Microbial metabolic strategies for overcoming low-oxygen in naturalized freshwater reservoirs surrounding the Athabasca Oil Sands: A proxy for End-Pit Lakes?

Bacterial community profile of the crude oil-contaminated saline soil in the Yellow River Delta Natural Reserve, China

Crude oil contamination greatly influence soil bacterial community. Proliferative microbes in the crude oil-contaminated soil are closely related to the living conditions. Oil wells in the Yellow River Delta Natural Reserve (YRDNR) region is an ideal site for investigating the bacterial community of crude oil-contaminated saline soil. In the present study, 18 soil samples were collected from the depths of 0-20 cm and 20-40 cm around the oil wells in the YRDNR. The bacterial community profile was analyzed through high-throughput sequencing to trace the oil-degrading aerobic and anaerobic bacteria. The results indicated that C₁₅-C₂₈ and C₂₉-C₃₈ were the main fractions of total petroleum hydrocarbon (TPH) in the sampled soil. These TPH fractions had a significant negative effect on bacterial biodiversity (Shannon, Simpson, and Chao1 indices), which led to the proliferation of hydrocarbon-degrading bacteria. A comprehensive analysis between the environmental factors and soil microbial community structure showed that Streptococcus, Bacillus, Sphingomonas, and Arthrobacter were the aerobic hydrocarbon-degrading bacteria; unidentified Rhodobacteraceae and Porticoccus were considered to be the possible facultative anaerobic bacteria with hydrocarbon biodegradation ability; Acidithiobacillus, SAR324 clade, and Nitrosarchaeum were predicted to be the anaerobic hydrocarbon-degrading bacteria in the sub-surface soil. Furthermore, large amount of carbon sources derived from TPH was found to cause depletion of bioavailable nitrogen in the soil. The bacteria associated with nitrogen transformation, such as Solirubrobacter, Candidatus Udaeobacter, Lysinibacillus, Bradyrhizobium, Sphingomonas, Mycobacterium, and Acidithiobacillus, were highly abundant; these bacteria may possess the ability to increase nitrogen availability in the crude oil-contaminated soil. The bacterial community functions were significantly different between the surface and the sub-surface soil, and the dissolved oxygen concentration in soil was considered to be potential influencing factor. Our results could provide useful information for the bioremediation of crude oil-contaminated saline soil.

Impact of sample collection on prokaryotic and eukaryotic diversity of niche environments of the oil-sand mining impacted Athabasca River

Microbial communities are an important aspect of overall riverine ecology; however, appreciation of the effects of anthropogenic activities on unique riverine microbial niches, and how the collection of these samples affects the observed diversity and community profile is lacking. We analyzed prokaryotic and eukaryotic communities from surface water, biofilm, suspended load niches along a gradient of oil sands-related contamination in the Athabasca River (Alberta, Canada), with suspended load or particle-associated communities collected either via Kenney Sampler or centrifugation manifold. At the level of phyla, different niche communities were highly similar to one another and across locations. However, there were significant differences in the abundance of specific genera amongst different niches and across sampling locations. A generalized linear model revealed that use of the Kenney Sampler resulted in more diverse bacterial and eukaryotic suspended load community than centrifugal collection, though "suspended load" communities collected by any means remained stably diverse across locations. Though there was influence of water quality parameters on community composition, all sampled sites support diverse bacterial and eukaryotic communities regardless of the degree of contamination, highlighting the need to look beyond ecological diversity as means of assessing ecological perturbations, and consider collecting samples from multiple niche environments.

Contaminated aquatic sediments

Aquatic sediments are contaminated by different anthropogenic activities and natural deposition. This review manuscript has discussed on published manuscript in 2019 based on monitoring and identification of contaminants, GIS application and isotopic evaluation for monitoring of pollutants, physicochemical and biochemical fate and transport of the pollutants as well as remediation and toxicity analysis so that environmental and ecological impacts due to pollution can be minimized.

The simultaneous detection of the squamous cell carcinoma antigen and cancer antigen 125 in the cervical cancer serum using nano-Ag polydopamine nanospheres in an SERS-based lateral flow immunoassay

