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The aboveground ant nests are admitted as hot spots for CO 2 emissions which increase heterogeneity of soil carbon (C) flux in forest ecosystems. However, little is known about effects of underground-nesting ant species on C emissions in tropical forests, where the ants have high diversity and abundance. In this study, we chose three underground-nesting ant species with different feeding-behaviors ( Pheidole capellini - predominantly honeydew harvester, Odontoponera transversa - predominantly predator, and Pheidologeton affinis - scavenger) to explore their impacts on soil CO 2 emission in Xishuangbanna tropical forest, China. We observed a pronounced effect of ants on CO 2 emission, and the effect varied with ant species. The mean CO 2 emissions were 2.4 times higher in P . capellini nests than in the reference soils, while those in nests of O . transversa and P . affinis were 2.0 and 1.6 folds, respectively. The contribution of total CO 2 flux from nests of three ant species comprised 0.01–0.54% of total annual CO 2 efflux from the forest floor. The CO 2 emission in ant nests and reference soils increased exponentially with soil temperature and water. Soil water was considerably increased by ant nesting, which explained nearly 93–97% of CO 2 emissions. However, soil temperature was not significantly different between nests and reference soils, and it only explained about 54–70% of CO 2 emission. Ant species differed in increase of soil microbial biomass carbon, total organic carbon, readily oxidizable organic carbon, soil bulk density and pH, which also contributed to a diverse effect on soil CO 2 emission. We suggest that the different effects of ant species on C emission may be closely associated with diversity of ant population size, feeding-behaviors and nesting modification on soil microbial biomass carbon, and physicochemical properties (i.e., temperature, moisture, pH, Bulk density, total and readily oxidizable organic carbon) in the tropical forest. [ABSTRACT FROM AUTHOR]

Fertilizer plays an important role in maintaining soil fertility, increasing yields and improving harvest quality. However, a significant portion of fertilizers are lost, increasing agricultural cost, wasting energy and polluting the environment, which are challenges for the sustainability of modern agriculture. To meet the demands of improving yields without compromising the environment, environmentally friendly fertilizers (EFFs) have been developed. EFFs are fertilizers that can reduce environmental pollution from nutrient loss by retarding, or even controlling, the release of nutrients into soil. Most of EFFs are employed in the form of coated fertilizers. The application of degradable natural materials as a coating when amending soils is the focus of EFF research. Here, we review recent studies on materials used in EFFs and their effects on the environment. The major findings covered in this review are as follows: 1) EFF coatings can prevent urea exposure in water and soil by serving as a physical barrier, thereby reducing the urea hydrolysis rate and decreasing nitrogen oxide (NO x ) and dinitrogen (N 2 ) emissions, 2) EFFs can increase the soil organic matter content, 3) hydrogel/superabsorbent coated EFFs can buffer soil acidity or alkalinity and lead to an optimal pH for plants, and 4) hydrogel/superabsorbent coated EFFs can improve water-retention and water-holding capacity of soil. In conclusion, EFFs play an important role in enhancing nutrients efficiency and reducing environmental pollution. [ABSTRACT FROM AUTHOR]

Calcium nitrate (Ca(NO 3) 2) addition can be used to control the release of phosphorus from sediments, however it can also cause an increase in the concentration of nitrate‑nitrogen (NO 3 −-N) in the water column. The risk of NO 3 −-N release from the Ca(NO 3) 2 -injected sediments may be reduced by the placement of the anion exchange resin (AER) capping layer. In this study, the effectiveness of the combined use of Ca(NO 3) 2 addition and AER capping to prevent the liberation of phosphorus from sediments was investigated, and the reduction of the risk of NO 3 −-N released from the Ca(NO 3) 2 -injected sediment by the AER capping was also evaluated. The combined application of Ca(NO 3) 2 addition and AER capping could tremendously reduce the amount of soluble reactive phosphorus (SR-P) in the overlying water, with SR-P reduction rates of 75.9–98.7%. Furthermore, it could cut down the contents of high-resolution diffusive gradients in thin films (DGT)-labile phosphorus in the sediments, resulting in the formation of phosphorus static layer in the upper sediments. The combined treatment using Ca(NO 3) 2 and AER had a relatively small effect on the contents of mobile phosphorus in the sediments, but it could greatly increase the amount of residual phosphorus in the top 30 mm sediments (increased by 27.7–42.9%). The amount of NO 3 −-N in the overlying water under the action of the combined treatment method using Ca(NO 3) 2 and AER was much lower than that under the action of the single Ca(NO 3) 2 treatment during the early stage of sediment remediation. In conclusion, the combined use of Ca(NO 3) 2 addition and AER capping is a more promising strategy for the control of sedimentary phosphorus release than the single use of Ca(NO 3) 2 addition from the point of view of both the control efficiency of P release from sediments and the releasing risk of the added nitrate. Unlabelled Image • Anion exchange resin (AER) was applied to cover nitrate-injected sediments. • AER capping reduced nitrate-nitrogen releasing risk of Ca(NO 3) 2 -added sediments. • Ca(NO 3) 2 addition and AER capping were simultaneously used to remediate sediments. • Combined use effectively controlled phosphorus release from sediments. [ABSTRACT FROM AUTHOR]

