Vadjama8606

A novel method based on relational analysis is presented for assessing the performance of conventional oil exploitation and its environmental implications, with a focus on the energy-water nexus. It considers the energy system as a metabolic network and integrates various factors relevant for technical, economic and environmental processes, thus avoiding some of the simplifications inherent in conventional approaches to the assessment of primary resource quality, such as economic cost-benefit analysis (CBA) and the energy return on investment (EROI). Relational analysis distinguishes between functional (notional) and structural (tangible) elements in the metabolic network, which allows a simultaneous characterization and geo-localization of the exploitation process across different scales and dimensions of analysis. Key aspects of the approach are illustrated with data from the Ecuadorian oil sector spanning the period 1972-2018. It is shown that by establishing a relation among the characteristics of the exploited oil fields (oil typology, age of field) and those of the exploitation process (requirement of energy carriers, labor, freshwater and power capacity and generation of greenhouse gases and oil-produced water), changes in the performance and environmental implications of the oil extraction system can be characterized at different points in space and time.Clostridium tyrobutyricum is a promising microbial cell factory to produce biofuels. In this study, an uptake hydrogenase (hyd2293) from Ethanoligenens harbinense was overexpressed in C. tyrobutyricum and significantly affected the redox reactions and metabolic profiles. Compared to the parental strain (Ct-WT), the mutant strain Ct-Hyd2293 produced ~34% less butyrate, ~148% more acetate, and ~11% less hydrogen, accompanied by the emerging genesis of butanol. Comparative transcriptome analysis revealed that 666 genes were significantly differentially expressed after the overexpression of hyd2293, including 82 up-regulated genes and 584 down-regulated genes. The up-regulated genes were mainly involved in carbohydrate and energy metabolisms while the down-regulated genes were distributed in nearly all pathways. Genes involved in glucose transportation, glycolysis, different fermentation pathways and hydrogen metabolism were studied and the gene expression changes showed the mechanism of the metabolic flux redistribution in Ct-Hyd2293. The overexpression of uptake hydrogenase redirected electrons from hydrogen and butyrate to butanol. The key enzymes participating in the energy conservation and sporulation were also identified and their transcription levels were generally reduced. This study demonstrated the transcriptomic responses of C. tyrobutyricum to the expression of a heterologous uptake hydrogenase, which provided a better understanding of the metabolic characteristics of C. tyrobutyricum and demonstrated the potential role of redox manipulation in metabolic engineering for biofuel productions.Modelling of partial nitrification process is affected by several factors such as selection of true substrates, FA and FNA inhibition, and pH effect on growth rate. Among these factors, the selection of true substrates is very critical as it affects the structure of the model. In the present work, a new model adopting free ammonia (FA) and free nitrous acids (FNA) as the true substrate for ammonia oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB) was proposed. Then the proposed model was compared with two reported models which adopted ammonium and nitrite, and FA and nitrite as the true substrate for AOB and NOB, respectively. The three mathematical models were compared in terms of predicted minimum dissolved oxygen (DO) in response to varied solids retention time (SRT) (10-30 d), pH (7-8.5), and temperature (10-35 °C). The input kinetic values were justified and updated based on statistical analysis of literature data. Adopting FA as the true substrate increased the minimum DO for AOB. Further, experimental data from different literature studies were taken for model simulation and comparison. Inconsistency was observed between the model prediction and literature data for all three models. The model that adopted ammonium and nitrite as the true substrate for AOB and NOB had better consistency with literature data than other two models. The affecting factors for the model prediction was classified into three levels and discussed in detail. Future work was proposed. The results of this study provide valuable information for the design and modelling of partial nitrification process.The coexistence of denitrification and bacterial sulfate reduction (BSR) processes is commonly observed in natural water systems. However, its formation mechanism remains unclear at a basin scale due to the difficulty of precise identification of these processes. To address this issue, we investigated the spatial-temporal variations in water chemistry and isotopic compositions (e.g., δ13CDIC, δ15NNO3, δ18ONO3, δ34SSO4, and δ18OSO4) in cascade reservoirs (artificial dam lakes) of the Jialing River, SW China in 2016. The results showed that the denitrification and BSR processes coexisted in the studied reservoirs, which was supported by the positive correlation between δ15NNO3 and δ18ONO3 and between δ34SSO4 and δ18OSO4, and by the decreasing concentrations of NO3- and SO42-. Moreover, covariation of Δ13CDIC, Δ15NNO3, and Δ34SSO4 indicated the dominance of heterotrophic denitrification (HD) in the reservoir waters along with the occurrence of bacterial sulfide oxidation (BSO). In addition to SO42- and NO3-, the coexistence of HD and BSR processes were also controlled