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6 results on '"Gong, Chunjuan"'

4. Application of cold-adaptive Pseudomonas sp. SDR4 and Mortierella alpina JDR7 co-immobilized on maize cob in remediating PAH-contaminated freeze-thawed soil

Author

Zhenli He, Dan Su, Gong Chunjuan, and Pu Yu

Subjects
biology, Chemistry, Soil pollution, Microorganism, Pseudomonas, Remediation, Phenanthrene, Contamination, biology.organism_classification, Soil contamination, Environmental sciences, Organic contaminants, Abbreviations, PAHs, Polycyclic aromatic hydrocarbons, chemistry.chemical_compound, Environmental chemistry, polycyclic compounds, Pyrene, Degradation (geology), GE1-350, Mortierella, Immobilized microorganisms, Cold regions
Abstract

There are large areas of contaminated soils with low- and medium-concentration of polycyclic aromatic hydrocarbons (PAHs) in the coldest regions of the earth, potentially threatening ecological safety and human health. Using maize cobs (MC) as the carrier, two cold-adaptive PAHs-degrading microorganisms, bacterial (Pseudomonas sp., SDR4) and fungal (Mortierella alpine, JDR7) strains were co-immobilized. The degradation characteristics of phenanthrene (Phe), pyrene (Pyr) and benzo[a]pyrene (BaP) in freeze-thawed soil by both co-immobilized and free microorganism were studied. The removal rate of Phe, Pyr and BaP using the co-immobilized fungal-bacterial consortium within 60 d was 59.2±3.7%, 46.6±3.3%, and 36.8±2.7%, respectively, which was obviously higher than that of free fungal-bacterial consortium in the same time. Ten percent (w/w) was the optimal amount of inoculum for PAH degradation in the co-immobilized fungal-bacterial consortium. Under low-temperature conditions, when the initial concentration of PAH was between 10-100 mg•kg−1, the immobilized cold-adaptive fungal-bacterial consortium displayed the desired degradation of PAHs. The scanning electronic microscope (SEM) observation and mass transmission showed that the microstructure of co-immobilized mixed system was beneficial to the growth of SDR4 and JDR7 at low temperature. These results imply that the cold-adaptive fungal-bacterial consortium, co-immobilized on MC, has the potential for application in remediating PAH contaminated soil under the freeze-thawing environment.

Published
2021

6. Effects of Soil Nitrogen Addition on Crown CO 2 Exchange of Fraxinus mandshurica Rupr. Saplings.

Author

Gong, Chunjuan, Wang, Anzhi, Yuan, Fenghui, Liu, Yage, Cui, Chen, Zhu, Kai, Guan, Dexin, and Wu, Jiabing

Subjects
NITROGEN in soils, CARBON dioxide, ATMOSPHERIC nitrogen, ASH (Tree), CARBON cycle, GEOLOGIC hot spots
Abstract

The impact of atmospheric nitrogen deposition on carbon exchange between forest and atmosphere is one of the research hotspots of global change ecology, past researchers have extensively studied the impacts on leaf level, while the impacts on crown CO2 exchange are still unclear. Therefore, we explored the impacts of different nitrogen addition levels on crown CO2 exchange of Fraxinus mandshurica saplings and their responses to the changes of major meteorological factors (photosynthetically active radiation, PAR; vapor pressure deficiency, VPD; and air temperature, Tair) with a novel automated chamber system. There are four levels of nitrogen addition treatments: control (no nitrogen addition, CK), 23 (low nitrogen addition, LN), 46 (medium nitrogen addition, MN), and 69 kgN·hm−2·a−1 (high nitrogen addition, HN). Our results showed that all nitrogen addition treatments increased daily average and accumulated gross primary production (GPP), crown respiration (R), and net crown CO2 exchange (Ne), especially at medium and high nitrogen levels. Similarly, maximum net photosynthetic rate (Nemax) and apparent quantum efficiency (α) were promoted. The change of Ne with PAR, Tair, and VPD showed that nitrogen addition postponed the appearance of photosynthesis midday depression. In addition, the monthly accumulation of R with all nitrogen addition treatments showed an increasing trend (June to July), and then decreased (July to September) during the growing season, while the Ne and GPP decreased gradually with seasonal vegetation senescence. Finally, the crown shifted from carbon sink to carbon source at the end of the growing season, however, the change under high nitrogen treatment occurred 3 days later. The crown CO2 exchange measurements provide a new perspective to better understand the response of forest ecosystem CO2 exchange to elevated nitrogen deposition and provide a basis for related carbon model parameter correction under the influence of nitrogen deposition. [ABSTRACT FROM AUTHOR]

Published
2021
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