Artur Banach

The interaction between decomposition, net n and p mineralization and their mobilization to the surface water in fens

Worldwide, fens and peat lakes that used to be peat-forming systems have become a significant source of C, N and P due to increased peat decomposition. To test the hypothesis that net nutrient mineralization rates may be uncoupled from decomposition rates, we investigated decomposition and net mineralization rates of nutrients in relation to sediment and pore water characteristics. We incubated 28 non-calcareous peat sediments and floating fen soils under aerobic and anaerobic conditions. We also tried to find a simple indicator to estimate the potential nutrient mobilization rates from peat sediments to the water layer by studying their relation with sediment and pore water characteristics in 44 Dutch non-calcareous peat lakes and ditches. Decomposition rates were primarily determined by the organic matter content, and were higher under aerobic conditions. However, highly decomposed peat sediments with low C:P and C:N ratios still showed high net nutrient mineralization rates. At Fe:PO(4) ratios below 1molmol(-1), PO(4) mobilization from the sediment to the water layer was considerable and linearly related to the pore water PO(4) concentration. At higher ratios, there was a strong linear correlation between the Fe:PO(4) ratio and PO(4) mobilization. Hence, measuring Fe and PO(4) in anaerobic sediment pore water provides a powerful tool for a quick assessment of internal PO(4) fluxes. Mobilization of mineral N was largely determined by diffusion. Total sediment Fe:S ratios gave an important indication of the amount of Fe that is available to immobilize PO(4). Pore water Fe concentrations decreased at ratios <1molmol(-1), whereas pore water PO(4) concentrations and PO(4) mobilization to the water layer increased. As PO(4) mobilization rates from the sediment to the water layer contribute to almost half of the total P load in Dutch peat lakes and fens, it is of pivotal importance to examine the magnitude of internal fluxes. Dredging of the nutrient-rich upper sediment layer will only be a useful restoration measure if both the influx of P-rich water and its internal mobilization from the newly exposed, potentially more reactive peat layer are sufficiently low.

Potential for Aerobic Methane Oxidation in Carboniferous Coal Measures

Carbon (C), geologically sequestered in coal, is gradually released to the atmosphere as CH4 and CO2. Recent anthropogenic activity (coal mining) has rapidly increased the rate of C reallocation from coal deposits into the atmosphere, which has deleterious effect on the climate as both gases are effective infrared absorbers. In the current study we demonstrate that the coal bearing sedimentary rocks possess potential of biological methane oxidation. Viable methanotrophic bacteria, capable of methane oxidation at ambient air and a range of methane concentrations were found in coalbearing formations of the Upper Silesian (USCB) and Lublin Coal Basins (LCB). Factors controlling activity of the aerobic methanotrophic bacteria in the deep subsurface such as, depth, methane concentration, available electron acceptors, moisture and nutrients availability were investigated along with paleoenvironmental factors (temperature changes during and after burial and paleohydrological infiltration). The distribution and activity of the methanotrophic bacteria in the deep subsurface were found to be influenced by geological conditions among which evolution of paleotemperatures and paleohydrological conditions play a predominant role. The data presented along with analysis of molecular composition of the coalbed gases in various coal basins worldwide has led to the conclusion that aerobic methanotrophy may be a widespread process, which, to our knowledge, so far has not been included in investigations concerning C cycling in the subsurface.

Methane Oxidation by Endophytic Bacteria Inhabiting Sphagnum sp. and Some Vascular Plants

Methane emission from wetlands is responsible for about 24% of the total CH4 emissions. The value of emission is a result of the balance between the processes of methane formation (methanogenesis) and sinks (methanotrophy). The methanotrophic activity from well-aerated soil surface layers has been relatively well recognized. On the contrary, the active role of plants in reduction of methane emission is rather not fully known. The association of methanotrophic bacteria with plants of Sphagnum spp., has already been recognized. In our investigations, particular attention was paid to vascular plants from a peatland overgrown by Sphagnum spp. but also Eriophorum vaginatum, Carex nigra, and Vaccinium oxycoccos. The gases emitted from the surface of Moszne peatland were collected using the chamber method from selected sites during growing seasons (spring, summer, autumn). To estimate the contribution of plants in methane emissions from the peatland, in each investigated site gas was sampled from the surface with the native flora cover and after removal thereof. Our results show that the reduction in the CH4 emission was related to the plant composition, vegetation period, and conditions of the plants. It was confirmed that the endophytes under investigation belonged to type I methanotrophs.