by the dissolved organic carbon (DOC) in winter and dissolved oxygen (DO) contents in other seasons. Overall, the cumulative effect of cascade reservoirs caused δ15NNO3 and δ34SSO4 to display an upward trend from upstream to downstream in the Jialing River, while δ13CDIC showed an opposite downward trend, which implying that cascade reservoirs may be in favor of the coexistence of the HD and BSR processes. This study therefore concludes that the multi-isotope approach could be a useful technique to ascertain the coexistence mechanism of HD and BSR processes in reservoir water systems.Floral nectar harbors microbial communities which have significant impacts on its chemistry, volatiles, nutritional contents, and attractiveness for pollinators. Yet, fundamental knowledge regarding the structure and composition of nectar-associated microbiomes remains largely unknown. Especially elusive are the environmental factors and spatial effects that shape nectar-inhabiting microbial communities. The aim of this study was to explore and analyze the role of geographical and environmental factors affecting the composition and global distribution of floral nectar microbiota. learn more We explored and compared the structure of bacterial communities inhabiting the floral nectar of the widely spread and invasive tobacco tree (Nicotiana glauca) in six continents South and North America, Australia, Europe, Africa, and Asia, using 16S rRNA gene sequencing. Environmental abiotic data for each sampled plant was obtained from the Worldclim database and applied for inferring the effects of environmental conditions on bacterdistance and local environmental abiotic conditions affect and shape the composition and diversity of nectar inhabiting bacterial communities.Composted livestock manures, in both solid and liquid form, are used as fertilizers in cropland. However, excess solid and liquid manures in agricultural watersheds are considered as nonpoint pollution sources because of their high nutrient and heavy metal contents of, as well as their antibiotic contents, especially veterinary antibiotics (VAs). In this study, 21 VAs under nine classes (i.e., cephems, ionophores, lincosamides, penicillins, pleuromutilins, quinolones, streptogramins, sulfonamides, and tetracyclines) found in agricultural watersheds were simultaneously analyzed via UHPLC-q-orbitrap high-resolution mass spectrometry using an on-line solid-phase extraction system. The residues of VAs in the surface water of two intensive livestock rearing watersheds (Cheongmi and Gwangcheon streams) in Korea were successfully quantified, and the values were found to range from 1.84 ± 0.42 ng L-1 to 835.6 ± 31.9 ng L-1. Time lags of 2-3 months were observed between the periods of liquid manure application and the periods with the maximum concentrations of VAs. In both watersheds, samples from points close to areas with extensive application of liquid manure exhibited high concentrations of most of the 21 VAs. Between the watersheds, the one with heavier application of liquid manure showed higher concentrations of the target VAs. To the best of our knowledge, this study represents the first attempt at evaluating the correlation between liquid manure application and environmental occurrence of VAs in surface water. The findings reveal that liquid manure application plays an important role in introducing VAs into aquatic environments.Contaminant loads to rivers of the Canadian oil sands region are linked to industrial and natural sources. To date, biomonitoring studies have been unable to unequivocally assess potential environmental impacts associated with this development. As part of the Joint Alberta-Canada Oil Sands Monitoring initiative, we aimed to assess cumulative effects of anthropogenic activities and exposure to natural bitumen geology on benthic macroinvertebrate assemblages in the lower Athabasca River. We examined associations among macroinvertebrates and environmental correlates, such as nutrients, ions, metals, polycyclic aromatic compounds, and total suspended solids. The study design included sites within and outside the mineable bitumen deposits, within and outside of the active mining and extraction area, and above and below municipal sewage effluents. We predicted observing a negative association between ecological condition of the river and exposure to natural bitumen and oil sands activity. However, contaminant conce release of treated oil sands process water. Focused investigation-of-cause studies are required to better assess the consequences of cumulative interactions and ecological effects of nutrients and contaminant exposure in this system.Under global climate change and pressure from human activities, water scarcity is becoming a major concern in the quest for regional sustainable development in the Yellow River Basin (YRB). This study integrates scenarios of climate change and human activities under the Representative Concentration Pathway (RCP4.5 and RCP8.5) with a watershed-scale hydrological model, and uses the Water Use-to-Availability Ratio (WUAR) to study future water scarcity over six sub-catchments in the YRB. It further investigates the relationship between the future water scarcity and hydroclimatic and anthropogenic drivers. The results suggest that the average WUAR under both RCP4.5 and RCP8.5 will likely exceed the water scarcity threshold (WUAR >20%) and will reach up to 39.9 and 44.7%, respectively. The average WUAR for the upstream and downstream sub-catchments will likely range from 23.8 to 51.6% under RCP4.5 and from 25.5% to 73.8% under RCP8.5, indicating moderate to severe and moderate to extreme water scarcity, respectively.