A cold vent is an area where methane-rich fluid seepage occurs. This seepage may alter the local temperature, salinity, and subsequent accumulation of the gas hydrate. Using a kinetic gas hydrate formation model and i...A cold vent is an area where methane-rich fluid seepage occurs. This seepage may alter the local temperature, salinity, and subsequent accumulation of the gas hydrate. Using a kinetic gas hydrate formation model and in situ measurement of tempera- ture, salinity and fluid flux at the southern summit of Hydrate Ridge, we simuIate the gas hydrate accumulation at three distinct fluid sites： clam, bacterial mat, and gas discharge sites. At the clam sites （pore water flux 〈 20 kg m-2 yr-1）, pore water advec- tion has little influence on temperature and salinity. However, the salinity and temperature are increased （peak salinity 〉 0.8 tool kg-1） by the formation of gas hydrate causing the base of the hydrate stability zone to move gradually from -115 to -70 meters below seafloor （mbsf）. The gas hydrate saturation at the clam sites is relatively high. The water flux at the bacterial mat sites ranges from 100 to 2500 kg m-2 yr-1. The water flow suppresses the increase in salinity resulting in a salinity close to or slightly higher than that of seawater （〈 0.65 mol kg-l）. Heat advection by water flow increases temperature significantly, shifting the base of the hydrate stability zone to above 50 or even 3 mbsf. The gas hydrate saturation is relatively low at the bacterial mat site. At the gas discharge sites, the pore water flux could reach 10^10 kg m-2 yr-1, and the temperature could reach that of the source area in 9 min. There is no gas hydrate formation at the gas discharge sites. Our simulative analysis therefore reveals that a lower pore water flux would result in lower salinity, higher temperature, and a shallower base of the hydrate sta- bility zone. This in turn induces a lower gas hydrate formation rate, lower hydrate saturation, and eventually less gas hydrate resources.展开更多
The Deep-towed Acoustics and Geophysics System (DTAGS) is a high frequency (220-820 Hz) multichannel seismic system towed about 300 m above seafloor.Compared to the conventional surface-towed seismic system,the DTAGS ...The Deep-towed Acoustics and Geophysics System (DTAGS) is a high frequency (220-820 Hz) multichannel seismic system towed about 300 m above seafloor.Compared to the conventional surface-towed seismic system,the DTAGS system is characterized by its shorter wavelength (<6 m),smaller Fresnel zone,and greater sampling in wavenumber space,so it has unique advantages in distinguishing fine sedimentary layers and geological structures.Given the near-bottom configuration and wide high-frequency bandwidth,the precise source and hydrophone positioning is the basement of subsequent seismic imaging and velocity analysis,and thus the quality of array geometry inversion is the key of DTAGS data processing.In the application of exploration for marine gas hydrate on mid-slope of northern Cascadia margin,the DTAGS system has shown high vertical and lateral resolution images of the sedimentary and structural features of the Cucumber Ridge (a carbonate mound) and Bullseye Vent (a cold vent),and provided abundant information for the evaluation of gas hydrate concentration and the mechanism of fluid flow that controls the formation and distribution of gas hydrate.展开更多
Coloration is an important phenotypic trait for multiple adaptive functions.It is interesting to fi nd white-eye(AW)and orange-eye(AO)phenotypes in the shrimp Alvinocaris longirostris inhabiting the deep-sea cold seep...Coloration is an important phenotypic trait for multiple adaptive functions.It is interesting to fi nd white-eye(AW)and orange-eye(AO)phenotypes in the shrimp Alvinocaris longirostris inhabiting the deep-sea cold seep and hydrothermal vent areas of the northwestern Pacifi c.By comparative transcriptome analyses,1491 diff erentially expressed genes(DEGs)were identified between AW and AO.Among them,many DEGs were associated with immunity,antioxidation,and detoxifi cation.Two signifi cant enzyme encoding genes,xanthine dehydrogenase,and tryptophan oxidase involved in pigment biosynthesis pathways were up-regulated in AW and AO,respectively,which might be related to the diff erences of white and orange eye phenotypes.Moreover,single nucleotide polymorphism(SNP)calling detected that