The effects of complex microorganisms in composting process of the municipal solid waste (MSW) and sludge were examined through inspecting biomass, temperature, oxygen consumption, organic mater, and C/N (the ratio of...The effects of complex microorganisms in composting process of the municipal solid waste (MSW) and sludge were examined through inspecting biomass, temperature, oxygen consumption, organic mater, and C/N (the ratio of carbon and nitrogen). The experimental results shows: complex microorganisms are effective to compose organic matter and speedup composting change into humus.展开更多
On the basis of the measurement of 210Pbex and 137Cs activities in the sediment cores taken from the intertidal zone on the west coast of the Bohai Gulf, the average sedimentation rates of modern sediments are calcula...On the basis of the measurement of 210Pbex and 137Cs activities in the sediment cores taken from the intertidal zone on the west coast of the Bohai Gulf, the average sedimentation rates of modern sediments are calculated. The results indicate that in the sandy area of the intertidal zone (from Daogouzi to the Duliujian River), the sedimentation rate from 1955 to 1963 is 3.43-4.06 cm/a, and is within the range of 0.65￣1.59 cm/a since 1963. The average sedimentation rate in the muddy area (around Qikou) is approximately 1.81 cm/a. The results above suggest that the sandy area of the intertidal zone has experienced rapid sedimentation from the 1950s to the 1960s, and the sedimentation slows down after the 1960s, and the sedimentation rates increase from north to south spatially. The rapid sedi- mentation from the 1950s to the 1960s in the sandy area is due to the fact that North China has plentiful precipitation during this period and the intertidal zone is supplied with abundant matter sources for sedimentation. After the 1960s, the weakened sedimentation may be a result of the reduction of sand transported to the intertidal zone, which is a consequence of diminished rainfall in North China and intensive human activities in the Haihe basin.展开更多
Using field experimental data of 17 yr of mowing succession of Leymus chinensis (Trin.) Tzvel. steppe of Inner Mongolia (Nei Mongol), we analyzed the dynamics of community composition based on plant functional groups ...Using field experimental data of 17 yr of mowing succession of Leymus chinensis (Trin.) Tzvel. steppe of Inner Mongolia (Nei Mongol), we analyzed the dynamics of community composition based on plant functional groups (PFGs), explored the relationship between changes of the PFGs proportion in community and the community annual net primary production (ANPP), and examined the influences of structural parameters on functional parameters. Our results showed that during 17 yr of mowing succession, changes in both community structure and function took place. The roles of different PFGs varied appar-ently with mowing succession: the dominance of rhizome grasses was replaced successively by annuals and biennials, tall bunch grasses, and short bunch grasses. Following 17 yr of mowing, the community became codominated by rhizome grasses, tall bunch grass, and short bunch grass. ANPP correlated significantly with annual precipitation in control plot, but not in successive mowing plot. Annual precipita-tion explained more than 62% of the annual variability in ANPP of control plot, whereas annual variation of ANPP in mowing plot was mainly driven by successive mowing disturbance. The community ANPP showed resilience to mowing disturbance and kept relatively stable initially through internal regulation of PFGs, and declined to a lower level with structural changes of the community after about 5 yr, and then again maintained at a stable level through structural regulation. Therefore, in mowing succession the commu-nity structurere presented by PFGs changed gradually while the community function represented by ANPP declined abruptly. The community relied on constantly regulating the structure to maintain the function stability. The community function would degrade after its structure changed to certain degree.展开更多
For preventing ecosystem degradation, protecting natural habitats and conserving biodiversity within the habitats, 2588 nature reserves have been established in China at the end of 2010. The total area is up to 149.44...For preventing ecosystem degradation, protecting natural habitats and conserving biodiversity within the habitats, 2588 nature reserves have been established in China at the end of 2010. The total area is up to 149.44 million ha and covers over 15% of Chinese terrestrial surface. Land-cover change, as the primary driver of biodiversity change, directly impacts ecosystem structures and functions. In this paper, 180 National Nature Reserves （NNRs） are selected and their total area is 44.71 million ha, accounting for 29.9% of all NNRs in China. In terms of the ecosystem characteristics and their major protected object, all selected NNRs are classified into 7 types. A Positive and Negative Change Index of Land-cover （PNCIL） was developed to analyze the land-cover change of each NNRs type from the late 1980s to 2005. The results show that the land-cover of all selected NNRs types have degradated to a certain degree except the forest ecosystem reserves with a decreasing rate, but the rate of degrada tion alleviated gradually. The mean positive and negative change rates of land-cover in all core zones decreased by 0.69% and 0.16% respectively. The landscape pattern of land-cover in the core zones was more stable than that in the buffer zones and the experimental zones. Furthermore, the ecological diversity and patch connectivity of land-cover in selected NNRs increased generally. In short, the land-cover of 180 selected NNRs in China had a beneficial chan qe trend after NNRs established, especially between 1995 and 2005.展开更多
