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Ore mining and processing have greatly altered ecosystems, often limiting their capacity to provide ecosystem services critical to our survival. The soil environments of two abandoned uranium mines were chosen to analyze the effects of long-term uranium and heavy metal contamination on soil microbial communities using dehydrogenase and phosphatase activities as indicators of metal stress. The levels of soil contamination were low, ranging from 'precaution' to 'moderate', calculated as Nemerow index. Multivariate analyses of enzyme activities revealed the following: (i) spatial pattern of microbial endpoints where the more contaminated soils had higher dehydrogenase and phosphatase activities, (ii) biological grouping of soils depended on both the level of soil contamination and management practice, (iii) significant correlations between both dehydrogenase and alkaline phosphatase activities and soil organic matter and metals (Cd, Co, Cr, and Zn, but not U), and (iv) multiple relationships between the alkaline than the acid phosphatase and the environmental factors. The results showed an evidence of microbial tolerance and adaptation to the soil contamination established during the long-term metal exposure and the key role of soil organic matter in maintaining high microbial enzyme activities and mitigating the metal toxicity. Additionally, the results suggested that the soil microbial communities are able to reduce the metal stress by intensive phosphatase synthesis, benefiting a passive environmental remediation and provision of vital ecosystem services.

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Antarctica remains one of the last areas, where direct human impact is limited. Compared to the rest of the world Antarctic environment could be considered as unpolluted. This explains the significant scientific interest to the effects of touristic activities, and especially during the last decade due to the increased number of tourists visiting diverse parts of the continent. The role of human activity for Salmonella presence in penguins remains unclear. The aim of the present study was to contribute to the knowledge to what extend Salmonella presence in penguins interstitial fauna might be used as an indicator of direct or indirect human impact on the Antarctic ecosystem, by investigating three Gentoo colonies, subjected to different levels of human impact. 16 individual fecal samples were taken per each Gentoo colony. The potentially pathogenic Salmonella typhimurium/enteridis occurred in both studied populations at King George Island at the rates 37,5% and 18,8% respectively, or at rates 85,7% and 60,0% of the positive for Salmonella sp. samples respectively. Unlike both populations at Admiralty bay, King George Island, all samples taken from the Caleta Argentina population at Livingston Island were positive neither for both pathogenic species nor for Salmonell sp.