Integral to the urban ecosystem,greening trees provide many ecological benefits,but the active biogenic volatile organic compounds(BVOCs)they release contribute to the production of ozone and secondary organic aerosol...Integral to the urban ecosystem,greening trees provide many ecological benefits,but the active biogenic volatile organic compounds(BVOCs)they release contribute to the production of ozone and secondary organic aerosols,which harm ambient air quality.It is,therefore,necessary to understand the BVOC emission characteristics of dominant greening tree species and their relative contribution to secondary pollutants in various urban contexts.Consequently,this study utilized a dynamic enclosure system to collect BVOC samples of seven dominant greening tree species in urban Chengdu,Southwest China.Gas chromatography/mass spectrometry was used to analyze the BVOC components and standardized BVOC emission rates of each tree species were then calculated to assess their relative potential to form secondary pollutants.We found obvious differences in the composition of BVOCs emitted by each species.Ficus virens displayed a high isoprene emission rate at31.472μgC/(gdw(g dry weight)·hr),while Cinnamomum camphora emitted high volumes of D-Limonene at 93.574μgC/(gdw·hr).In terms of the BVOC emission rates by leaf area,C.camphora had the highest emission rate of total BVOCs at 13,782.59μgC/(m^(2)·hr),followed by Cedrus deodara with 5466.86μgC/(m^(2)·hr).Ginkgo biloba and Osmanthus fragrans mainly emitted oxygenated VOCs with lower overall emission rates.The high BVOC emitters like F.virens,C.camphora,and Magnolia grandiflora have high potential for significantly contributing to environmental secondary pollutants,so should be cautiously considered for future planting.This study provides important implications for improving urban greening efforts for subtropical Chinese urban contexts,like Chengdu.展开更多
The organic carbon budget in shrimp polyculture ecosystems was studied with five experimental enclosures. The results showed that: (l ) the total Organic carbon income of the ecosystems varied from 4 847. 46 to 6 15...The organic carbon budget in shrimp polyculture ecosystems was studied with five experimental enclosures. The results showed that: (l ) the total Organic carbon income of the ecosystems varied from 4 847. 46 to 6 154. 67 g, averaged (5 646. 94 t 551.09) g, the average ratio among its components, i. e., (phytoplankton production ): (periphyte production ): (feed casted) was 0. 73: 0. 11: 0. 16; (2) the total output of organic carbon varied from 3 310. 28 to 3 974. 79 g, averaged (3 644. 21 281. 44) g, the average ratio among its components, i. e., (plankton community respiration): (periphyton respiration): (benthic community): (culture animal production): (culture animal respiration) was 0. 53: 0. 19: 0. 15: 0. 04:0. 09; (3) the organic carbon accumulation varied from 1 383. 45 to 2 707. 31 g, averaged (2 002. 73 546. 76) g, which was 26% --44 % of the total organic carbon income; the sequence of organic carbon accumulation in the ecosystems of different polyculture types was Y5 (Penaeus chinensis -- Argopecten irradians) > Y7 (P. chinensis -- Taiwan red tilapia) > Y4 (P. chinensis ) > T5 (P. chinensis -- Taiwan red tilapia -- Sinonovacula constricta ) > Y6 (P. chinensis S. constricta ); (4) the average conversion rate of organic carbon income to P. chinensis was (l. 77 0. 62) % (Y6>T5 > Y4 >YS > Y7), and that to total culture animals was (2. 18 0. 79) % (T5 >Y6 > Y5 > Y4 > Y7).展开更多
基金supported by the National Natural Science Foundation of China(No.21906108)the Fundamental Research Funds for the Central Universities(No.YJ201937)+1 种基金Chengdu Science and Technology Bureau(No.2020-YF09-00051-SN)the Sichuan"1000 Plan"Scholar Program
文摘Integral to the urban ecosystem,greening trees provide many ecological benefits,but the active biogenic volatile organic compounds(BVOCs)they release contribute to the production of ozone and secondary organic aerosols,which harm ambient air quality.It is,therefore,necessary to understand the BVOC emission characteristics of dominant greening tree species and their relative contribution to secondary pollutants in various urban contexts.Consequently,this study utilized a dynamic enclosure system to collect BVOC samples of seven dominant greening tree species in urban Chengdu,Southwest China.Gas chromatography/mass spectrometry was used to analyze the BVOC components and standardized BVOC emission rates of each tree species were then calculated to assess their relative potential to form secondary pollutants.We found obvious differences in the composition of BVOCs emitted by each species.Ficus virens displayed a high isoprene emission rate at31.472μgC/(gdw(g dry weight)·hr),while Cinnamomum camphora emitted high volumes of D-Limonene at 93.574μgC/(gdw·hr).In terms of the BVOC emission rates by leaf area,C.camphora had the highest emission rate of total BVOCs at 13,782.59μgC/(m^(2)·hr),followed by Cedrus deodara with 5466.86μgC/(m^(2)·hr).Ginkgo biloba and Osmanthus fragrans mainly emitted oxygenated VOCs with lower overall emission rates.The high BVOC emitters like F.virens,C.camphora,and Magnolia grandiflora have high potential for significantly contributing to environmental secondary pollutants,so should be cautiously considered for future planting.This study provides important implications for improving urban greening efforts for subtropical Chinese urban contexts,like Chengdu.
基金the National Natural Science Foundation of China under contract! No. 39430150 National Scaling He
文摘The organic carbon budget in shrimp polyculture ecosystems was studied with five experimental enclosures. The results showed that: (l ) the total Organic carbon income of the ecosystems varied from 4 847. 46 to 6 154. 67 g, averaged (5 646. 94 t 551.09) g, the average ratio among its components, i. e., (phytoplankton production ): (periphyte production ): (feed casted) was 0. 73: 0. 11: 0. 16; (2) the total output of organic carbon varied from 3 310. 28 to 3 974. 79 g, averaged (3 644. 21 281. 44) g, the average ratio among its components, i. e., (plankton community respiration): (periphyton respiration): (benthic community): (culture animal production): (culture animal respiration) was 0. 53: 0. 19: 0. 15: 0. 04:0. 09; (3) the organic carbon accumulation varied from 1 383. 45 to 2 707. 31 g, averaged (2 002. 73 546. 76) g, which was 26% --44 % of the total organic carbon income; the sequence of organic carbon accumulation in the ecosystems of different polyculture types was Y5 (Penaeus chinensis -- Argopecten irradians) > Y7 (P. chinensis -- Taiwan red tilapia) > Y4 (P. chinensis ) > T5 (P. chinensis -- Taiwan red tilapia -- Sinonovacula constricta ) > Y6 (P. chinensis S. constricta ); (4) the average conversion rate of organic carbon income to P. chinensis was (l. 77 0. 62) % (Y6>T5 > Y4 >YS > Y7), and that to total culture animals was (2. 18 0. 79) % (T5 >Y6 > Y5 > Y4 > Y7).