This work prepared lanthanum hydroxide (La-OH) and magnetite/lanthanum hydroxide composite (Mag-La-OH), and then La-OH and Mag-La-OH were used as sediment amendments to immobilize phosphorus (P) in sediments. The immobilization efficiency of mobile P (Mob P) and bioavailable P (BIO-P) in sediments by La-OH and Mag-La-OH was investigated. Results showed that the addition of La-OH into sediment resulted in the transformation of loosely adsorbed P (LA-P) and redox sensitive P (RS-P) to sodium hydroxide extractable P (OH-P) and hydrochloride extractable P (H P) in the sediment, while the addition of Mag-La-OH into sediment led to the transformation of LA-P, RS-P and H P to OH-P and residual P (RES P) in the sediment. Both La-OH and Mag-La-OH can effectively immobilize Mob-P (LA-P + RS-P) in sediments, but La-OH had a higher Mob-P immobilization capacity than Mag-La-OH. The amendment of sediments with La-OH and Mag-La-OH both can reduce the amounts of different types of BIO-P including water soluble P (WA-P), algal available P (AL-P) and Fe oxide-paper extractable P (FE-P) in the sediments, and La-OH had a higher BIO-P immobilization capacity than Mag-La-OH. The immobilization of Mob-P in sediments by Mag-La-OH could be described by the equation: W = 0.333 × (∆Mob-P)-14.4, where ∆Mob-P (mg/kg) is the amount of Mob-P bounded in sediments and W (%) is the Mag-La-OH dosage. The immobilization of FE-P in sediments by Mag-La-OH could be described by the equation: W = 0.380 × (∆FE-P) + 1.14, where ∆FE-P is the amount of FE-P bounded in sediments. Considering that Mag-La-OH can be retrieved from the water bodies under the action of external magnetization fields after its application, Mag-La-OH could have high potential to be used as an amendment for the immobilization of Mob-P and BIO-P in sediments. Unlabelled Image • La(OH) 3 and magnetite/La(OH) 3 composite (MLa(OH) 3) were prepared and characterized. • La(OH) 3 and MLa(OH) 3 were used to immobilize mobile P (P m) and bioavailable P (BAP). • Both La(OH) 3 and MLa(OH) 3 were effective for immobilizing P m and BAP. • La(OH) 3 had higher immobilization ability for P m and BAP than MLa(OH) 3. • Considering retrievability, MLa(OH) 3 is more promising for immobilizing P m and BAP. [ABSTRACT FROM AUTHOR]

Microplastics (MPs) are a hazardous pollutant of world concern that threaten aquatic organisms and ecosystems. In this study, we chose the worldwide-distributed shrimp Litopenaeus vannamei as a model and investigated the toxicological effects of five types of MPs on L. vannamei using several omics approaches. After 14 days of exposure to MPs, obvious intestinal microbiota variation was observed, such as increased abundances of Bacteroidetes and Proteobacteria and a decreased abundance of Firmicutes. Specifically, MPs induced several putative opportunistic pathogens and reduced lactic acid- and short-chain fatty acid-producing bacteria. Alternatively, MPs altered haemolymph proteome profiles, but the five types of MPs had different effects on the enriched pathways and the expression of immune-related proteins. Furthermore, MPs also caused haemolymph metabolite variation, especially in amino acid and alpha-linolenic acid metabolism, and 28 differential metabolites were altered in the five MP-treated groups. Changes in intestinal bacteria were correlated with the haemolymph proteins and metabolites of the shrimp. Overall, these results reveal the toxicological effects of MPs on the intestinal microbiota and the host's immunity and metabolism in shrimp. Unlabelled Image • Intestinal microbiota and haemolymph protein and metabolite molecules were affected. • Intestinal lactic acid and short chain fatty acid producing bacteria abundance were decreased. • Different types of MPs changed haemolymph protein profiles differently. • Haemolymph amino acids and alpha-linolenic acid metabolism were altered. • Several stress-related protein and metabolite markers were identified. [ABSTRACT FROM AUTHOR]

