significantly related (P<0.001, r=0.58 between node ranks), and both assemblages clustered primarily by year and then by depth. These cultivation-independent observations demonstrate relationships between viral and bacterial assemblages, which are dynamic in patches of open ocean water. Even at the relatively low phylogenetic resolution of the ARISA and PFGE methods, the results support the idea that viruses may influence the species composition of host assemblages.

(Published Online April 10 2006)
(Received December 14 2005)
(Accepted February 16 2006)


Correspondence:
c1 Corresponding author, e-mail: hewson@ucsc.edu
p1 Department of Ocean Sciences, University of California Santa Cruz, 1156 High Street EMS D446, Santa Cruz, CA 95064, USA