RESUMEN
The studies of cyanobacterial blooms resulting from eutrophication or climate change and investigation of changes in the cyanobacterial community in freshwater environments are critical for the management of drinking water. Therefore, we investigated the cyanobacterial communities at 6 sites along the Nakdong River in South Korea from May 2012 to October 2012 by using high-throughput sequencing techniques and studied their relationship with various geochemical factors at sampling sites. Diverse genera (total of 175 genera) were detected within the cyanobacteria, and changes in their compositions were analyzed. The genus Prochlorococcus predominated in the May samples, especially in those obtained from the upstream part of the river, whereas the relative abundance of Microcystis and Anabaena increased with increase in water temperature. The relationship between the cyanobacterial community and environmental factors was analyzed by canonical correlation analysis, and the correlation between harmful cyanobacteria and chemical factors was analyzed by nonmetric multidimensional scaling ordination. Various environmental factors such as dissolved oxygen, pH, electric conductivity, temperature were found to affect the cyanobacterial communities in the river. The results of this study could help in the management of freshwater environments and in maintenance of drinking water quality.
Asunto(s)
Cianobacterias/aislamiento & purificación , Ríos/microbiología , Anabaena/aislamiento & purificación , Clorofila/análisis , Clorofila A , Cianobacterias/genética , Conductividad Eléctrica , Monitoreo del Ambiente , Concentración de Iones de Hidrógeno , Microcistinas/análisis , Microcystis/aislamiento & purificación , ARN Ribosómico 16S , República de Corea , Ríos/química , Microbiología del AguaRESUMEN
Due to the increasing demand for phytoremediation, many transgenic poplars have been developed to enhance the bioremediation of heavy metals. However, structural changes to indigenous fungal communities by genetically modified organisms (GMO) presents a major ecological issue, due to the important role of fungi for plant growth in natural environments. To evaluate the effect of GM plant use on environmental fungal soil communities, extensive sequencing-based community analysis was conducted, while controlling the influence of plant clonality, plant age, soil condition, and harvesting season. The rhizosphere soils of GM and wild type (WT) poplars at a range of growth stages were sampled together with unplanted, contaminated soil, and the fungal community structures were investigated by pyrosequencing the D1/D2 region of the 28S rRNA gene. The results show that the overall structure of the rhizosphere fungal community was not significantly influenced by GM poplars. However, the presence of GM specific taxa, and faster rate of community change during poplar growth, appeared to be characteristic of the GM plant-induced effects on soil-born fungal communities. The results of this study provide additional information about the potential effects of GM poplar trees aged 1.5-3 years, on the soil fungal community.
Asunto(s)
Hongos , Metales/metabolismo , Populus/metabolismo , Populus/microbiología , Biodegradación Ambiental , ADN de Hongos , Ecosistema , Hongos/clasificación , Hongos/genética , Filogenia , Plantas Modificadas Genéticamente , Populus/genética , Microbiología del SueloRESUMEN
The removal of ammonium from coagulated tannery wastewaters was investigated by an electrochemical method using Ti/IrO2 as an anode. Operating variables including the current density, pH and chloride concentration were considered in order to determine their effect on the ammonium removal efficiency. A maximum ammonium removal rate of 78.9% was achieved after 30 min of electrochemical treatment with 4 A dm(-2) of current density. During the electrolysis, it had been observed that the ammonium removal was accompanied with an elimination of the organics. Generation of hydroxyl radical was identified during the experiment with hydroxyl radical probe compound of pCBA. Chloride ion worked as the scavenger of hydroxyl radical. Role of free chlorine was the main oxidant for the elimination of ammonium and organic substances. As a result, the biodegradability of tannery wastewater increased after electrochemical treatment. The energy consumed per 1 kg of ammonium removal was 26.6 kWh for initial NH4-N concentration of 870 mg L(-1).