Easily degradable carbon – an indicator of microbial hotspots and soil degradation

Abstract The effect of arable soil was quantified against non-cultivated soil on easily degradable carbon and other selected microbiological factors, i.e. soil microbial biomass, respiration activity, and dehydrogenase activity. The intent was to ascertain whether easily degradable carbo can be useful as a sensitive indicator of both soil biological degradation and microbial hot-spots indication. As a result, it was found that soil respiration activity was significantly higher (p <0.0001) in all controls, ranging between 30-60 vs. 11.5-23.7 μmol CO2 kg d.m.−1 h−1 for the arable soils. Dehydrogenase activity was significantly lower in the arable soil (down to 35-40% of the control values, p <0.001) varying depending on the soil type. The microbial biomass was also significantly higher at the non-cultivated soil (512-2807 vs. 416-1429 µg g−1 d.m., p <0.001), while easily degradable carbon ranged between 620-1209 mg kg−1 non-cultivated soil and 497-877 mg kg−1 arable soil (p <0.0001). It was demonstrated that agricultural practices affected soil properties by significantly reducing the levels of the studied parameters in relation to the control soils. The significant correlations of easily degradable carbon-respiration activity (ρ = 0.77*), easily degradable carbon-dehydrogenase activity (ρ = 0.42*), and easily degradable carbon-microbial biomass (ρ = 0.53*) reveal that easily degradable carbon is a novel, suitable factor indicative of soil biological degradation. It, therefore, could be used for evaluating the degree of soil degradation and for choosing a proper management procedure.

Community-level physiological profiles of microorganisms inhabiting soil contaminated with heavy metals

Abstract The aim of the study was to assess the differences in the bacterial community physiological profiles in soils contaminated with heavy metals versus soils without metal contaminations. The study’s contaminated soil originated from the surrounding area of the Szopienice non-ferrous metal smelter (Silesia Region, Poland). The control was soil unexposed to heavy metals. Metal concentration was appraised by flame atomic absorption spectrometry, whereas the the community-level physiological profile was determined with the Biolog EcoPlatesTM system. The soil microbiological activity in both sites was also assessed via dehydrogenase activity. The mean concentrations of metals (Cd and Zn) in contaminated soil samples were in a range from 147.27 to 12265.42 mg kg−1, and the heavy metal contamination brought about a situation where dehydrogenase activity inhibition was observed mostly in the soil surface layers. Our results demonstrated that there is diversity in the physiological profiles of microorganisms inhabiting contaminated and colntrol soils; therefore, for assessment purposes, these were treated as two clusters. Cluster I included colntrol soil samples in which microbial communities utilised most of the available substrates. Cluster II incorporated contaminated soil samples in which a smaller number of the tested substrates was utilised by the contained microorganisms. The physiological profiles of micro-organisms inhabiting the contaminated and the colntrol soils are distinctly different.

DNA Contents in Soil Contaminated with Heavy Metals

Abstract: The study was performed to show how industrial activity affected soil quality in terms of soil DNA quality and quantity as well as soil characteristics. Soil material originated from an urban area of the Silesia Region (SW Poland). The soil characteristics were estimated: texture, moisture, pH, redox potential (Eh), and total carbon content (TOC), followed by determination of selected heavy metals (Pb, Cd, Zn, Cr, Fe, Cu). The last step was the isolation of soil DNA, its concentration and identification of microorganisms. The results showed that although the studied soil was heavily contaminated with heavy metals, there were still some metal-resistant microorganisms able to sustain soil activity. Moreover, these organisms are not present in the NCBI database, which encourages further studies aimed at identification of new organisms that may be useful in research of metal resistance as well as soil reclamation and remediation. Keywords: Heavy metal, metal resistant bacteria, soil, t-DNA.