Surface ozone(O_(3))poses significant threats to public health,agricultural crops,and plants in natural ecosystems.Global warming is likely to increase future O_(3)mainly by altering atmospheric photochemical reaction...Surface ozone(O_(3))poses significant threats to public health,agricultural crops,and plants in natural ecosystems.Global warming is likely to increase future O_(3)mainly by altering atmospheric photochemical reactions and enhancing biogenic volatile organic compound(BVOC)emissions.To assess the impacts of the future 1.5 K climate target on O_(3)concentrations and ecological O_(3)exposure in China,numerical simulations were conducted using the CMAQ(Community Multiscale Air Quality)model during April-October 2018.Ecological O_(3)exposure was estimated using six indices(i.e.,M7,M24,N100,SUM60,W126,and AOT40f).The results show that the temperature rise increases the MDA8 O_(3)(maximum daily eight-hour average O_(3))concentrations by∼3 ppb and the number of O_(3)exceedance days by 10-20 days in the North China Plain(NCP),Yangtze River Delta(YRD),and Sichuan Basin(SCB)regions.All O_(3)exposure indices show substantial increases.M24 and M7 in eastern and southern China will rise by 1-3 ppb and 2-4 ppb,respectively.N100 increases by more than 120 h in the surrounding regions of Beijing.SUM60 increases by greater than 9 ppm h^(−1),W126 increases by greater than 15 ppm h^(−1)in Shaanxi and SCB,and AOT40f increases by 6 ppm h^(−1)in NCP and SCB.The temperature increase also promotes atmospheric oxidation capacity(AOC)levels,with the higher AOC contributed by OH radicals in southern China but by NO_(3)radicals in northern China.The change in the reaction rate caused by the temperature increase has a greater influence on O_(3)exposure and AOC than the change in BVOC emissions.展开更多
The objective of this study is to select and characterize the candidate for synchronous water purification and lipid production from eight freshwater microalgae strains （Chlorella sp. HQ, C. emersonii, C. pyrenoidosa...The objective of this study is to select and characterize the candidate for synchronous water purification and lipid production from eight freshwater microalgae strains （Chlorella sp. HQ, C. emersonii, C. pyrenoidosa, C. vulgaris, Scenedesmus dimorphus, S. quadricauda, S. obiquus, Scenedesmus sp. LX1）. The strains Chlorella sp. HQ, C. pyrenoidesa, and S. obliquus showed superiority in biomass accumulation, while the top biomass producers did not correspond to the top lipid producers. S. quadricauda achieved higher lipid content （66.1%）, and Chlorella sp. HQ and S. dimorphus ranked down in sequence, with lipid content above 30%. Considering nutrient removal ability （total nitrogen （TN）： 52.97%; total phosphorus （TP）： 84.81%）, the newly isolated microalga Chlorella sp. HQ was the possible candidate for water purification coupled with lipid production. To further investigate the lipid producing and nutrient removal mechanism of candidate microalga, the ultra structural changes especially the lipid droplets under different water qualities （different TN and TP concentrations） were characterized. The results elucidate the nutrient-deficiency （TN： 3.0 mg·L^-1; TP： 0.3 mg·L^-1） condition was in favor of forming lipid bodies in Chlorella sp. HQ at the sub-cellular level, while the biomass production was inhibited due to the decrease in chloroplast number which could further suppress the nutrient removal effect. Finally, a two- phase cultivation process （a nutrient replete phase to produce biomass followed by a nutrient deplete phase to enhance lipid content） was conducted in a photo-bioreactor for Chlorella sp. HQ to serve for algae-based synchronous biodiesel production and wastewater purification.展开更多
基金supported by the National Natural Science Foundation of China[grant numbers 42277095 and 42021004].
文摘Surface ozone(O_(3))poses significant threats to public health,agricultural crops,and plants in natural ecosystems.Global warming is likely to increase future O_(3)mainly by altering atmospheric photochemical reactions and enhancing biogenic volatile organic compound(BVOC)emissions.To assess the impacts of the future 1.5 K climate target on O_(3)concentrations and ecological O_(3)exposure in China,numerical simulations were conducted using the CMAQ(Community Multiscale Air Quality)model during April-October 2018.Ecological O_(3)exposure was estimated using six indices(i.e.,M7,M24,N100,SUM60,W126,and AOT40f).The results show that the temperature rise increases the MDA8 O_(3)(maximum daily eight-hour average O_(3))concentrations by∼3 ppb and the number of O_(3)exceedance days by 10-20 days in the North China Plain(NCP),Yangtze River Delta(YRD),and Sichuan Basin(SCB)regions.All O_(3)exposure indices show substantial increases.M24 and M7 in eastern and southern China will rise by 1-3 ppb and 2-4 ppb,respectively.N100 increases by more than 120 h in the surrounding regions of Beijing.SUM60 increases by greater than 9 ppm h^(−1),W126 increases by greater than 15 ppm h^(−1)in Shaanxi and SCB,and AOT40f increases by 6 ppm h^(−1)in NCP and SCB.The temperature increase also promotes atmospheric oxidation capacity(AOC)levels,with the higher AOC contributed by OH radicals in southern China but by NO_(3)radicals in northern China.The change in the reaction rate caused by the temperature increase has a greater influence on O_(3)exposure and AOC than the change in BVOC emissions.
基金This research was supported by the Beijing Nova and Leading Talents Cultivation Program （No. Z1511000003150147） and the National Natural Science Foundation of China （Grant No. 51571034）.
文摘The objective of this study is to select and characterize the candidate for synchronous water purification and lipid production from eight freshwater microalgae strains （Chlorella sp. HQ, C. emersonii, C. pyrenoidosa, C. vulgaris, Scenedesmus dimorphus, S. quadricauda, S. obiquus, Scenedesmus sp. LX1）. The strains Chlorella sp. HQ, C. pyrenoidesa, and S. obliquus showed superiority in biomass accumulation, while the top biomass producers did not correspond to the top lipid producers. S. quadricauda achieved higher lipid content （66.1%）, and Chlorella sp. HQ and S. dimorphus ranked down in sequence, with lipid content above 30%. Considering nutrient removal ability （total nitrogen （TN）： 52.97%; total phosphorus （TP）： 84.81%）, the newly isolated microalga Chlorella sp. HQ was the possible candidate for water purification coupled with lipid production. To further investigate the lipid producing and nutrient removal mechanism of candidate microalga, the ultra structural changes especially the lipid droplets under different water qualities （different TN and TP concentrations） were characterized. The results elucidate the nutrient-deficiency （TN： 3.0 mg·L^-1; TP： 0.3 mg·L^-1） condition was in favor of forming lipid bodies in Chlorella sp. HQ at the sub-cellular level, while the biomass production was inhibited due to the decrease in chloroplast number which could further suppress the nutrient removal effect. Finally, a two- phase cultivation process （a nutrient replete phase to produce biomass followed by a nutrient deplete phase to enhance lipid content） was conducted in a photo-bioreactor for Chlorella sp. HQ to serve for algae-based synchronous biodiesel production and wastewater purification.
