Enhanced Species Diversity Unlocked by Habitat Conservation in Agricultural Landscapes: New Perspectives on Ecological Weed Management and Sustainable Intensification—Species Diversity and Habitat Conservation

The impulse to remain profitable by increasing agricultural production levels in view of the greater demand for food, provided impetus to production intensification. The aim of this review is to summarise current literature, reporting specifically on the impact of production intensification on habitats and yield constraints caused by weeds. Secondly, in alleviating these effects over the short term, ecological measures that enhance species diversity in conserved habitats and promote semi-natural habitats in the agricultural landscape, are discussed. In large-scale intensive agriculture, weed control is predominantly rooted in agrochemical applications in the form of herbicides. Long lasting intensive agricultural practices show discord both with the promotion of the biodiversity of microbes belowground and aboveground and with organisms involved in the breaking down of plant material. The presence of native species in the surroundings, in combination with hedgerows and field margins, with a comparatively intricate and balanced variety of plants in a sheltered environment, are essential for settlement of benign insects, particularly in the face of intensive agricultural production. The promising tactic of advantageous seed predators enables decreased herbicide applications. Crop mosaics arranged to advance compatibility at the landscape scale are important to bolster pollination services and insect management, while ecological variety in the surroundings acts as a safety net for habitat diversity. Weed control in combination with different tactics of vegetation use, comprising cover cropping, hedgerows and field margins, sets up safe havens in the landscape, and improves the diffusion of complementary life forms. Field margins perform a meaningful natural function as point of provision for forage, safe havens and distribution passageways for pollinators and insect predators. Production practices that promote more heterogeneity and combine high density semi-natural safe havens and habitat conservation in agro ecosystems are beneficial to species diversity across trophic levels and contribute to agricultural production stability and food safety.

Comparison of Di-n-methyl Phthalate Biodegradation by Free and Immobilized Microbial Cells

To compare the biodegradation of di-n-methyl pathalate by free and immobilized microbial cells. Methods The enrichment and isolation technique was used to isolate the microorganism. The PAV-entrapment method was utilized to immobilize the microorganisms. The scanning electron microscophy (SEM) was used to observe the growth and distribution of microbial cells immobilized inside the PVA bead gels. The GC/MS method was used to identify the main intermediates of DMP degradation. Results The microbial cells could grow quite well in PVA gel. The metabolic pathway did not change before and after immobilization of the microbial cells. The degradation rate of immobilized cells was higher than that of free cells. Conclusion The immobilized microbial cells possess advantages than free cells when applied to the biodegradation of toxic organic pollutants.

Reclaimation of petroleum-based wastewater by noval ozone immobilized biological activated carbon process

Wastewater reclamation in the petroleum industries in Northern China is important because of the shortage of water resource. Conventional treatment technology used：in treating petroleum-based wastewater, namely the 3-phase biological process, typically removes COD, BODI grease, volatile hydrobenzenes, cyanides, sulfides and suspended solids. However, the process is often ineffective in ammonia-nitrogen removal, and thus the treated effluent quantity can＇ t meet the required standards for reuse. This paper investigated a novel ozone immobilized biological activated carbon（O3-IBAC） process for ammonia nitrogen removal from petroleum-based wastewater. Operated at a HRT （ Hydraulic Retention Time） of 15 minutes in IBACI and 27 minutes in IBAC2, the O3-IBAC process achieved ammonia nitrogen removal efficiency of 91%. In addition, the removal efficiencies 6f COD, volatile hydrobenzenes, suspended solids, turbidity and petroleum-based micropollutants were all above 90%. Competition between the autotrophs and heterotrophs was observed, which was indicated by an increase of ammonia nitrogen removal with a decrease of COD removal, and vise versa. Nitrite accumulation in IBACI followed by erobic shortcut denitrification in IBAC2 led to 28% of the Total Nitrogen removal efficiency. Pollutant reduction in＇ the IBAC process was achieved by a rapid physical adsorption and biodegradation on the activated carbon, which effectively retained the pollutants in the system despite the short hydraulic retention time.

Biogeochemical cycling of metals impacting by microbial mobilization and immobilization

Microbial mobilization and immobilization processes can affect the bioavailability and mobility of metals thereby influencing their toxicity and can therefore be utilized to treat solid and liquid wastes contaminated by metals. However, the microbial mobilization and immobilization of metals depends on the microbial metabolism, the environment conditions. In this review, mobilization and immobilization of metals are discussed with regard to the presence and function of involved microorganisms and in relation to applications such as bioleaching. Furthermore, the biosorption process is evaluated as a possible approach for microbial immobilization of metal on the basis of four mechanisms：（1） physical adsorption,（2） ion exchange,（3） complexation, and（4） microprecipitation. In addition, sulfide precipitation by sulfate reducing bacteria was included as an example of an application of microbial immobilization. Based on the evaluation and recommendations in this paper, bioremediation strategies for metals can be improved thus increasing the opportunity for field applications.

Preparation and characterization of a novel microorganism embedding material for simultaneous nitrification and denitrification

A novel microorganism embedding material was prepared to enhance the biological nitrogen removal through simultaneous nitrification and denitrification. Polyvinyl alcohol （PVA）, sodium alginate （SA） and cyclodextrin （CD） were used to compose gel bead with embedded activated sludge. The effects of temperature, CD addition and concentrations of PYA and SA on nitrogen removal were evaluated. Results show that the gel bead with CD addition at 30℃contributed to the highest nitrogen removal efficiency and nitrogen removal rate of 85.4% and 2.08 mg·（L·h）^-1, respectively. Meanwhile, negligible NO3^- and NO2^- were observed, proving the occurrence of simultaneous nitrification and denitrification. The High-Throughput Sequencing confirms that the microbial community mainly contained Comamonadaceae in the proportion of 61.3%. Overall, CD increased gel bead＇s porosity and resulted in the high specific endogenous respiration rate and high nitrogen removal efficiency, which is a favorable additional agent to the traditional embedding material.