Bogs are globally important sinks of atmospheric carbon (C) due to the accumulation of partially decomposed litter that forms peat. Because bogs receive their nutrients from the atmosphere, the world-wide increase of nitrogen (N) deposition is expected to affect litter decomposition and, ultimately, the rate of C accumulation. However, the mechanism of such biogeochemical alteration remains unclear and quantification of the effect of N addition on litter accumulation has yet to be done. Here we show that seven years of N addition to a bog decreased the C:N ratio, increased the bacterial biomass and stimulated the activity of hydrolytic and oxidative enzymes in surface peat. Furthermore, N addition modified nutrient limitation of microbes during litter decomposition so that phosphorus became a primary limiting nutrient. Alteration of N release from decomposing litter affected bog water chemistry and the competitive balance between peat-forming mosses and vascular plants. We estimate that deposition of about 4 g N m-2 yr-1 will cause a mean annual reduction of fresh litter C accumulation of about 40 g m-2 primarily as a consequence of decreased litter production from peat-forming mosses. Our findings show that N deposition interacts with both above and below ground components of biodiversity to threaten the ability of bogs to act as C sinks, which may offset the positive effects of N on C accumulation seen in other ecosystems

Fungal and actinobacterial communities were analyzed together with soil chemistry and enzyme activities in order to profile the microbial diversity associated with the economically important mushroom Tricholoma matsutake. Samples of mycelium-soil aggregation (shiro) were collected from three experimental sites where sporocarps naturally formed. PCR was used to confirm the presence and absence of matsutake in soil samples. PCR-denaturing gradient gel electrophoresis (DGGE) fingerprinting and direct sequencing were used to identify fungi and actinobacteria in the mineral and organic soil layers separately. Soil enzyme activities and hemicellulotic carbohydrates were analyzed in a productive experimental site. Soil chemistry was investigated in both organic and mineral soil layers at all three experimental sites. Matsutake dominated in the shiro but also coexisted with a high diversity of fungi and actinobacteria. Tomentollopsis sp. in the organic layer above the shiro and Piloderma sp. in the shiro correlated positively with the presence of T. matsutake in all experimental sites. A Thermomonosporaceae bacterium and Nocardia sp. correlated positively with the presence of T. matsutake, and Streptomyces sp. was a common cohabitant in the shiro, although these operational taxonomic units (OTUs) did not occur at all sites. Significantly higher enzyme activity levels were detected in shiro soil. These enzymes are involved in the mobilization of carbon from organic matter decomposition. Matsutake was not associated with a particular soil chemistry compared to that of nearby sites where the fungus does not occur. The presence of a significant hemicellulose pool and the enzymes to degrade it indicates the potential for obtaining carbon from the soil rather than tree roots.

Technosols or technogenic substrates contaminated by potentially toxic elements as a result of iron mining causes not only contamination of the surrounding ecosystem but may also lead to changes of the extent, abundance, structure and activity of soil microbial community. Microbial biomass were significantly inhibited mainly by exceeding limits of potentially toxic metals as arsenic (in the range of 343–511 mg/kg), copper (in the range of 7980–9227 mg/kg), manganese (in the range of 2417–2670 mg/kg), alkaline and strong alkaline pH conditions and minimal contents of organic nutrients. All of the 14 bacterial isolates, belonged to 4 bacterial phyla, Actinobacteria, Firmicutes; β- and γ-Proteobacteria. Thirteen genera and 20 species of microscopic filamentous fungi were recovered. The most frequently found species belonged to genera Aspergillus (A. clavatus, A. niger, A. flavus, A. versicolor, Aspergillus sp.) with the dominating A. niger in all samples, and Penicillium (P. canescens, P. chrysogenum, P. spinulosum, Penicillium sp.). Fungal plant pathogens occurred in all surface samples. These included Bjerkandera adustata, Bionectria ochloleuca with anamorph state Clonostachys pseudochloleuca, Lewia infectoria, Phoma macrostoma and Rhizoctonia sp.

The aim of the study was to compare the effect of windthrow treatments established after the windstorm in 2004 on the activity of enzyme dehydrogenase (DHA) in forest topsoils. We also focused on the effect of the recent windthrow (May 2014) on the DHA in topsoil. Soil samples were collected in July 2014 from four sites in the Tatra National Park: EXT -tree trunks and wood debris extracted after the windstorm in 2004, NEX -area left for self-regeneration after the windstorm in 2004, REX -tree trunks and wood debris extracted after the windstorm (May 2014), REN -Norway spruce stand set as a control plot. We measured pH, dry weight %, soil organic matter (SOM), carbon content in microbial biomass (C bio ) and DHA. Dehydrogenase activity at studied plots was the lowest at the EXT plot and the highest values were measured at the REN plot. DHA at NEX was similar to REN suggesting comparable ecological conditions at these plots comparing to EXT. Carbon content in microbial biomass at plots reflected intensity of dehydrogenase activity in sequence EXT < REX < NEX < REN.

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