To study the spatial distributions and seasonal differences of concentrations, source identification, and phase partitioning of polycyclic aromatic hydrocarbons (PAHs) in surface water, intensive sampling was carried out along the marginal seas of China in four seasons. In the northern South China Sea (SCS), the highest PAH levels occurred in the summer (July to August) and autumn (October to November). In the East China Sea (ECS) and the Yellow Sea, the highest occurred in the summer (August) and winter (December). In all areas, the lowest PAH levels were found in the spring (May to June). The estimated mass inventory of PAHs in the surface water (0-5 m) of the northern SCS and ECS accounted for less than 8% of PAHs outflow into the offshore environment. That showed the consistent seasonal variation with PAHs levels. Land- and ocean-based emissions, surface runoff, and the open seawater dilution were the most important environmental factors influencing the seasonal heterogeneity and the spatial distributions of PAH in the surface water. The decline of observed organic carbon normalized partition coefficients in the four seasons was probably affected by the presence of submicrometer-sized soot particles accompanying the PAH outflow from China.

Summary To evaluate the benefits of application of biochar to coastal saline soil for climate change mitigation, the effects on soil organic carbon (SOC), greenhouse gases (GHGs) and crop yields were investigated. Biochar was applied at 16 t ha−1 to study its effects on crop growth (Experiment I). The effects of biochar (0, 3.2, 16 and 32 t ha−1) and corn stalk (7.8 t ha−1) on SOC and GHGs were studied using 13C stable isotope technology and a static chamber method, respectively (Experiment II). Biochar increased grain mass per plant of the wheat by 27.7% and increased SOC without influencing non‐biochar SOC. On average, 92.3% of the biochar carbon and 16.8% of corn‐stalk carbon were sequestered into the soil within 1 year. The cumulative emissions of CO2, CH4 and N2O were not affected significantly by biochar but cornstalk application increased N2O emissions by 17.5%. The global warming mitigation potential of the biochar treatments (−3.84 to −3.17 t CO2‐eq. ha−1 t−1 C) was greater than that of the corn stalk treatment (−0.11 t CO2‐eq ha−1 t−1 C). These results suggest that biochar application improves saline soil productivity and soil carbon sequestration without increasing GHG emissions.

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A Na 2 MnPO 4 F/C nanocomposite material is successfully synthesized via spray drying, followed by a hightemperature sintering method. It is shown that the highly phase-pure Na 2 MnPO 4 F with symmetry of the P2 1 /n space group is uniformly embedded in the carbon networks, which play a key role in building up a highly efficient, electron-flow channel and elevating the electronic conductivity of the nanocomposites.The electrochemical measurements show that the initial discharge capacity of Na 2 MnPO 4 F reaches up to 140 and 178 mA h g À1 at 30 C and 55 C, respectively. Furthermore, the capacity still maintains 135 mA h g À1 after 20 cycles at 55 C. The Na + diffusion coefficient in Na 2 MnPO 4 F is calculated at about 10 À17 cm 2 s À1 by the GITT method. The impressive cycling performance of the material is ascribed to the good structural reversibility and stability of Na 2 MnPO 4 F, which are confirmed by the ex situ XRD measurements during the first cycle and after 30 cycles.

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Plants are associated with hundreds of thousands of microbes that are present outside on the surfaces or colonizing inside plant organs, such as leaves and roots. Plant-associated microbiota plays a vital role in regulating various biological processes and affects a wide range of traits involved in plant growth and development, as well as plant responses to adverse environmental conditions. An increasing number of studies have illustrated the important role of microbiota in crop plant growth and environmental stress resistance, which overall assists agricultural sustainability. Beneficial bacteria and fungi have been isolated and applied, which show potential applications in the improvement of agricultural technologies, as well as plant growth promotion and stress resistance, which all lead to enhanced crop yields. The symbioses of arbuscular mycorrhizal fungi, rhizobia and Frankia species with their host plants have been intensively studied to provide mechanistic insights into the mutual beneficial relationship of plant–microbe interactions. With the advances in second generation sequencing and omic technologies, a number of important mechanisms underlying plant–microbe interactions have been unraveled. However, the associations of microbes with their host plants are more complicated than expected, and many questions remain without proper answers. These include the influence of microbiota on the allelochemical effect caused by one plant upon another via the production of chemical compounds, or how the monoculture of crops influences their rhizosphere microbial community and diversity, which in turn affects the crop growth and responses to environmental stresses. In this review, first, we systematically illustrate the impacts of beneficial microbiota, particularly beneficial bacteria and fungi on crop plant growth and development and, then, discuss the correlations between the beneficial microbiota and their host plants. Finally, we provide some perspectives for future studies on plant–microbe interactions.

In this study, porous polypyrrole (PPy) film was synthesized by facile interfacial polymerization using ionic liquid as oxidant. The morphology of PPys changed from dense microspherical/nanospherical agglomerated structure to porous structure with the increasing concentration of the oxidant. The magnetic ionic liquid, 1-butyl-3-methylimidazolium tetrachloroferrate (Bmim[FeCl 4 ]), played a major role of oxidant when the concentration was lower than 0.075M. As the concentration increased to 0.075M, the p-p interactions between pyrrole cations and iminazole ring of Bmim[FeCl 4 ], as evidenced by Fourier transform infrared spectrometer results, may affect the packing of PPy chains and subsequently cause the formation of porous structure of PPys. Electrochemical performances showed that PPy with porous structure displayed the highest specific capacitance of 170 F/g at a current density of 2 A/g in 1M H 2 SO 4 solution and a good capacitive behavior, which has potential application as supercapacitor materials.

To investigate the characteristics of historicuse organochlorine pesticides (OCPs) in the marginal seawater of China, we examined the seasonal and spatial distributions of hexachlorobenzene (HCB), hexachlorocyclohexanes (HCHs), and dichlorodiphenyltrichloroethane (DDTs) in the northern South China Sea (NSCS, 18−23°N) and East China Sea (ECS, 26−32°N). Seasonally, in the NSCS, the significantly higher concentrations (p < 0.05) of HCB, HCHs, and DDTs were found in summer, autumn, and summer through autumn, respectively. In the ECS, the higher concentrations were found in summer through winter, autumn, and summer. Spatially, HCB concentrations were significantly higher in the NSCS than in the ECS during all seasons except winter. During all four seasons, concentrations of HCHs were significantly higher in the NSCS than in the ECS. In summer and autumn, concentrations of DDTs were significantly higher in the NSCS than in the ECS, while no significant differences were found in spring and winter. Generally, regional usage, river-influenced coastal plumes, phytoplankton abundances, and ocean currents played crucial roles in the input, transport, degradation, and dilution of OCPs. These dynamic factors along with the seasonally alternating monsoon directly influenced the seasonal and spatial characteristics of OCPs. Furthermore, the profiles and diagnostic ratios of HCHs and DDTs revealed highly weathered OCP residues, attributed to eroded soils carried by surface runoff and long-range oceanic and atmospheric transport.