Microbial community structure is affected by both natural processes and human activities. In coastal area, anthropegenetic activity can usually lead to the discharge of the effluent from wastewater treatment plant (WWTP) to sea, and thus the water quality chronically turns worse and marine ecosystem becomes unhealthy. Microorganisms play key roles in pollutants degradation and ecological restoration; however, there are few studies about how the WWTP effluent disposal influences coastal microbial communities. In this study, sediment samples were collected from two WWTP effluent-receiving areas (abbreviated as JX and SY) in Hangzhou Bay. First, based on the high-throughput sequencing of 16S rRNA gene, microbial community structure was analyzed. Secondly, several statistical analyses were conducted to reveal the microbial community characteristics in response to the effluent disposal. Using PCoA, the significant difference of in microbial community structure was determined between JX and SY; using RDA, water COD and temperature, and sediment available phosphate and ammonia nitrogen were identified as the key environmental factors for the community difference; using LDA effect size analysis, the most distinctive microbes were found and their correlations with environmental factors were investigated; and according to detrended beta-nearest-taxon-index, the sediment microbial communities were found to follow “niche theory”. An interesting and important finding was that in SY that received more and toxic COD, many distinctive microbes were related to the groups that were capable of degrading toxic organic pollutants. This study provides a clear illustration of eco-environmental deterioration under the long-term human pressure from the view of microbial ecology.
Pores with sizes ranging from nanometers to micrometers are widely distributed in shale gas and shale oil formations. These pores are the sites for hydrocarbon accumulation and provide the flow paths for hydrocarbons during production. The Middle Bakken member is the main production zone of the Bakken Formation in North Dakota. In order to reveal the pore structures of the Middle Bakken, we employed field emission scanning electron microscopy (FE-SEM). After segmentation of the SEM images, we calculated the surface area and shape of the pores using image analysis and then quantified the complexity and heterogeneity of the pore structures by applying both fractal and multifractal analyses. Finally, we employed the fractal permeability model to estimate the permeability of the samples. The results showed that different pore types, such as interparticle and intraparticle pores exist in the Middle Bakken samples. Even under the same scale of the same sample, the pore parameters could be different. Sample 2 has the largest average porosity, followed by Sample 1 and Sample 3. The mean pore size of these samples is less than 31 nm indicating that the pores in Middle Bakken samples are very small. The pore structures in the Middle Bakken exhibited fractal and multifractal behavior. The fractal dimension from the entire size range of pores is the largest compared with the fractal dimension of the subdivided groups. The pore size distribution in Sample 2 is the most heterogeneous.
During the period 2012-2015, photolysis frequencies were measured at the Peking University site (PKUERS), a site representative of Beijing. We present a study of the effects of aerosols on two key photolysis frequencies, j((OD)-D-1) and j(NO2). Both j((OD)-D-1) and j(NO2) display significant dependence on aerosol optical depth (AOD; 380 nm) with a non-linear negative correlation. With the increase in AOD, the slopes of photolysis frequencies vs. AOD decrease, which indicates that the capacity of aerosols to reduce the actinic flux decreases with AOD. The absolute values of slopes are equal to 4.2-6.9x10(-6) and 3.4x10(-3) s(-1) per AOD unit for j((OD)-D-1) and j(NO2) respectively at a solar zenith angle (SZA) of 60 degrees and AOD smaller than 0.7, both of which are larger than those observed in a similar, previous study in the Mediterranean. This indicates that the aerosols in Beijing have a stronger extinction effect on actinic flux than absorptive dust aerosols in the Mediterranean. Since the photolysis frequencies strongly depended on the AOD and the SZA, we established a parametric equation to quantitatively evaluate the effect of aerosols on photolysis frequencies in Beijing. According to the parametric equation, aerosols lead to a decrease in seasonal mean j(NO2) by 24% and 30% for summer and winter, respectively, and a corresponding decrease in seasonal mean j((OD)-D-1) by 27% and 33 %, respectively, compared to an aerosol-free atmosphere (AOD = 0). Based on an observation campaign in August 2012, we used a photochemical box model to simulate the ozone production rate (P(O-3)). The simulation results shows that the monthly mean daytime net ozone production rate is reduced by up to 25% due to the light extinction of aerosols. Through further in-depth analysis, it was found that particulate matter concentra-tions maintain a high level under the condition of high concentrations of ozone precursors (volatile organic compounds, VOCs, and NOx), which inhibits the production of ozone to a large extent. This phenomenon implies a negative feedback mechanism in the atmospheric environment of Beijing.
Tourism’s impacts on ethnic cultures have received much attention, but few studies have been done on its impacts on nomadic people, especially for Kazakh nomads in China. Many Kazakh households are experiencing a transition from pastoralism to tourism, with yurt tourism being the popular Kazakh tourism products. This study takes Narat in China as a case to understand the impact of yurt tourism on the gendered labor division of Kazakh families, and the status of Kazakh women. Observations and semi-structured interviews were adopted. We find that the division of labor in yurt tourism is an extension of traditional nomad labor division and that the traditional gender statuses have been reinforced. Women are required to not only work but also face additional social pressure since they are considered to be going against customary rules when greeting tourists. Despite this, women’s self-confidence, business skills, and income have improved since the development of tourism. We argue that the form of tourism product, ideology of gender roles, and position of ethnic families in the tourism market account for this change. Diverse results of tourism impacts on the gender relationships of ethnic communities can be derived from the interactions of these three factors.