The accurate analysis of tumor related biomarkers is extremely critical in the diagnosis of the early stage cervical cancer. Herein, we designed a novel and inexpensive surface-enhanced Raman scattering-based lateral flow assay (SERS-based LFA) strip with a single test line, which was applied for the rapid and sensitive quantitative simultaneous analysis of SCCA and CA125 in serum samples from patients with cervical cancer. In the presence of target antigens, the monoclonal antibody-coupled and Raman reporter-labeled nano-Ag polydopamine nanospheres (PDA@Ag-NPs) aggregated on the test line modified by the polyclonal antibody to form a double-antibody sandwich structure. The finite difference time domain simulation demonstrated that large number of “hot spots” was generated among the nanogaps of aggregated PDA@AgNPs, which resulted in a huge enhancement of the signal of the Raman reporters. Accordingly, the limit of detection was determined to be 7.156 pg mL⁻¹ for SCCA and 7.182 pg mL⁻¹ for CA125 in phosphate buffer and 8.093 pg mL⁻¹ for SCCA and 7.370 pg mL⁻¹ for CA125 in human serum, revealing high sensitivity of this SERS-based LFA strip. Significantly, the detection of SCCA and CA125 using the SERS-based LFA was observed to have high specificity and reproducibility, and the whole detection was completed within 20 min. Furthermore, the SERS-based LFA and enzyme-linked immunosorbent assay were also employed in serum samples obtained from patients with cervical cancer, cervical intraepithelial neoplasia and healthy subjects, and perfect agreement existed between both the methods. Thus, clinically, the developed SERS-based LFA strip has strong potential for the simultaneous detection of multiple cancer biomarkers in serum.

Based on SERS-based lateral flow immunoassay, nano-Ag polydopamine nanospheres was used for detecting squamous cell carcinoma antigen and cancer antigen 125 simultaneously in cervical cancer serum.

Tracking functional bacterial biomarkers in response to a gradient of contaminant exposure within a river continuum

Within all aquatic environments, aside from the physical dispersal of dissolved and/or particulate phase contaminants, alteration from both biological and chemical processes are shown to change the chemistry of the parent compounds. Often these alterations can lead to secondary influences because of cooperative microbial processes (i.e. coupled respiratory pathways and/or energy and biodegradation cycles), complicating our understanding of the biological impact that these mobile compounds impose on ecosystem health. The McMurray Formation (MF) (the formation constituting the minable bituminous oil sands) is a natural, ongoing source of hydrocarbon-bound sediments to river ecosystems in the region (via terrestrial and aquatic erosion), providing a natural "mesocosm" to track and characterize the effects of these compounds on regional aquatic primary productivity. Here we characterize the natural, in-situ microbial response to increasing hydrocarbon exposure along a river continuum in the downstream direction. Using the Steepbank River (STB), suspended and bed sediment samples were collected at 3 sites from upstream to downstream, as the water flows into and through the MF. Samples were then analyzed for the active, in-situ gene expression of the microbial communities. Results from both suspended and bed sediments show clear and significant shifts in the microbial metabolic processes within each respective compartment, in response to the elevated polycyclic aromatic compound (PAC) concentrations. Specific genes likely responsible for hydrocarbon breakdown (Alkane Monooxygenase, Benzoyl-CoA Reductase etc.) experience elevated expression levels, while certain energy metabolism genes (nitrogen, sulfur, methane) reveal fundamental shifts in their pathway specificity, indicating an adaptation response in their basic energy metabolism. Expression from suspended sediments reveal subtle yet delayed metabolic response further downstream compared to bed sediments, indicative of the erosion and transport dynamics within a lotic system. These results provide insight into the use of novel clusters of gene biomarkers to track the active, in-situ microbial response of both emerging and legacy contaminants. Such information will be important in determining the best management strategies for the monitoring and assessment of aquatic health in both natural and contaminated ecosystems.

Water Quality Responses during the Continuous Mixing Process and Informed Management of a Stratified Drinking Water Reservoir

Aeration and mixing have been proven as effective in situ water quality improvement methods, particularly for deep drinking water reservoirs. While there is some research on the mechanism of water quality improvement during artificial mixing, the changes to water quality and the microbial community during the subsequent continuous mixing process is little understood. In this study, we investigate the mechanism of water quality improvement during the continuous mixing process in a drinking water reservoir. During this period, we found a reduction in total nitrogen (TN), total phosphorus (TP), ammonium-nitrogen (NH4-N), iron (Fe), manganese (Mn), and total organic carbon (TOC) of 12.5%–30.8%. We also measured reductions of 8.6% and 6.2% in TN and organic carbon (OC), respectively, in surface sediment. Microbial metabolic activity, abundance, and carbon source utilization were also improved. Redundancy analysis indicated that temperature and dissolved oxygen (DO) were key factors affecting changes in the microbial community. With intervention, the water temperature during continuous mixing was 15 °C, and the mixing temperature in the reservoir increased by 5 °C compared with natural mixing. Our research shows that integrating and optimizing the artificial and continuous mixing processes influences energy savings. This research provides a theoretical basis for further advancing treatment optimizations for a drinking water supply.