Effects of organic mineral fertiliser on heavy metal migration and potential carbon sink in soils in a karst region

Heavy metal pollution in karst mountainous area of Guizhou has spread due to the long-term exploitation of mineral resources and the improper disposal of environmentally hazardous waste. Heavy metals are characterised by non-degradation, strong toxicity, and constant accumulation, posing a grave threat to karst mountain fragile soil ecosystem. To reduce the harm caused by heavy metal pollution and damage to agricultural products, research was undertaken on the basis of previous work by simulating pot experiments on pak choi cabbage(Brassica rapa chinensis)planted in Cd-contaminated soil: different amounts of organic mineral fertilisers(OMF) compared with chemical fertiliser(CF) were used and by detecting the amount of heavy metal in the mature vegetable, a better fertilisation strategy was developed. The results showed that the Cd content in vegetables grown with CF was 23.70 mg/kg,while that of vegetables grown with OMF and bacterial inoculant was the lowest at 15.13 mg/kg. This suggests that the use of OMF and microbes in karst areas not only promotes plant growth but also hinders plant absorption of heavy metal ions in the soil. In addition, through the collection of pot leachate, the detection of water chemistrycharacteristics, and the calculation of the calcite saturation index, it was found that the OMF method also induces certain carbon sink effects. The results provide a new way in which rationalise the use of OMFs in karst areas to alleviate soil heavy metal pollution and increase soil carbon sequestration.

Effects of mineral-organic fertilizer on the biomass of green Chinese cabbage and potential carbon sequestration ability in karst areas of Southwest China

The karst mountain areas of Southwest China contain barren farmland soils and suffer from nutritional and water deficiencies that affect crop productivity. Hence,it is imperative to apply suitable fertilizers to restore soil fertility and maintain crop yield. The aim of this study is to investigate the effects of mineral-organic fertilizer(MOF)made of potassic rock and organic waste on the growth of crops. For this purpose, green Chinese cabbage grown using three different fertilization methods including MOF,inorganic fertilizer(IF), and a control was evaluated. We determined soil water content, agronomic characteristics,and biomass of green Chinese cabbage in different treatments. Furthermore, surface runoff from the pot experiments and soil leachate from pot experiments were collected to determine water temperature, pH, and cation and anion concentrations. The results demonstrate thatMOF can improve the soil water-holding capacity of soil,and the basic agronomic characteristics of the cabbage treated with MOF were superior to those with IF. Using MOF can promote the increase in cabbage biomass.Additionally, the concentration of inorganic carbon(largely in the form of HCO_3^-) in surface runoff water treated by MOF was higher than the other treatments, establishing carbon sequestration potential. This work provides a novel and environmentally friendly fertilization pattern in karst areas, which will improve crop yield and also increase the carbon sequestration potential of crops.

Adsorption removal of roxarsone, arsenite(Ⅲ),and arsenate(Ⅴ) using iron-modified sorghum straw biochar and its kinetics

Arsenic(As)contamination in groundwater is a major problem in many countries,which causes serious health issues.In this paper,a novel method has been developed for the simultaneous removal of ROX and As(Ⅲ/Ⅴ)using the modified sorghum straw biochar(MSSB).The MSSB was characterized by X-ray diffraction,scanning electron microscopy,Fourier Transform Infrared,and Brunauer–Emmet–Teller(BET)surface area.The removal performance of MSSB for ROX,arsenite[As(Ⅲ)],and arsenate(As(Ⅴ))was investigated using batch experiments.At pH of 5,the arsenic concentration of 1.0 mg/L,adsorbent dose of 1.0 g/L,the maximum adsorptioncapacities of ROX,As(Ⅲ),and As(Ⅴ)were 12.4,5.3,and 23.0 mg/g,respectively.The adsorption behaviors were fit well with the Langmuir and the pseudo-second-order rate model.The results showed that MSSB acted as a highly effective adsorbent to simultaneously remove the composite pollution system consisted of ROX and As(Ⅲ/Ⅴ)in aqueous solutions,providing a promising method in environmental restoration applications.

