Legacy and dispersant influence microbial community dynamics in cold seawater contaminated by crude oil water accommodated fractions

Impact of carbon-based conductive materials on performance and microbial community composition during anaerobic digestion of butanol-octanol wastewater

Butanol-octanol wastewater (BOW) from coal syngas conversion with hazardous and high salinity could hinder anaerobic digestion (AD). The carbon-based conductive materials (CCM) appear viable for enhancing the AD capability of BOW. Nevertheless, the potential mechanisms of different CCM types on AD of BOW remain unclear. The three different morphologies of CCM, powdered activated carbon (PAC), granular activated carbon (GAC), and carbon fiber cloth (CFC), were employed to improve methane conversion rate in AD of actual BOW. Results indicated that, compared to other carbon materials, more aromatic functional groups on the surface of GAC promoted electron transfer and notably increased degradation of 3-heptanone in BOW and methanogenic. Microbial community structure analysis showed Geobacter on GAC increased to 30.99 %, while Syntrophomonas and Methanosaeta in the sludge increased by 5.05 % and 7.7 %, respectively. The methane conversion rate of BOW was increased by promoting direct interspecies electron transfer (DIET) through GAC.

Functional redundancy in response to runoff input upholds microbial community in hydrocarbon-contaminated land-sea continuum

An experimental approach mimicking the land-sea continuum in microcosms was developed in order to determine the effect of the terrigenous inputs by soil runoff on the microbial functional potential in hydrocarbon (HC) contaminated marine coastal sediment. We hypothesized that the coalescent event increases the functional potential of microbial communities in marine coastal sediments, influencing the fate of HC in marine coastal ecosystems. The microbial functional potential including the HC degradation ability was assessed by DNA-array to compare the sediment receiving or not terrigenous inputs. The removal of HC and the functional gene richness in sediment was unchanged with the terrigenous inputs. However, the gene variants (GVs) composition was modified indicating functional redundancy. In addition, functional indicators including GVs related to sulfite reduction, denitrification and polyaromatic degradation were identified in higher proportion in sediment receiving terrigenous inputs. The terrigenous inputs modified the functional co-occurrence networks, showing a reorganization of the GVs associations with an increase of the network complexity. Different keystone GVs ensuring similar functions were identified in networks with or without terrigenous inputs, further confirming functional redundancy. We argue that functional redundancy maintains the structure of microbial community in hydrocarbon-contaminated land-sea continuum mixing zone. Our results provide helpful functional information for the monitoring and management of coastal environment affected by human land-based activities.

Microbial community assembly responses to polycyclic aromatic hydrocarbon contamination across water and sediment habitats in the Pearl River Estuary

Along with rapid urbanization and intensive human activities, polycyclic aromatic hydrocarbon (PAH) pollution in the Pearl River Estuary (PRE) and its effects on the microbial community have attracted extensive attention. However, the potential and mechanism of microbial degradation of PAHs across water and sediment habitats remain obscure. Herein, the estuarine microbial community structure, function, assembly process and co-occurrence patterns impacted by PAHs were comprehensively analyzed using environmental DNA-based approaches. The contamination and distribution of PAHs were jointly affected by anthropogenic and natural factors. Some of the keystone taxa were identified as PAH-degrading bacteria (i.e., genera Defluviimonas, Mycobacterium, families 67-14, Rhodobacteraceae, Microbacteriaceae and order Gaiellales in water) or biomarkers (i.e., Gaiellales in sediment) that were significantly correlated with PAH levels. The proportion of deterministic process in the high PAH-polluted water (76%) was much higher than that in the low pollution area (7%), confirming the significant effect of PAHs on the microbial community assembly. In sediment, the communities with high phylogenetic diversity demonstrated a great extent of niche differentiation, exhibited a stronger response to environmental variables and were strongly influenced by deterministic processes (40%). Overall, deterministic and stochastic processes are closely related to the distribution and mass transfer of pollutants, and substantially affect the biological aggregation and interspecies interaction within communities in the habitats.

Microbial indicators along a metallic contamination gradient in tropical coastal sediments

The structure and diversity of microbial community inhabiting coastal sediments reflect the exposition to contaminants. Aiming to assess the changes in the microbiota from Sepetiba Bay (SB, Brazil) sediments, correlations between the 16S rRNA gene data (V4-V5 region), metal contamination factors (CF), and the ecological risk classification provided by the Quality Ratio (QR) index were considered. The results show that microbial diversity differs significantly between the less (SB external sector) and the most (SB internal sector) polluted sectors. Also, differences in the microbial community structure regarding the ecological risk classifications validated the QR index as a reliable tool to report the SB chronic contamination. Microbial indicator genera resistant to metals (Desulfatiglans, SEEP-SRB1, Spirochaeta 2, among others) presented mainly anaerobic metabolisms. These genera are related to the sulfate reducing and methanogenic metabolisms probably participating in the natural attenuation processes but also associated with greenhouse gas emissions. In contrast, microbial indicator genera sensitive to metals (Rubripirellula, Blastopirellula, Aquibacter, among others) presented mainly aerobic metabolisms. It is suggested that future works should investigate the metabolic functions to evaluate the influence of metallic contaminants on microbial community inhabiting SB sediment.

The Shaping of Daqing: Borderless Interactions between Oil and Urban Areas

Since the development of the oil industry in the 1860s, petroleum products became increasingly important in economies and shaped the urban form. The impact of oil exploration, exploitation, and transformation led to the creation of districts and cities entirely dedicated to the oil industry. This dynamic relationship between economic activity and urbanization was presented in the shaping of cities and their borders. Although important, the notion of borders and its consequences on the uses of land as well as on the life of inhabitants are often ignored. This paper first conceptualizes the term borders in understanding the interlinkages between oil and other areas closely related, either geographically or for the functioning of the oil industry; it then illustrates the intertwined borders of all these spaces from the contemporary example of the city of Daqing, in Northeast China. The paper answers the question of how past borders designed during the development of Daqing in the 1960s are impacting future planning strategies and the health of local inhabitants? By mapping the current land-use of the city, this paper elaborates on the need to consider borders beyond two-dimensional perspectives by revealing how spatial planning practices in oil-dependent cities can be an environmental issue today and in the future. The objective is to demonstrate the influence of past planning decisions linked to industrial activities on contemporary urban spaces.