Ridgetail white prawn （Exopalaemon carinicauda） are of significant economic importance in China where they are widely cultured. However, there is little information on the basic biology of this species. We evaluated...Ridgetail white prawn （Exopalaemon carinicauda） are of significant economic importance in China where they are widely cultured. However, there is little information on the basic biology of this species. We evaluated the effect of temperature （16, 19, 22, 25, 28, 31, and 34℃） on the standard metabolic rates （SMRs） of juvenile and adult E. carinicauda in the laboratory under static conditions. The oxygen consumption rate （OCR）, ammonia-N excretion rate （AER）, and atornic ratio of oxygen consumed to nitrogen consumed （O：N ratio） of juvenile and adult E. carinicauda were significantly influenced by temperature （P〈0.05）. Both the OCR and AER of juveniles increased significantly with increasing temperature from 16 to 34℃, but the maximum OCR for adults was at 31℃. Juvenile shrimp exhibited a higher OCR than the adults from 19 to 34℃. There was no significant difference between the AERs of the two life-stages from 16 to 31 ℃ （P〉0.05）. The O：N ratio in juveniles was significantly higher than that in the adults over the entire temperature range （P〈0.05）. The temperature coefficient （Q_10） of OCR and AER ranged from 5.03 to 0.86 and 6,30 to 0.85 for the adults, respectively, and from 6,09-1.03 and 3.66-1.80 for the juveniles, respectively. The optimal temperature range for growth of the juvenile and adult shrimp was from 28 to 31℃, based on Q_10 and SMR values. Results from the present study may be used to guide pond culture production ofE. carinicauda.展开更多
Denitrification-induced nitrogen(N) losses from croplands may be greatly increased by intensive fertilization.However,the accurate quantification of these losses is still challenging due to insufficient available in s...Denitrification-induced nitrogen(N) losses from croplands may be greatly increased by intensive fertilization.However,the accurate quantification of these losses is still challenging due to insufficient available in situ measurements of soil dinitrogen(N) emissions.We carried out two one-week experiments in a maize-wheat cropping system with calcareous soil using theN gas-flux(NGF) method to measure in situ Nfluxes following urea application.Applications ofN-labeled urea(99 atom%,130-150 kg N ha) were followed by irrigation on the 1 st,3 rd,and 5 th days after fertilization(DAF 1,3,and 5,respectively).The detection limits of the soil Nfluxes were 163-1 565,81-485,and 54-281 μg N mhfor the two-,four-,and six-hour static chamber enclosures,respectively.The Nfluxes measured in 120 cases varied between 159 and 2 943(811 on average) μg N mh.which were higher than the detection limits,with the exception of only two cases.The Nfluxes at DAF 3 were significantly higher(by nearly 80%(P<0.01)) than those at DAF 1 and 5 in the maize experiment,while there were no significant differences among the irrigation times in the wheat experiment.The Nfluxes and the ratios of nitrous oxide(NO) to the NO plus Nfluxes following urea application to maize were approximately 65% and 11 times larger,respectively(P<0.01),than those following urea application to wheat.Such differences could be mainly attributed to the higher soil water contents,temperatures,and availability of soil N substrates in the maize experiment than in the wheat experiment.This study suggests that theNGF method is sensitive enough to measure in situ Nfluxes from intensively fertilized croplands with calcareous soils.展开更多
Tropical peat swamp forest beds that have been reclaimed for agricultural use are generally an active source of nitrous oxide （N2O） efflux, however, the mechanism by which reclaimed tropical peat soils promote the e...Tropical peat swamp forest beds that have been reclaimed for agricultural use are generally an active source of nitrous oxide （N2O） efflux, however, the mechanism by which reclaimed tropical peat soils promote the emergence of N2O emitters in soil microbial communities remains unclear. The purpose of this study was to reveal the vertical distribution of N2O emission potential and its correlation with mineral nitrogen contents in reclaimed soils. Using a culture-based N2O emission assay, the N2O emission potentials of soil at various depths （0-450 cm） were investigated in two oil palm plantations in Sarawak, Malaysia, which had elapsed times of two years （E2Y） and 10 years （El 0Y） after deforestation, respectively. On the basis of the relationship between the vertical profiles of N2O emission potentials and the contents of mineralized nitrogen in the peat soils at various depths, the impact of land management on soil microbial communities was discussed. The peat soil at plantation site E2Y showed a trend of high N2O production in deep layers （200-400 cm）, whereas the older plantation site E10Y showed considerably more active N2O emission in shallow soil （10-50 cm）. N2O emission potentials among the soil microbial communities at different soil depths at the E10Y site showed positive correlations with NO3- and NH4＋ contents, whereas, soils obtained from the E2Y site had N2O emission potentials that were inversely proportional to the contents of NO3-. This contrasting vertical correlation between N2O-emitting potentials and mineralized nitrogen contents in bulk soils suggests that active N2O emission in deep soil at the E2Y site has maintained the original carbon-nitrogen （C/N） ratio of the peat soil, whereas at EIOY, such a regulatory system has been lost due to advanced soil degradation, leading to dynamic changes in the nitrogen cycle in shallow soil.展开更多
