The impacts of long-term polycyclic aromatic hydrocarbons (PAHs) and heavy metal pollution on soil microbial communities functioning were studied in soils taken from an old coke plant. The concentrations of PAHs in the tested soils ranged from 171 to 2137 mg kg-1. From the group of tested heavy metals, concentrations of lead were found to be the highest, ranging from 57 to 3478 mg kg-1, while zinc concentrations varied from 247 to 704 mg kg-1 and nickel from 10 to 666 mg kg-1. High dehydrogenase, acid and alkaline phosphatase activities were observed in the most contaminated soil. This may indicate bacterial adaptation to long-term heavy metal and hydrocarbon contamination. However, the Community Level Physiological Profiles (CLPPs) analysis showed that the microbial functional diversity was reduced and influenced to a higher extent by some metals (Pb, Ni), moisture and conductivity than by PAHs.

The subject of the paper is the analysis of the relationship between spontaneous vegetation diversity and soil respiration in novel post-coal mine ecosystem. In the natural and semi-natural ecosystems, soil respiration process (Rs) is a crucial ecosystem function regulating terrestrial ecosystems’ carbon cycle. Soil respiration depends on the quality and quantity of the soil organic matter (SOM), the soil microbes’ activity, and root metabolism. The listed factors are directly related to the composition diversity of vegetation plant species (biochemistry). For many years, soil respiration parameters have been studied in natural and seminatural vegetation communities and ecosystems. However, there still need to be a greater understanding of the relationship between vegetation plant species diversity and soil respiration as a crucial ecosystem function. Plant species diversity has to be analysed through both the taxonomic diversity and the functional diversity. These approaches reflect the composition, structure, and function of plant species communities. We hypothesise that the diversity of the spontaneous vegetation species composition shapes the amount of soil respiration in a post-coal mine novel ecosystem. The soil respiration differs significantly along the vegetational types driven by habitat gradients and is significantly higher in highly functional richness and dispersion vegetation patches. Contrary to our expectation, soil respiration was the highest in the less diverse vegetation types – both taxonomical and functional evenness were non-significant factors. Only functional dispersion is weakly negative correlated with soil respiration level (SRL).