genotypes of 28 SNP distributing in 14 unigenes were completely diff erent between AW and AO.Particularly,there were three and two non-synonymous mutations in immune genes crustin Pm5 and antimicrobial peptide,respectively.Results indicate that the diff erence in eye color is probably resulted from immune response to variable micro-environmental stressors encountered in the dispersal process of the shrimps,such as symbiotic microbes,pathogens,and toxic substances,and might be genetically fi xed at last.The suggested pathway preliminarily explained the formation mechanism of diff erent eye phenotypes in Alvinocaridid shrimps,providing a basis for further study on adaptive evolution of eyes in deep-sea chemosynthetic faunas.展开更多
南海东沙东北部碳酸盐岩和泥质沉积物中的生物标志化合物组合及其碳同位素组成分析表明,研究区内甲烷缺氧氧化作用(anaerobic oxidation of methane-AOM)发育。研究区内碳酸盐岩中含丰富的AOM标志化合物,2,6,11,15-四甲基十六烷(Croceta...南海东沙东北部碳酸盐岩和泥质沉积物中的生物标志化合物组合及其碳同位素组成分析表明,研究区内甲烷缺氧氧化作用(anaerobic oxidation of methane-AOM)发育。研究区内碳酸盐岩中含丰富的AOM标志化合物,2,6,11,15-四甲基十六烷(Crocetane-Cr.)、2,6,10,15,19-五甲基番茄烷(Pentamethylicosane-PMI)和2,6,10,15,19,23-六甲基二十四烷(Squalane-Sq角鲨烷)的13C亏损强烈(δ13C值介于-74.2‰^-119.0‰PDB之间),表明碳酸盐岩形成于AOM,同时反映该研究区曾发生过强烈、持续的富CH4流体释放活动。柱状泥质沉积物中,AOM生物标志化合物在硫酸岩-甲烷过渡带(SMI—Sulfate-Methane Interface)边界附近相对丰度高,SMI之上样品中含量低,或未检出,表明现代环境在SMI附近有大量嗜甲烷微生物生长,使得深部上升的甲烷被大量消耗,很少有甲烷逸出海底。AOM生物标志化合物可用来指示SMI边界。不同站位、不同岩性AOM生物标志化合物组成(包括碳同位素组成)的差异反映了嗜甲烷古细菌组成的不同。展开更多
This paper aims at solving the problems of low thermal collection rate,inconvenient maintenance,hindering indoor using during the application of passive solar technologies in rural houses in severe cold region.All the...This paper aims at solving the problems of low thermal collection rate,inconvenient maintenance,hindering indoor using during the application of passive solar technologies in rural houses in severe cold region.All these defects prevent the passive solar houses' further development. This paper chooses trombe wall,which has higher thermal efficiency of the passive solar house,as research object. The traditional vent is improved into a new type of ventilation device. This improvement overcomes the shortcoming,which traditional vent loses huge heat,and simplifies the construction of vent. Comparing with traditional trombe wall,the energy saving rate is 15. 69%.展开更多
基金supported by National Basic Research Program of China (Grant No.2009CB219508)Chinese Academy of Sciences (Grant No.KZCX2-YW-GJ03)+2 种基金National Natural Science Foundation of China (GrantNos. 91228206 & 40725011)GIGCAS 135 Program (Grant No.Y234021001)Scientific and Technological Program of Guangdong Province (Grant No. 2011A080403021)
文摘A cold vent is an area where methane-rich fluid seepage occurs. This seepage may alter the local temperature, salinity, and subsequent accumulation of the gas hydrate. Using a kinetic gas hydrate formation model and in situ measurement of tempera- ture, salinity and fluid flux at the southern summit of Hydrate Ridge, we simuIate the gas hydrate accumulation at three distinct fluid sites： clam, bacterial mat, and gas discharge sites. At the clam sites （pore water flux 〈 20 kg m-2 yr-1）, pore water advec- tion has little influence on temperature and salinity. However, the salinity and temperature are increased （peak salinity 〉 0.8 tool kg-1） by the formation of gas hydrate causing the base of the hydrate stability zone to move gradually from -115 to -70 meters below seafloor （mbsf）. The gas hydrate saturation at the clam sites is relatively high. The water flux at the bacterial mat sites ranges from 100 to 2500 kg m-2 yr-1. The water flow suppresses the increase in salinity resulting in a salinity close to or slightly higher than that of seawater （〈 0.65 mol kg-l）. Heat advection by water flow increases temperature significantly, shifting the base of the hydrate stability zone to above 50 or even 3 mbsf. The gas hydrate saturation is relatively low at the bacterial mat site. At the gas discharge sites, the pore water flux could reach 10^10 kg m-2 yr-1, and the temperature could reach that of the source area in 9 min. There is no gas hydrate formation at the gas discharge sites. Our simulative analysis therefore reveals that a lower pore water flux would result in lower salinity, higher temperature, and a shallower base of the hydrate sta- bility zone. This in turn induces a lower gas hydrate formation rate, lower hydrate saturation, and eventually less gas hydrate resources.