基金Supported by the National Key Technology Research and Development Program of China(No.2011BAD13B01)the National Natural Science Foundation of China(General Program)(No.41376165)the China Agriculture Research System CARS-47
文摘Ridgetail white prawn （Exopalaemon carinicauda） are of significant economic importance in China where they are widely cultured. However, there is little information on the basic biology of this species. We evaluated the effect of temperature （16, 19, 22, 25, 28, 31, and 34℃） on the standard metabolic rates （SMRs） of juvenile and adult E. carinicauda in the laboratory under static conditions. The oxygen consumption rate （OCR）, ammonia-N excretion rate （AER）, and atornic ratio of oxygen consumed to nitrogen consumed （O：N ratio） of juvenile and adult E. carinicauda were significantly influenced by temperature （P〈0.05）. Both the OCR and AER of juveniles increased significantly with increasing temperature from 16 to 34℃, but the maximum OCR for adults was at 31℃. Juvenile shrimp exhibited a higher OCR than the adults from 19 to 34℃. There was no significant difference between the AERs of the two life-stages from 16 to 31 ℃ （P〉0.05）. The O：N ratio in juveniles was significantly higher than that in the adults over the entire temperature range （P〈0.05）. The temperature coefficient （Q_10） of OCR and AER ranged from 5.03 to 0.86 and 6,30 to 0.85 for the adults, respectively, and from 6,09-1.03 and 3.66-1.80 for the juveniles, respectively. The optimal temperature range for growth of the juvenile and adult shrimp was from 28 to 31℃, based on Q_10 and SMR values. Results from the present study may be used to guide pond culture production ofE. carinicauda.
基金jointly supported by the National Natural Science Foundation of China(41877333,41830751 and 41761144054)the Basic Research Program of Frontier Sciences of Chinese Academy of Sciences(ZDBSLY-DQCOO7)the National Key Research and Development Program of China(2017YFD0200100)。
文摘Denitrification-induced nitrogen(N) losses from croplands may be greatly increased by intensive fertilization.However,the accurate quantification of these losses is still challenging due to insufficient available in situ measurements of soil dinitrogen(N) emissions.We carried out two one-week experiments in a maize-wheat cropping system with calcareous soil using theN gas-flux(NGF) method to measure in situ Nfluxes following urea application.Applications ofN-labeled urea(99 atom%,130-150 kg N ha) were followed by irrigation on the 1 st,3 rd,and 5 th days after fertilization(DAF 1,3,and 5,respectively).The detection limits of the soil Nfluxes were 163-1 565,81-485,and 54-281 μg N mhfor the two-,four-,and six-hour static chamber enclosures,respectively.The Nfluxes measured in 120 cases varied between 159 and 2 943(811 on average) μg N mh.which were higher than the detection limits,with the exception of only two cases.The Nfluxes at DAF 3 were significantly higher(by nearly 80%(P<0.01)) than those at DAF 1 and 5 in the maize experiment,while there were no significant differences among the irrigation times in the wheat experiment.The Nfluxes and the ratios of nitrous oxide(NO) to the NO plus Nfluxes following urea application to maize were approximately 65% and 11 times larger,respectively(P<0.01),than those following urea application to wheat.Such differences could be mainly attributed to the higher soil water contents,temperatures,and availability of soil N substrates in the maize experiment than in the wheat experiment.This study suggests that theNGF method is sensitive enough to measure in situ Nfluxes from intensively fertilized croplands with calcareous soils.
文摘Tropical peat swamp forest beds that have been reclaimed for agricultural use are generally an active source of nitrous oxide （N2O） efflux, however, the mechanism by which reclaimed tropical peat soils promote the emergence of N2O emitters in soil microbial communities remains unclear. The purpose of this study was to reveal the vertical distribution of N2O emission potential and its correlation with mineral nitrogen contents in reclaimed soils. Using a culture-based N2O emission assay, the N2O emission potentials of soil at various depths （0-450 cm） were investigated in two oil palm plantations in Sarawak, Malaysia, which had elapsed times of two years （E2Y） and 10 years （El 0Y） after deforestation, respectively. On the basis of the relationship between the vertical profiles of N2O emission potentials and the contents of mineralized nitrogen in the peat soils at various depths, the impact of land management on soil microbial communities was discussed. The peat soil at plantation site E2Y showed a trend of high N2O production in deep layers （200-400 cm）, whereas the older plantation site E10Y showed considerably more active N2O emission in shallow soil （10-50 cm）. N2O emission potentials among the soil microbial communities at different soil depths at the E10Y site showed positive correlations with NO3- and NH4＋ contents, whereas, soils obtained from the E2Y site had N2O emission potentials that were inversely proportional to the contents of NO3-. This contrasting vertical correlation between N2O-emitting potentials and mineralized nitrogen contents in bulk soils suggests that active N2O emission in deep soil at the E2Y site has maintained the original carbon-nitrogen （C/N） ratio of the peat soil, whereas at EIOY, such a regulatory system has been lost due to advanced soil degradation, leading to dynamic changes in the nitrogen cycle in shallow soil.
