Correction: Rainer et al. The Influence of Above-Ground Herbivory on the Response of Arctic Soil Methanotrophs to Increasing CH4 Concentrations and Temperatures. Microorganisms 2021, 9, 2080

The authors wish to make the following corrections to this paper [...]

The Influence of Above-Ground Herbivory on the Response of Arctic Soil Methanotrophs to Increasing CH4 Concentrations and Temperatures

Rising temperatures in the Arctic affect soil microorganisms, herbivores, and peatland vegetation, thus directly and indirectly influencing microbial CH4 production. It is not currently known how methanotrophs in Arctic peat respond to combined changes in temperature, CH4 concentration, and vegetation. We studied methanotroph responses to temperature and CH4 concentration in peat exposed to herbivory and protected by exclosures. The methanotroph activity was assessed by CH4 oxidation rate measurements using peat soil microcosms and a pure culture of Methylobacter tundripaludum SV96, qPCR, and sequencing of pmoA transcripts. Elevated CH4 concentrations led to higher CH4 oxidation rates both in grazed and exclosed peat soils, but the strongest response was observed in grazed peat soils. Furthermore, the relative transcriptional activities of different methanotroph community members were affected by the CH4 concentrations. While transcriptional responses to low CH4 concentrations were more prevalent in grazed peat soils, responses to high CH4 concentrations were more prevalent in exclosed peat soils. We observed no significant methanotroph responses to increasing temperatures. We conclude that methanotroph communities in these peat soils respond to changes in the CH4 concentration depending on their previous exposure to grazing. This “conditioning” influences which strains will thrive and, therefore, determines the function of the methanotroph community.

Viral spillover risk in High Arctic increases with melting glaciers

While many viruses have a single natural host, host restriction can be incomplete, hereby leading to spillovers to other host species, potentially causing significant diseases as it is the case with the Influenza A, Ebola, or the SARS-CoV-2 viruses. However, such spillover risks are difficult to quantify. As climate change is rapidly transforming environments, it is becoming critical to quantify the potential for spillovers, in an unbiased manner. For this, we resorted to a metagenomics approach, and focused on two environments in the High Arctic, soil and lake sediments from Lake Hazen. We used DNA and RNA sequencing to reconstruct the lake's virosphere and its range of eukaryotic hosts, and show that spillover risk is higher in lake sediments than in soil and increased with runoff from glacier melt - a proxy for climate change. Should climate change also shift species range of potential vectors northwards, the High Arctic could become fertile ground for emerging pandemics.

Amorphous Si and Ca affect microbial community structure in arctic permafrost soils

<p>Arctic warming affects the permafrost soils in different ways. Increase soil temperature and thawing of deeper horizons modifies the release of greenhouse gases (GHG) by release of nutrients. A lot of research was done about nutrient cycling of C, N and P, but little is known about the influence of Ca and amorphous Si (ASi) on this elements. To show the potential of this two elements in the Arctic systems, we analysed the effect of ASi and Ca on microbial community structure with next generation sequencing and qPCR. We analyzed fungal and bacterial community structure in two different soils from Greenland after incubation with different levels of ASi and Ca. Microbial community reacted differently in the high Arctic (Peary Land) and low Arctic soil (Disko Island) to changing concentrations of ASi and Ca. We found a significant change with linear correlation from gram-negative to gram-positive bacteria classes with increasing Ca and/or ASi levels. Further, abundance of Ascomycota and Basidiomycota changed. We postulate this changes as an important factor for changed GHG production as potential response to modified nutrient availability.</p>