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Are viruses important in the plankton of highly turbid glacier-fed lakes?

Drewes F, Peter H, Sommaruga R - Sci Rep (2016)

Bottom Line: In the glacier-fed turbid lakes, VLP abundance increased with distance to the glacier, but the highest numbers were observed in the clear lake by the end of August, coinciding with the maximum in prokaryotic abundance.Our results suggest that viral loss by attachment to particles is less important than expected.Nevertheless, the relatively lower variability in VLP abundance and the lower virus-to-prokaryote ratio found in the turbid lakes than in the clear one point to a rather low temporal turnover and thus, to a reduced impact on microbial communities.

View Article: PubMed Central - PubMed

Affiliation: University of Innsbruck, Institute of Ecology, Lake and Glacier Research Group, Technikerstr. 25, 6020 Innsbruck, Austria.

ABSTRACT
Viruses are ubiquitous in aquatic ecosystems where they significantly contribute to microbial mortality. In glacier-fed turbid lakes, however, viruses not only encounter low host abundances, but also a high number of suspended mineral particles introduced by glacier meltwaters. We hypothesized that these particles potentially lead to unspecific adsorption and removal of free virus from the plankton, and thus significantly reduce their abundance in this type of lake. We followed the distribution of free virus-like particles (VLP) during the ice-free season across a turbidity gradient in four alpine lakes including one adjacent clear system where hydrological connectivity to the receding glacier is already lost. In the glacier-fed turbid lakes, VLP abundance increased with distance to the glacier, but the highest numbers were observed in the clear lake by the end of August, coinciding with the maximum in prokaryotic abundance. Our results suggest that viral loss by attachment to particles is less important than expected. Nevertheless, the relatively lower variability in VLP abundance and the lower virus-to-prokaryote ratio found in the turbid lakes than in the clear one point to a rather low temporal turnover and thus, to a reduced impact on microbial communities.

No MeSH data available.


Related in: MedlinePlus

Changes in virus-like particle (VLP) abundance throughout the ice-free season.Shown are all measured samples (i.e., different depths) at four times of the year in the four Faselfad lakes. Values on x-axis are jittered for clarity.
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f2: Changes in virus-like particle (VLP) abundance throughout the ice-free season.Shown are all measured samples (i.e., different depths) at four times of the year in the four Faselfad lakes. Values on x-axis are jittered for clarity.

Mentions: Significant changes in VLP abundance were observed among the lakes over the ice-free season (ANOVA F3,120 = 30.8; p < 0.01, Fig. 2). The highest VLP abundance was observed in the clear lake FAS 4 at 14 m depth, on August 1 (1.25 × 107 VLP mL−1), whereas the lowest abundance was observed in FAS 1 at 4 m depth on July 17 (4.38 × 105 VLP mL−1). Considering all four lakes, the lowest VLP abundance was recorded at the beginning of the season soon after the ice cover disappeared (Fig. 2). Later in the season, the average VLP abundance increased in all lakes reaching a maximum in late August. Towards the end of the ice-free season in October, mean VLP abundance decreased again. However, this reduction was mainly observable in the clear lake FAS 4, while VLP abundance remained rather constant in the turbid lakes (Fig. 2). Throughout the season, FAS 1 had on average the lowest VLP abundance compared to the other lakes. Within each lake, VLP abundance was significantly different over the season (FAS 1: ANOVA F3,16 = 7.64, p < 0.01; FAS 3: ANOVA F3,36 = 114.4, p < 0.01; FAS 4 unequal variance Welch F test F16,14 = 40.56, p < 0.01, and FAS 6 ANOVA F3,24 = 16.95, p < 0.01).


Are viruses important in the plankton of highly turbid glacier-fed lakes?

Drewes F, Peter H, Sommaruga R - Sci Rep (2016)

Changes in virus-like particle (VLP) abundance throughout the ice-free season.Shown are all measured samples (i.e., different depths) at four times of the year in the four Faselfad lakes. Values on x-axis are jittered for clarity.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4837353&req=5

f2: Changes in virus-like particle (VLP) abundance throughout the ice-free season.Shown are all measured samples (i.e., different depths) at four times of the year in the four Faselfad lakes. Values on x-axis are jittered for clarity.
Mentions: Significant changes in VLP abundance were observed among the lakes over the ice-free season (ANOVA F3,120 = 30.8; p < 0.01, Fig. 2). The highest VLP abundance was observed in the clear lake FAS 4 at 14 m depth, on August 1 (1.25 × 107 VLP mL−1), whereas the lowest abundance was observed in FAS 1 at 4 m depth on July 17 (4.38 × 105 VLP mL−1). Considering all four lakes, the lowest VLP abundance was recorded at the beginning of the season soon after the ice cover disappeared (Fig. 2). Later in the season, the average VLP abundance increased in all lakes reaching a maximum in late August. Towards the end of the ice-free season in October, mean VLP abundance decreased again. However, this reduction was mainly observable in the clear lake FAS 4, while VLP abundance remained rather constant in the turbid lakes (Fig. 2). Throughout the season, FAS 1 had on average the lowest VLP abundance compared to the other lakes. Within each lake, VLP abundance was significantly different over the season (FAS 1: ANOVA F3,16 = 7.64, p < 0.01; FAS 3: ANOVA F3,36 = 114.4, p < 0.01; FAS 4 unequal variance Welch F test F16,14 = 40.56, p < 0.01, and FAS 6 ANOVA F3,24 = 16.95, p < 0.01).

Bottom Line: In the glacier-fed turbid lakes, VLP abundance increased with distance to the glacier, but the highest numbers were observed in the clear lake by the end of August, coinciding with the maximum in prokaryotic abundance.Our results suggest that viral loss by attachment to particles is less important than expected.Nevertheless, the relatively lower variability in VLP abundance and the lower virus-to-prokaryote ratio found in the turbid lakes than in the clear one point to a rather low temporal turnover and thus, to a reduced impact on microbial communities.

View Article: PubMed Central - PubMed

Affiliation: University of Innsbruck, Institute of Ecology, Lake and Glacier Research Group, Technikerstr. 25, 6020 Innsbruck, Austria.

ABSTRACT
Viruses are ubiquitous in aquatic ecosystems where they significantly contribute to microbial mortality. In glacier-fed turbid lakes, however, viruses not only encounter low host abundances, but also a high number of suspended mineral particles introduced by glacier meltwaters. We hypothesized that these particles potentially lead to unspecific adsorption and removal of free virus from the plankton, and thus significantly reduce their abundance in this type of lake. We followed the distribution of free virus-like particles (VLP) during the ice-free season across a turbidity gradient in four alpine lakes including one adjacent clear system where hydrological connectivity to the receding glacier is already lost. In the glacier-fed turbid lakes, VLP abundance increased with distance to the glacier, but the highest numbers were observed in the clear lake by the end of August, coinciding with the maximum in prokaryotic abundance. Our results suggest that viral loss by attachment to particles is less important than expected. Nevertheless, the relatively lower variability in VLP abundance and the lower virus-to-prokaryote ratio found in the turbid lakes than in the clear one point to a rather low temporal turnover and thus, to a reduced impact on microbial communities.

No MeSH data available.


Related in: MedlinePlus