Viruses in Antarctic lakes

Abstract

Water samples collected from four perennially ice‐covered Antarctic lakes during the austral summer of 1996–1997 contained high densities of extracellular viruses. Many of these viruses were found to be morphologically similar to double‐stranded DNA viruses that are known to infect algae and protozoa. These constitute the first observations of viruses in perennially ice‐covered polar lakes. The abundance of planktonic viruses and data suggesting substantial production potential (relative to bacterial secondary and photosynthetic primary production) indicate that viral lysis may be a major factor in the regulation of microbial populations in these extreme environments. Furthermore, we suggest that Antarctic lakes may be a reservoir of previously undescribed viruses that possess novel biological and biochemical characteristics.

High control of bacterial production by viruses in a eutrophic oxbow lake

“…Hence, not all loss factors occurring in situ could be considered in the decay method. Finally, it should be mentioned that bottle incubations might affect viral production as well (Kepner et al 1998).…”

Tangential flow diafiltration: an improved technique for estimation of virioplankton production

“…Approaches to estimation of VP have been numerous and include electron microscopic observation of the frequency of visibly infected cells (FVIC) (Proctor et al 1993, Steward et al 1996, Binder 1999, Guixa-Boixereu et al 1999, Hwang & Cho 2002, Middelboe et al 2002, Choi et al 2003, Weinbauer et al 2003a, contact rates of viruses and bacteria (Murray & Jackson 1992, Suttle & Chan 1994, incorporation of 3 H-thymidine or 32 P into viral DNA (Steward et al 1992a, Fuhrman & Noble 1995, Kepner et al 1998), viral decay rates (Heldal & Bratbak 1991, Bratbak et al 1992, Guixa-Boixereu et al 1999, Tuomi & Kuuppo 1999, fluorescently labeled viruses (FLVs) as tracers of viral decay and VP (Noble & Fuhrman 2000, Helton et al 2005, this issue), and dilution methods (Wilhelm et al 2002, Winter et al 2004a, Helton et al 2005. The assumptions, advantages, and disadvantages of each of these approaches to measuring VP are summarized in Table 1.…”

Experimental fossilisation of viruses from extremophilic Archaea

“…Nevertheless, it has already allowed the identification of several thousands of viruses having different morphologies and characteristics, and also of new virus families (see review in Le Romancer et al, 2007). Viruses have been identified in all known extreme environments: hypersaline (Oren et al, 1997;Dyall-Smith et al, 2003;Pagaling et al, 2007;Sime-Ngando et al, 2010), alkaline lakes (Jiang et al, 2004), deserts (Prigent et al, 2005), polar regions (Maranger et al, 1994;Kepner et al, 1998;Borriss et al, 2003;Gowing, 2003), acid mine drainages (Kyle et al, 2008a), deep subsurface rocks (Bird et al, 2001;Kyle et al, 2008b), and in hydrothermal environments. The search for new viruses in the latter environment has been especially fruitful, following the pioneering work of Wolfram Zillig on the viruses of hyperthermophilic Archaea (Martin et al, 1984;Rice et al, 2001;Rachel et al, 2002).…”