Crude oil pollution of soil is a serious environmental issue, and bioremediation using plants and microorganisms is a natural and sustainable method for its restoration. Pot incubation of a two-factor randomized block (plants with two levels, and crude oil with three levels) was designed to investigate the rhizosphere bacterial community of Suaeda salsa (L.) Pall. Crude oil contamination of soil was studied at different levels: 2 g/kg (low), 4 g/kg (medium), and 6 g/kg (high) levels. In this study, the physicochemical properties of the collected rhizosphere soil were analyzed. Moreover, the soil bacteria were further identified using the 16S rRNA gene. The effects of S. salsa and crude oil and their interaction on the physiochemical properties of the soil and crude oil degradation were found to be significant. Crude oil significantly influenced the diversity and evenness of bacteria, while the effects of S. salsa and interaction with crude oil were not significant. Proteobacteria were found to be dominant at the phylum level. Meanwhile, at the genera level, Saccharibacteria and Alcanivorax increased significantly in the low and medium contamination treatment groups with S. salsa, whereas Saccharibacteria and Desulfuromonas were prevalent in the high contamination treatment group. High crude oil contamination led to a significant decrease in the bacterial diversity in soil, while the effects of S. salsa and its interaction were not significant. Despite the highest abundance of crude oil degradation bacteria, S. salsa reduced crude oil degradation bacteria and increased bacteria related to sulfur, phosphorus, and nitrogen cycling in the low and high contamination group, whereas the opposite effect was observed for the medium contamination treatment group. The abundance of most crude oil degradation bacteria is negatively correlated with crude oil content. Nitrogen cycling bacteria are sensitive to the total nitrogen, total phosphorus, ammonia nitrogen, and nitrate nitrogen, and pH of the soil. Sulfur cycling bacteria are sensitive to aromatic hydrocarbons, saturated hydrocarbons, and asphaltene in soil. This research is helpful for further studying the mechanism of synergistic degradation by S. salsa and bacteria.

Dry rivers could be effectively recovered by reclaimed water in North China, while river water quality would be an important issue. Therefore, it is important to understand the spatiotemporal variation and controlling factors of river water. Water samples were collected during March, May, July, September, and November in the year 2010, then 20 parameters were analyzed. The water environment was oxidizing and alkaline, which was beneficial for nitrification. Nitrate was the main nitrogen form. Depleted and enriched isotopes were found in reclaimed water and river water, respectively. Total nitrogen (TN) and total phosphorus (TP) of reclaimed water exceed the threshold of reclaimed water reuse standard and Class V in the surface water quality criteria. Most river water was at the severe eutrophication level. The sodium adsorption ratio indicated a medium harmful level for irrigation purpose. Significant spatial and temporal variation was explored by cluster analysis. Five months and nine stations were both classified into two distinct clusters. It was found that 6 parameters (chloride: Cl⁻, sulphate: SO₄²⁻, potassium: K⁺, sodium: Na⁺, magnesium: Mg²⁺, and total dissolved solids: TDS) had significant upward temporal variation, and 12 parameters (dissolved oxygen: DO, electric conductivity: EC, bicarbonate: HCO₃⁻, K⁺, Na⁺, Ca²⁺, TDS, nitrite-nitrogen: NO₂-N, nitrate nitrogen: NO₃-N, TN, TP, and chlorophyll a: Chl.a) and 4 parameters (Mg²⁺, ammonia nitrogen: NH₃-N, and the oxygen-18 and hydron-2 stable isotope: δ¹⁸O and δ²H) had a significant downward and upward spatial trend, respectively. The Gibbs plot showed that river water chemistry was mainly controlled by a water–rock interaction. The ionic relationship and principal component analysis showed that river water had undergone the dissolution of carbonate, calcite, and silicate minerals, cation exchange, a process of nitrification, photosynthesis of phytoplankton, and stable isotope enrichment. In addition, gypsum and salt rock have a potential dissolution process.

Reclaimed water is useful for replenishing dried up rivers in North China, although changes in water quality could be an issue. Therefore, it is essential to understand the spatio-temporal variation and the controlling factors of water quality. Samples of Yongding River water were collected seasonally, and 24 water quality parameters were analyzed in 2015. All waters were alkaline, and nitrate-nitrogen was the main form of nitrogen, while phosphorus was mostly below detection level. The water quality parameters varied in time and space. Cluster analysis showed a distinct difference between winter and the other seasons and between the natural river section and the section with reclaimed water. Based on the analysis of Gibbs plots, principal component analysis, and ionic relationships, the water chemistry was controlled by dissolution of rocks in natural river section, the quality of replenished water, the effects of dilution, and the reaction of aqueous chemistry in the reclaimed water section. The positive oxidation environment in most of the river water was conducive to the formation of nitrate-nitrogen by nitrification, and not conducive to denitrification.

Decreases in pan evaporation (E_pan) over the last decades have been reported in many regions of the world. In this study, changes of E_pan in the Zoige Plateau alpine wetland (hereinafter referred to as “Zoige wetland”) and its peripheral regions from 1969 to 2014 were investigated using the PenPan model based on the long-term meteorological data. The contribution of climate factors to E_pan change were quantified by using partial derivatives of the PenPan model. Results indicated that E_pan in Zoige wetland exhibited an obvious decreasing trend before 1989, but rapidly increased after 1990. The increase in E_pan in the Zoige wetland is more significant than that in its peripheral regions and the entire Tibetan Plateau, which contributed to the more significant warming in the Zoige wetland. The pan evaporation in Zoige wetland after 1990 could be mostly attributed to changes in the aerodynamic component, and the decreasing radiation and wind speed is the primary contributor to the decline of pan evaporation during 1969–1989, while increasing air temperature and vapor pressure deficit were the major contributors to the increase of pan evaporation after 1990.

The partitioning of available energy between sensible heat and latent heat is important for precise water resources planning and management in the context of global climate change. Land surface temperature (LST) is a key variable in energy balance process and remotely sensed LST is widely used for estimating surface heat fluxes at regional scale. However, the inequality between LST and aerodynamic surface temperature (T_aero) poses a great challenge for regional heat fluxes estimation in one-source energy balance models. To address this issue, we proposed a One-Source Model for Land (OSML) to estimate regional surface heat fluxes without requirements for empirical extra resistance, roughness parameterization and wind velocity. The proposed OSML employs both conceptual VFC/LST trapezoid model and the electrical analog formula of sensible heat flux (H) to analytically estimate the radiometric-convective resistance (r_ae) via a quartic equation. To evaluate the performance of OSML, the model was applied to the Soil Moisture-Atmosphere Coupling Experiment (SMACEX) in United States and the Multi-Scale Observation Experiment on Evapotranspiration (MUSOEXE) in China, using remotely sensed retrievals as auxiliary data sets at regional scale. Validated against tower-based surface fluxes observations, the root mean square deviation (RMSD) of H and latent heat flux (LE) from OSML are 34.5 W/m² and 46.5 W/m² at SMACEX site and 50.1 W/m² and 67.0 W/m² at MUSOEXE site. The performance of OSML is very comparable to other published studies. In addition, the proposed OSML model demonstrates similar skills of predicting surface heat fluxes in comparison to SEBS (Surface Energy Balance System). Since OSML does not require specification of aerodynamic surface characteristics, roughness parameterization and meteorological conditions with high spatial variation such as wind speed, this proposed method shows high potential for routinely acquisition of latent heat flux estimation over heterogeneous areas.