CO_2 seasonal variation and global change: Test global warming from another point of view

CO2 and temperature records at Mauna Loa, Hawaii, and other observation stations show that the correlation between CO2 and temperature is not significant. These stations are located away from big cities, and in various latitudes and hemi-spheres. But the correlation is significant in global mean data. Over the last five decades, CO2 has grown at an accelerating rate with no corresponding rise in temperature in the stations. This discrepancy indicates that CO2 probably is not the driving force of temperature change globally but only locally （mainly in big cities）. We suggest that the Earth＇s atmospheric concentration of CO2 is too low to drive global temperature change. Our empirical perception of the global warming record is due to the urban heat island effect： temperature rises in areas with rising population density and rising industrial activity. This effect mainly occurs in the areas with high population and intense human activities, and is not representative of global warming. Regions far from cities, such as the Mauna Loa highland, show no evident warming trend. The global monthly mean temperature calculated by record data, widely used by academic researchers, shows R2=0.765, a high degree of correlation with CO2 . However, the R2 shows much less significance （mean R2=0.024） if calculated by each record for 188 selected stations over the world. This test suggests that the inflated high correlation between CO2 and temperature （mean R2=0.765-0.024=0.741） used in reports from the Intergovernmental Panel on Climate Change （IPCC） was very likely produced during data correction and processing. This untrue global monthly mean temperature has created a picture： human emission drives global warming.

The safflower MBW complex regulates HYSA accumulation through degradation by the E3 ligase CtBB1

The regulatory mechanism of the MBW(MYB-bHLH-WD40) complex in safflower(Carthamus tinctorius) remains unclear. In the present study,we show that the separate overexpression of the genes CtbHLH41, CtMYB63, and CtWD40-6 in Arabidopsis thaliana increased anthocyanin and procyanidin contents in the transgenic plants and partially rescued the trichome reduction phenotype of the corresponding bhlh41, myb63,and wd40-6 single mutants. Overexpression of CtbHLH41, CtMYB63, or CtWD40-6 in safflower significantly increased the content of the natural pigment hydroxysafflor yellow A(HYSA)and negatively regulated safflower petal size.Yeast-two-hybrid, functional, and genetic assays demonstrated that the safflower E3 ligase CtBB1(BIG BROTHER 1) can ubiquitinate CtbHLH41,marking it for degradation through the 26S proteasome and negatively regulating flavonoid accumulation. CtMYB63/CtWD40-6 enhanced the transcriptional activity of CtbHLH41 on the CtDFR(dihydroflavonol 4-reductase) promoter.We propose that the MBW-CtBB1 regulatory module may play an important role in coordinating HYSA accumulation with other response mechanisms.

γ-聚谷氨酸水凝胶的制备及其应用

γ-聚谷氨酸水凝胶是以γ-聚谷氨酸为单体,经交联形成的一种具有三维网状结构的材料。由于分子中含有大量羧基,使其具有超强的吸水能力。由于γ-聚谷氨酸源于微生物,因此其水凝胶是一种生物相容性良好的环境友好型多功能材料,可应用于生物医药、日化、环境及纺织等多个领域。本文综述了近年来制备γ-聚谷氨酸水凝胶的三种交联方法:物理交联、化学交联和酶法交联,对γ-聚谷氨酸水凝胶在组织工程、超级电容器和纺织方面的应用进行总结,并对其未来的发展作了展望。

Evaluation of the four potential Cretaceous-Paleogene (K-Pg) boundaries in the Nanxiong Basin based on evidences from volcanic activity and paleoclimatic evolution