BACKGROUND: Exploring the associations of air pollution and weather variables with blood leukocyte distribution is critical to understand the impacts of environmental exposures on the human immune system. OBJECTIVES: As previous analyses have been mainly based on data from cell counters, which might not be feasible in epidemiologic studies including large populations of long-stored blood samples, we aimed to expand the understanding of this topic by employing the leukocyte distribution estimated by DNA methylation profiles. METHODS: We measured DNA methylation profiles in blood samples using Illumina HumanMethylation450 BeadChip from 1519 visits of 774 Caucasian males participating in the Normative Aging Study. Leukocyte distribution was estimated using Houseman's and Horvath's algorithms. Data on air pollution exposure, temperature, and relative humidity within 28days before each blood draw was obtained. RESULTS: After fully adjusting for potential covariates, PM2.5, black carbon, particle number, carbon monoxide, nitrogen dioxide, sulfur dioxide, temperature, and relative humidity were associated with the proportions of at least one subtype of leukocytes. Particularly, an interquartile range-higher 28-day average exposure of PM2.5 was associated with 0.147-, 0.054- and 0.101-unit lower proportions (z-scored) of plasma cells, naive CD8+ T cells, and natural killers, respectively, and 0.059- and 0.161-unit higher proportions (z-scored) of naive CD4+ T cells and CD8+ T cells, respectively. CONCLUSIONS: Our study suggests that short-term air pollution exposure, temperature, and relative humidity are associated with leukocyte distribution. Our study further provides a successful attempt to use epigenetic patterns to assess the influences of environmental exposures on human immune profiles.
Methanesulfonate, an important oxidation product of dimethyl sulfide, is abundant in marine aerosol particles. However, its impact on the cloud condensation nucleation (CCN) activity of marine aerosol is yet to be elucidated, largely because the CCN activity of methanesulfonate has been seldom investigated. In this work, we measured the CCN activities of three common methanesulfonates, and the single hygroscopicity parameters (κ) were determined to be 0.46 ± 0.02 for sodium methanesulfonate (NaMS), 0.37 ± 0.01 for calcium methanesulfonate, and 0.47 ± 0.02 for potassium methanesulfonate, respectively. In addition, we explored the effect of NaMS on the CCN activities of NaCl and synthetic sea salt. It was found that if presented with a mass ratio of 1:1, NaMS would significantly reduce the CCN activities of NaCl and sea salt, and the κ values of binary mixtures could be estimated using the simple mixing rule. Nevertheless, if only presented with a mass ratio of 1:10 (an environmentally relevant value), the effect of NaMS on the CCN activities of NaCl and sea salt was found to be small. Overall, we conclude that from our experimental data and its levels found in the troposphere, methanesulfonate may only have minor impacts on the CCN activity of marine aerosol.
Rice paddy fields pose a high risk of water pollutions for the surrounding waterbodies through surface runoff and subsurface fluxes. Compared to surface runoff, subsurface flux from rice paddy fields has received less attention and is still poorly quantified, mainly due to low-frequency measurements at field scale and limited modeling capability at regional scale. Here we proposed a simplified modeling approach to estimate the subsurface fluxes of water, nitrogen (N) and phosphorus (P) from rice paddy fields and examined their relative importance compared to surface runoff. This model was established based on the high-frequency field measurements over two rice growing seasons in central China and the extended datasets across the East Asia. Two-year site-based observations indicate the significance of subsurface fluxes of water (737–785 mm season−1), N (28.5–40.0 kg N ha−1) and P (0.7–4.3 kg P ha−1) compared to those of surface runoff (178–199 mm season−1, 4.5–12.9 kg N ha−1, 0.5–2.6 kg P ha−1). Our regional estimations in the East Asia reveal that subsurface fluxes from rice paddy fields were comparable with surface fluxes, primarily controlled by the magnitude of seasonal precipitation. Subsurface fluxes were the dominant pathway of nutrient losses in drier rice cropping areas, while surface runoff was the more important process in wetter areas. In the light of the regional differences, we suggest that a spatially flexible set of policies for mitigating nutrient losses from rice paddy fields would be beneficial for the future water-quality improvements in the surrounding waterbodies.
Current estimates of China’s ammonia (NH3) volatilization from paddy rice differ by more than twofold, mainly due to inappropriate application of chamber-based measurements and improper assumptions within process-based models. Here, we improved the Jayaweera-Mikkelsen (JM) model through multiplying the concentration of aqueous NH3 in ponded water by an activity coefficient that was determined based on high-frequency flux observations at Jingzhou station in Central China. We found that the improved JM model could reproduce the dynamics of observed NH3 flux (R2 = 0.83, n = 228, P < 0.001), while the original JM model without the consideration of activity of aqueous NH3 overstated NH3 flux by 54% during the periods of fertilization and pesticide application. The validity of the improved JM model was supported by a mass-balance-based indirect estimate at Jingzhou station and the independent flux observations from the other five stations across China. The NH3 volatilization losses that were further simulated by the improved JM model forced by actual wind speed were in general a half less than previous chamber-based estimates at six stations. Difference in wind speed between the inside and outside of the chamber and insufficient sampling frequency were identified as the primary and secondary causes for the overestimation in chamber-based estimations, respectively. Together, our findings suggest that an in-depth understanding of NH3 transfer process and its robust representation in models are critical for developing regional emission inventories and practical mitigation strategies of NH3.