Viruses in Antarctic ecosystems

Pearce, David A.; Wilson, William H.

doi:10.1017/s0954102003001330

Cited by 26 publications

(22 citation statements)

References 121 publications

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“…These groups are represented by the same taxonomical groupings oceanwide. Bacteriophages (viruses) exert effective control on bacterial numbers, also in the SO (Marchant et al 2000, Pearce & Wilson 2003. The relative roles of pathogens and predators in constraining bacterial numbers will vary but there is little doubt that both will be working in tandem (Pearce & Wilson 2003).…”

Section: Microbial Networkmentioning

confidence: 99%

The role of grazing in structuring Southern Ocean pelagic ecosystems and biogeochemical cycles

2004

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This review examines the links between pelagic ecology and ocean biogeochemistry with an emphasis on the role of the Southern Ocean in global cycling of carbon and silica. The structure and functioning of pelagic ecosystems is determined by the relationship between growth and mortality of its species populations. Whereas the key role of iron supply in conditioning the growth environment of landremote oceans is now emerging, the factors shaping the mortality environment are still poorly understood. This paper addresses the role of grazing as a selective force operating on the structure and functioning of pelagic ecosystems within the larger conceptual framework of evolutionary ecology. That mortality due to grazing decreases with increasing cell size is widely taken for granted. We examine the impact of this principle across the range of size classes occupied by Southern Ocean plankton and show that relatively few species play crucial roles in the trophic structure and biogeochemical cycles of the Southern Ocean. Under iron-sufficient conditions, high growth rates of weakly silicified diatoms and Phaeocystis result in build-up of blooms that fuel "the food chain of the giants" (diatoms-krill-whales) and drive the carbon pump. In contrast, high grazing pressure of small copepods and salps on the regenerating microbial communities characteristic of the iron-limited Southern Ocean results in accumulation of large, heavily silicified diatoms that drive the silicon pump. The hypotheses we derive from field observations can be tested with in situ iron fertilization experiments.

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Section: Microbial Networkmentioning

confidence: 99%

The role of grazing in structuring Southern Ocean pelagic ecosystems and biogeochemical cycles

2004

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“…Information on viruses in aquatic environments in the polar regions is still scarce [ Pearce and Wilson , 2003], especially in freshwaters. However, recent investigations in both freshwater and saline Antarctic lakes have revealed that freshwater systems operate in a distinctly different way to saline systems [ Lisle and Priscu , 2004; Madan et al , 2005; Laybourn‐Parry et al , 2007].…”

Section: Introductionmentioning

confidence: 99%

Viral dynamics in cryoconite holes on a high Arctic glacier (Svalbard)

et al. 2007

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[1] Viruses are an abundant and dynamic constituent of microbial communities in aquatic ecosystems. In this study we characterized the abundance of viruses associated first with the bottom sediment and overlying water of cryoconite holes and second with shallow ice cores of two different glaciers in Svalbard. Viral abundances were ca. 10-100 times lower than the average for marine and freshwater ecosystems in temperate regions. Virus to bacterium ratios (VBR) (average > 10, range between 0.7 and 74 in the water and ice samples) and a strong positive correlation between viral and bacterial abundance (r = 0.93, p < 0.01, N = 57) indicate that viruses most probably play an important role in controlling bacterial mortality and hence biogeochemical cycling on glaciers. Samples taken along a transect from the glacier ablation area to proglacial ponds in its forefield showed that viral abundance increased in response to a higher host availability, which in turn probably resulted from an increase in temperature and higher mineral levels in the ponds. In a transplantation experiment, viruses from cryoconite holes were incubated with a bacterial community from a proglacial lake. Results from the transplantation experiment showed that viruses from cryoconite holes were able to infect bacteria from proglacial lakes and thus influence biogeochemical cycles across different glacial ecosystems. Our data therefore suggest that viruses in cryoconite holes may be able to infect a broad range of bacterial species.

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“…Despite the extreme conditions in the Antarctic, such as low temperature, high salinity, osmotic stress and high doses of UV radiation, microorganisms (includ− ing viruses, bacteria and fungi) are the most numerous groups of organisms that colonize diverse habitats (Abyzov 1993;Pearce and Wilson 2003;Onofri et al 2007;Ruisi et al 2007;Finster 2008). Among them, fungi are represented by in− digenous species, including endemic species found only in the Antarctic, and show a variety of physiological and morphological adaptations to survive in such ex− treme conditions (Robinson 2001).…”

Section: Introductionmentioning

confidence: 99%

An analysis of fungal propagules transported to the Henryk Arctowski Antarctic Station

Augustyniuk-Kram¹,

Chwedorzewska²,

Korczak−Abshire³

et al. 2013

Polish Polar Research

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During three austral summer seasons, dust and soil from clothes, boots and equip− ment of members of scientific expeditions and tourists visiting the Polish Antarctic Station Henryk Arctowski were collected and analysed for the presence of fungal propagules. Of a to− tal of 60 samples, 554 colonies of fungi belonging to 19 genera were identified. Colonies of the genus Cladosporium, Penicillium and non−sporulating fungus (Mycelia sterilia) domi− nated in the examined samples. The microbiological assessment of air for the presence of fungi was also conducted at two points in the station building and two others outside the sta− tion. A total of 175 fungal colonies belonging to six genera were isolated. Colonies of the ge− nus Penicillium were the commonest in the air samples. The potential epidemiological conse− quences for indigenous species as a result of unintentional transport of fungal propagules to the Antarctic biome are discussed in the light of rapid climate change in some parts of the Ant− arctic and adaptation of fungi to extreme conditions.

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Viruses in Antarctic ecosystems

Cited by 26 publications

References 121 publications

The role of grazing in structuring Southern Ocean pelagic ecosystems and biogeochemical cycles

The role of grazing in structuring Southern Ocean pelagic ecosystems and biogeochemical cycles

Viral dynamics in cryoconite holes on a high Arctic glacier (Svalbard)

An analysis of fungal propagules transported to the Henryk Arctowski Antarctic Station

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