基金supported by National Natural Science Foundation of China (Grant Nos. 40830423 and 40904029)Scientific Research Foundation for the Returned Overseas Chinese Scholars,Ministry of Education of China
文摘The Deep-towed Acoustics and Geophysics System (DTAGS) is a high frequency (220-820 Hz) multichannel seismic system towed about 300 m above seafloor.Compared to the conventional surface-towed seismic system,the DTAGS system is characterized by its shorter wavelength (<6 m),smaller Fresnel zone,and greater sampling in wavenumber space,so it has unique advantages in distinguishing fine sedimentary layers and geological structures.Given the near-bottom configuration and wide high-frequency bandwidth,the precise source and hydrophone positioning is the basement of subsequent seismic imaging and velocity analysis,and thus the quality of array geometry inversion is the key of DTAGS data processing.In the application of exploration for marine gas hydrate on mid-slope of northern Cascadia margin,the DTAGS system has shown high vertical and lateral resolution images of the sedimentary and structural features of the Cucumber Ridge (a carbonate mound) and Bullseye Vent (a cold vent),and provided abundant information for the evaluation of gas hydrate concentration and the mechanism of fluid flow that controls the formation and distribution of gas hydrate.
基金Supported by the National Key R&D Program of China(No.2018YFC0310802)the National Natural Science Foundation of China(No.31872215)+2 种基金the Senior User Project of R/V Kexue(No.KEXUE2019GZ02)the Strategic Priority Research Program of the Chinese Academy of Sciences(CAS)(No.XDA22050302)the Key Research Program of Frontier Sciences,CAS(No.QYZDB-SSW-DQC036)。
文摘Coloration is an important phenotypic trait for multiple adaptive functions.It is interesting to fi nd white-eye(AW)and orange-eye(AO)phenotypes in the shrimp Alvinocaris longirostris inhabiting the deep-sea cold seep and hydrothermal vent areas of the northwestern Pacifi c.By comparative transcriptome analyses,1491 diff erentially expressed genes(DEGs)were identified between AW and AO.Among them,many DEGs were associated with immunity,antioxidation,and detoxifi cation.Two signifi cant enzyme encoding genes,xanthine dehydrogenase,and tryptophan oxidase involved in pigment biosynthesis pathways were up-regulated in AW and AO,respectively,which might be related to the diff erences of white and orange eye phenotypes.Moreover,single nucleotide polymorphism(SNP)calling detected that genotypes of 28 SNP distributing in 14 unigenes were completely diff erent between AW and AO.Particularly,there were three and two non-synonymous mutations in immune genes crustin Pm5 and antimicrobial peptide,respectively.Results indicate that the diff erence in eye color is probably resulted from immune response to variable micro-environmental stressors encountered in the dispersal process of the shrimps,such as symbiotic microbes,pathogens,and toxic substances,and might be genetically fi xed at last.The suggested pathway preliminarily explained the formation mechanism of diff erent eye phenotypes in Alvinocaridid shrimps,providing a basis for further study on adaptive evolution of eyes in deep-sea chemosynthetic faunas.
文摘南海东沙东北部碳酸盐岩和泥质沉积物中的生物标志化合物组合及其碳同位素组成分析表明,研究区内甲烷缺氧氧化作用(anaerobic oxidation of methane-AOM)发育。研究区内碳酸盐岩中含丰富的AOM标志化合物,2,6,11,15-四甲基十六烷(Crocetane-Cr.)、2,6,10,15,19-五甲基番茄烷(Pentamethylicosane-PMI)和2,6,10,15,19,23-六甲基二十四烷(Squalane-Sq角鲨烷)的13C亏损强烈(δ13C值介于-74.2‰^-119.0‰PDB之间),表明碳酸盐岩形成于AOM,同时反映该研究区曾发生过强烈、持续的富CH4流体释放活动。柱状泥质沉积物中,AOM生物标志化合物在硫酸岩-甲烷过渡带(SMI—Sulfate-Methane Interface)边界附近相对丰度高,SMI之上样品中含量低,或未检出,表明现代环境在SMI附近有大量嗜甲烷微生物生长,使得深部上升的甲烷被大量消耗,很少有甲烷逸出海底。AOM生物标志化合物可用来指示SMI边界。不同站位、不同岩性AOM生物标志化合物组成(包括碳同位素组成)的差异反映了嗜甲烷古细菌组成的不同。
基金Sponsored by the National Science-Technology Support Plan Projects (Grant No.2011BAJ08B06-2)
文摘This paper aims at solving the problems of low thermal collection rate,inconvenient maintenance,hindering indoor using during the application of passive solar technologies in rural houses in severe cold region.All these defects prevent the passive solar houses' further development. This paper chooses trombe wall,which has higher thermal efficiency of the passive solar house,as research object. The traditional vent is improved into a new type of ventilation device. This improvement overcomes the shortcoming,which traditional vent loses huge heat,and simplifies the construction of vent. Comparing with traditional trombe wall,the energy saving rate is 15. 69%.