Aerosols are an important contributor to global atmospheric changes and have critical effects on the climate system. Regionally, aerosols in central Asia comprise a significant portion of global aerosols. Based on aerosol optical depth (AOD)Level 2 daily product data and land cover type product data, the long-term AOD characteristics of six major land use/cover types and their relationships with landscape metrics are discussed. Contribution analysis is applied to quantitatively estimate the effects of land use/cover on regional AOD over central Asia. The results show that series of daily AODs over six land uses/covers display remarkable annual cyclic variations and obvious seasonal changes. The annual average AODs for barren land and cropland are highest, followed by regional AODs. There are different frequencies and times of occurrence for high AOD values of various land types. Urban areas are one of the major contributors to the regional atmosphere in winter; grasslands have a great influence on regional AOD decreases. Barren land always has a high contribution to the regional AOD. The land use types affected by anthropogenic activities were smaller contributors to regional aerosols than barren lands affected by climate factors. This paper advances the understanding of relationship between aerosols and land use/cover and facilitates land use decision making. Unlabelled Image • Daily AOD data of six land types are obtained from 2007 to 2017 • Variation characteristics of six major land use/cover types AOD are revealed • Frequencies and times of occurrence for high AOD values vary in diverse land types • Further quantitative calculations show the LUCCs contributors to the regional AOD [ABSTRACT FROM AUTHOR]

The environmental ecological risks of dissolved organic matter (DOM) extracted from diverse sewage treatment plants and processes have attracted urgent attention. The correlations between the toxicity of DOM and its compositions or properties deserved to be explored to evaluate the environmental risk. Human liver cancer (HepG2) and normal liver (L02) cell lines were used in in vitro experiments evaluating the environmental risks of dissolved organics discharged from secondary and advanced sewage treatment processes. Organics extracted from dewatered sludge were also tested. Elemental compositions were determined and optical characterization was performed. The results indicated that the organics in the effluent from anaerobic-anoxic-oxic processes contained more oxygen-containing groups and hydrophilic substances than those in other types of effluent. The sludge extracts showed the greatest cytotoxicity, followed by the effluent from secondary treatment and then the effluent from an advanced treatment process. The sludge extracts inhibited cell proliferation while the other effluents promoted it at a 5 mgC/L concentration. The organics discharged from secondary and advanced treatment processes induced relatively little production of reactive oxygen species. That stimulated cell self-repair and free radical scavenging and consequently resulted in cell proliferation with the cell lines tested. Oxygen-containing groups in the dissolved organics promoted cell proliferation and ROS removal. The atomic ratios and UV spectroscopy indices contributed mainly to the cell viability among the positive indicators. These results provide theoretical basis for managing the ecological risks posed by dissolved organics released from sewage treatment processes. Unlabelled Image • The environmental risk of DOM from effluent was evaluated using in vitro cell model. • DOM extracted from A2/O effluent contained more oxygen-containing substances. • Oxidative damage plays an important role in DOM-induced cell apoptosis. • The elemental composition of DOM correlates with its cytotoxicity. [ABSTRACT FROM AUTHOR]

• Material boundary layer height Hc was proposed. • Hc was relatively lower than Hθ and Hu , despite a high bias caused by the residual layer, multilayer aerosol structure, or lower inversion. • Hc , Hθ , Hu and Ht differed greatly on clean days. During the pollution process, Hc , Hθ and Ht were almost 700 m. The planetary boundary layer (PBL) height mainly determines the environmental capacity for the diffusion of atmospheric pollutants, and has always been a hot issue in the study of air pollution. However, there still remains great uncertainty, partly because different PBL heights definitions and the PBL heights are obtained by various measurement instruments. Pollutants are the substances emitted, different from the atmospheric background physical properties such as wind, temperature and turbulence flux that always exist even without pollution. It is very important to distinguish PBL heights obtained from wind, temperature, turbulence quantities and the concentration of pollutants. In this paper, we express the PBL heights determined on the above four parameters as Hu, H θ , Ht and Hc respectively, and compare them during a heave haze pollution process in Beijing using observation data and simulation results. The comparison results show that: (1) H θ , namely the inversion layer height, decreased from approximately 1250 m to 450 m from 26 to 30 December, resulting in deteriorating pollution situation. Hc, calculated by lidar and characterizes the maximum depth of vertical diffusion of particulates, also dropped below 500 m, and on the whole, the values of Hc estimated by gradient method and H θ were in good agreement; (2) Generally, Hc was relatively lower than H θ and Hu , despite a high bias caused by the existence of the residual layer, multilayer aerosol structure, or lower inversion; (3) Ht estimated from turbulence quantities simulated by WRF model mainly approximated Hu , H θ and Hc in the daytime during haze pollution, however for the nocturnal boundary layer height in the winter, Ht was seriously underestimated. The averaged PBL heights according to the pollution level showed that Hc , H θ , Hu and Ht differed greatly on clean days, and the maximum PBL height Hu exceeded 1400 m. On clean days, the inversion intensities observed were lower, so the blocking effect of the inversion layer to pollutant diffusion was not strong enough, H θ (886 m) deviated from Hc (1111 m). However, Hc and Ht were very close, approximately 1100 m. The decrease of PBL height led to heavy pollution, Hc , H θ and Ht were almost 700 m. Hu was slightly higher and reduced by about 450 m during heavy pollution. The detailed analyses and comparisons of the PBL height from different variables can help improve the rational application of different methods in the determination of PBL height. [ABSTRACT FROM AUTHOR]