Determining the location of the Cretaceous-Paleogene(K-Pg) boundary in terrestrial strata is highly significant for studying the evolution of terrestrial ecosystems at the end of the Cretaceous(especially the extinction of non-avian dinosaurs). At present, research on terrestrial K-Pg boundaries worldwide is concentrated in the middle and high latitudes, such as North America and Northeast China. Although many studies have also been carried out in the Nanxiong Basin, located at low latitudes(which has become the standard for dividing and comparing the continental K-Pg stratigraphy in China), many researchers have proposed four possible boundaries from different perspectives. Therefore, the exact location remains to be determined. In this study, the total mercury(Hg) content, environmental magnetism, geochemistry, and other parameters for the samples collected near the four boundaries were determined and compared with existing records. Results indicated that: 1) The total Hg content significantly increased in the upper part of the Zhenshui Formation and Pingling part of the Shanghu Formation with sharp fluctuations. As per latest dating results of Deccan Traps, the significantly high Hg value was attributed to the Deccan Traps eruption. Boundary 1 was located in the middle of the Hg anomaly interval, which was consistent with the relationship between the global K-Pg boundary and time of volcanic eruption. 2) The reconstructed paleoclimate evolution curve revealed that the red sediments in the basin recorded the late Maastrichtian warming event(66.2 Ma). Regarding the relationship between the four boundaries and this warming event, only boundary 1 was found to be closest to the real K-Pg boundary of the Nanxiong Basin.

Variations regularity of microorganisms and corrosion of cast iron in water distribution system

Corrosion, one of the most common problems of metal pipe for water supply, generally leads to poor water quality, bacteria proliferation, water capacity decrease and other problems. As microorganisms affect corrosion by changing the characteristics of metal surface, the mechanism of microbial corrosion still remains unclear. The corrosion behavior of ductile cast iron is implemented in the dynamic flow and static conditions, in which variations of water quality and microbial community are analyzed in details. The results show that if the corrosion rate of ductile cast iron decreases, the corrosion of cast iron will result in a lower DO and a higher total iron in bulk water. The number of microorganisms is not a decisive factor of corrosion, even though the counts of bacteria had a close relationship with DO. On the basis of the detection of the 10 kinds of nitratereducing bacteria by Miseq sequencing, NRB of the biofilm biomass accounts for 18.3% on the 30 th day and 20.5% on the 55 th day. Even though aerobic NRBs go into the biofilm later than the facultative anaerobic NRBs, the growth of the anaerobic NRBs is not affected.

Rock-magnetic characteristics and mechanisms of the Titel loess-paleosol sequence in northern Serbia since late Middle Pleistocene

The changing pattern of magnetic characteristics in eastern European loess deposits is the most similar across the world to that of the Chinese Loess Plateau,both of which are dominated by the strength of pedogenesis.Hence a systematical study to the rock magnetism of eastern European loess is not only helpful for understanding the paleoclimatic information preserved by themselves,but also beneficial for promoting the cognition of the pedogenic mechanism in loess records.In this study,a detailed rock-magnetic analysis of seventy loess/paleosol samples,taken from the Titel Loess Plateau in northern Serbia,is carried out for a better understanding of the magnetic records since late Middle Pleistocene.The results provide us some implications.First,the magnetic susceptibility values of the paleosols in the Titel loess-paleosol sequence are generally less than 100×10^(-8)m^(3)kg^(-1),significantly lower than those of the loess sections in the Chinese Loess Plateau,even though they are under similar climatic conditions.However,the behaviors of the parameters related to the distributions of magnetic particles in these two regions are similar.The difference in the contents of ferrimagnetic minerals is the leading reason that caused the difference in their magnetic characteristics,but the mechanism is still open to study.Second,based on the analysis of thermomagnetic curves,a gradually increasing trend of the relative contents of maghemite over the last four glacial-interglacial cycles is identified.The realization of thermally unstable maghemite from Chinese loess leads us to speculate that the long-term increasing trend of the relative contents of maghemite in Titel loess-paleosol sequence likely is a mineralogical response to the progressive enhancement of continental climate in the Pannonian Basin since the Middle Pleistocene.