Changes in soil microbial communities as affected by intensive cattle husbandry

The present field study documents substantial changes in the soil microbial community (SMC) and organic matter (SOM) in an upland pasture soil resulting from 10 years of “cattle outdoor over-wintering practice”. Soils from a long-term investigated pasture area were compared under three different levels of cattle impact (SI – severe, MI – moderate, NI – no impact). Extended polar lipids analysis (PLA) confirmed a qualitatively new microbial community profile and a several-fold increase of the microbial biomass in the impacted soils (SI) compared to the control NI soil. The new SMC was derived from cattle intestine microorganisms, typical by increased content of archaeal phospholipid ether lipids and by new fatty acids indicative for bacterial and fungal fecal anaerobes. A quality of the SI-SOM, evaluated by the relative content of the pyrolytic fragments profile was more similar to the cattle excrements than to the MI and NI soils, and an organic carbon content of the SI soil was not more than three times higher in comparison to the control NI soil. The quality and quantity of the SOM as well as the SMC in both, the most impacted SI and the control NI soils, were stable in contrast to the moderately impacted MI soil. During the growing season, the MI soil lost 75% of the Corg and 65% of the soil microbial biomass that had accumulated during winter; its aromatic-rich-SOM showed transformation into SOM, enriched by N, P-organic derivates. This transformation was positively correlated to a significant recovery of the actinobacteria and reduction of anaerobic microorganisms during the vegetation season. Results in this study showed that the stability of the soil microbial changes due to the cattle outdoor over-wintering husbandry depended on the stability of the quantitative and qualitative changes of the SOM. © 2012 Published by Elsevier B.V

Komplexní geochemický výzkum interakcí a migrací organických a anorganických látek v horninovém prostředí:Mineralogicko-petrologická charakteristika referenčních vzorků

Projekt se zabývá výzkumem sorpčních charakteristik přírodních sorbentů. Základem je stanovení souboru vzorků tak, aby bylo možné interpertovat jejich chování v kolonách. Pro stanovení souboru vzorků z dvanácti lokalit byl proveden jejich makroskopický a mikroskopický popis, silikonové analýzy, RTG difrační analýzy celohorninových vzorků, RTG difrační analýzy vzorků frakce <2nm, IR analýzy vzorků frakce <2nm, chemické analýzy pomocí EDAXu. Na závěr proběhlo srovnání analýz jednotlivých lokalit. Jsou uvedeny podrobné výsledky

Anaerobic oxidation of methane in grassland soils used for cattle husbandry.

While the importance of anaerobic methane oxidation has been reported for marine ecosystems, the role of this process in soils is still questionable. Grasslands used as pastures for cattle-overwintering show an increase in anaerobic soil micro-sites caused by animal treading and excrement deposition. Therefore anaerobic potential methane oxidation activity of severely impacted soil from a cattle winter pasture was investigated in an incubation experiment under anaerobic conditions using 13C-labeled methane. We were able to detect a high microbial activity utilizing CH4 as nutrient source shown by the respiration of 13CO2. Measurements of possible terminal electron acceptors for anaerobic oxidation of methane were carried out. Soil sulfate concentrations were too low to explain the oxidation of the amount of methane added, but enough nitrate and iron(III) were detected. However, only nitrate was consumed during the experiment. 13C-PLFA analyses clearly showed the utilization of CH4 as nutrient source mainly by organisms harbouring 16:1&omega;7 PLFAs. These lipids were found in Gram-negative microorganisms and anaerobes. The fact that these lipids are also typical for type I methanotrophs, known as aerobic methane oxidizers, might indicate a link between aerobic and anaerobic methane oxidation

Komplexní geochemický výzkum interakcí a migrací organických a anorganických látek v horninovém prostředí:Sorpce těžkých kovů - kolonové experimenty

Byl zkoumán soubor nezpevněných sedimentů, který pokrýval zjištěný rozsah nejdůležitějších vlastností pro zkoumání sorpce těžkých kovů (zastoupení jílové frakce, obsah organických látek, obsah karbonátů). Ve vzorcích byla analyzována měď a kadmium. Jsou popsány kolonové experimenty a jejich výsledky

An organic semiconductor laser based on star-shaped truxene-core oligomers for refractive index sensing

The sensing capabilities of an all-organic semiconductor distributed feedback laser based on star-shaped truxene-core molecules are described. Two assays are presented as a proof-of-principle demonstration. In the first, concentration changes in the range of 5-60% (v/v) glycerol solution in water were measured with a bulk detection sensitivity of 21 nm per refractive index unit. Secondly, layer-by-layer adsorption of polyelectrolytes to the laser surface, up to a thickness of ≈45 nm, was measured. The experimental results from both assays are compared to, and shown to agree with, a theoretical model. Organic semiconductor lasers of this type have a number of attractions including ease of large-scale fabrication, incorporation into existing assay equipment and no rigid optical alignment constraints for excitation and collection of emission, which makes them well-suited to sensing applications. Therefore, it is expected that this technology will be useful in biosensing applications where label-free samples are investigated