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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

Virus-like particle (VLP) abundance across the turbidity gradient including all measured samples.Colors codes are the same as in Fig. 2.
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f3: Virus-like particle (VLP) abundance across the turbidity gradient including all measured samples.Colors codes are the same as in Fig. 2.

Mentions: Throughout the season, FAS 1 was the most turbid lake (ranging between 6.2 and 49.2 NTU), followed by FAS 3 (3.4 to 11.2 NTU), and FAS 6 (1.3 to 6.3 NTU) (Supplementary Table S1). The highest turbidity was measured by the end of August for all three turbid lakes, whereas the lowest values for FAS 3 and 6 were measured in early August, and in mid-July for FAS 1. Lake FAS 4 had very low turbidity over the entire season. There was a significant, but weak negative correlation between turbidity and VLP abundance across the turbidity gradient (correlation for all lakes: R = −0.22, p = 0.02, Fig. 3). However, when the data from FAS 4 were excluded, no significant correlation was found (R = −0.20, p = 0.08). Even under extremely turbid conditions on August 28 (range: 44.2 to 58.7 NTU within the water column), VLP abundances in FAS 1 reached similar levels than under considerably lower particle loads (e.g., 13.6 and 23.3 NTU).


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

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

Virus-like particle (VLP) abundance across the turbidity gradient including all measured samples.Colors codes are the same as in Fig. 2.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f3: Virus-like particle (VLP) abundance across the turbidity gradient including all measured samples.Colors codes are the same as in Fig. 2.
Mentions: Throughout the season, FAS 1 was the most turbid lake (ranging between 6.2 and 49.2 NTU), followed by FAS 3 (3.4 to 11.2 NTU), and FAS 6 (1.3 to 6.3 NTU) (Supplementary Table S1). The highest turbidity was measured by the end of August for all three turbid lakes, whereas the lowest values for FAS 3 and 6 were measured in early August, and in mid-July for FAS 1. Lake FAS 4 had very low turbidity over the entire season. There was a significant, but weak negative correlation between turbidity and VLP abundance across the turbidity gradient (correlation for all lakes: R = −0.22, p = 0.02, Fig. 3). However, when the data from FAS 4 were excluded, no significant correlation was found (R = −0.20, p = 0.08). Even under extremely turbid conditions on August 28 (range: 44.2 to 58.7 NTU within the water column), VLP abundances in FAS 1 reached similar levels than under considerably lower particle loads (e.g., 13.6 and 23.3 NTU).

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