Dissolved oxygen (DO) concentrations were surveyed in the Daliao River Estuary in autumn to investigate the temporal and spatial trends of DO distributions. The results indicate that DO is weakly stratified in the Yin...Dissolved oxygen (DO) concentrations were surveyed in the Daliao River Estuary in autumn to investigate the temporal and spatial trends of DO distributions. The results indicate that DO is weakly stratified in the Yingkou section of the Daliao River Estuary, and remains constant vertically in the areas near and out of the entrance. Horizontally, both instantaneous and continuous observations show that the Yingkou section of the Daliao River Estuary is affected by hypoxic conditions; while no conditions of low DO have been observed in the areas near and out of the entrance. DO-salinity correlations exhibit different controlling factors of DO distributions in different sections of the Daliao River Estuary. At the upstream part of the Yingkou section of the Daliao River (A1-A4), oxygen demanding materials and the associated biochemical processes are the main factor controlling the DO distribution, but in the lower part of the Yingkou section and the area near and out of the entrance (A5-A15), tidal advections are more influential for DO distributions.展开更多
Bio-surfactant is a new type of surfactant that is produced in microbial metabolism. Adding bio-surfactant during composting process, especially to those contain some toxic substances, has been proved to be a promisin...Bio-surfactant is a new type of surfactant that is produced in microbial metabolism. Adding bio-surfactant during composting process, especially to those contain some toxic substances, has been proved to be a promising way. In this study, Strains Ⅲ(2), a bacterial with high activity to produce bio-surfactant, were isolated firstly. Following comparison experiments with and without adding Strains Ⅲ(2), namely Run 1 and Run R, were conducted, respectively. The experimental results showed that, by adding Strains Ⅲ(2), the surface tension could reduce from 46.5 mN/m to 39.8 mN/m and the corresponding time to maintain the surface tension under 50 mN/m could prolong from 60 h to 90 h. The oxygen uptake rate and total accumulated oxygen consumption with Stains Ⅲ(2) were both higher than those without Strains Ⅲ(2), while the accumulation of H_2S in outlet gas was reduced to around 50% of Run R. Moreover, two additional experiments were also carried out to examine the effects of strains coming from different systems. One is adding Strains Ⅲ(2) with a dose of 0.4%(Run 2), and the other is seedling commercial Strains at the same conditions, the composting experiments showed that: Run 2 was more effective than Run 3, because the commercial Strains can be suppressed significantly in a complex composting system with different pH, high temperature and some of metals. The bio-surfactant was also added into the solid waste, which contained some toxic substances, the corresponding results showed that the remove rate of Hg and sodium pentachlorophenolate(PCP-Na) could be improved highly. Thus, the microenvironment, reactionrate and composting quality could be enhanced effectively by adding bio-surfactant to the composting process.展开更多
Dispersion of a solid particle in water may lead to the formation of hydration film on the particle surface, which can strongly increase the repulsive force between the particles and thus strongly affect the stability...Dispersion of a solid particle in water may lead to the formation of hydration film on the particle surface, which can strongly increase the repulsive force between the particles and thus strongly affect the stability of dispersions. The hydration film thickness, which varies with the variation of property of suspension particles, is one of the most impor- tant parameters of hydration film, and is also one of the most difficult parameters that can be measured accurately. In this paper, a method, based on force-distance curve of atomic force microscopy, for determining the hydration film thick- ness of particles is developed. The method utilizes the differ- ence of cantilever deflection before, between and after pene- trating the hydration films between tip and sample, which reflect the difference of slope on the force-distance curve. 3 samples, mica, glass and stainless steel, were used for hydra- tion thickness determination, and the results show that the hydration film thickness between silicon tip and mica, glass and stainless steel are 30.0±2.0, 29.0±1.0 and 32.5±2.5 nm, respectively.展开更多
文摘The effects of complex microorganisms in composting process of the municipal solid waste (MSW) and sludge were examined through inspecting biomass, temperature, oxygen consumption, organic mater, and C/N (the ratio of carbon and nitrogen). The experimental results shows: complex microorganisms are effective to compose organic matter and speedup composting change into humus.
基金financed by the Hi-tech Research and Development Program of China(“863”Program)under contract No.2002AA648010
文摘On the basis of the measurement of 210Pbex and 137Cs activities in the sediment cores taken from the intertidal zone on the west coast of the Bohai Gulf, the average sedimentation rates of modern sediments are calculated. The results indicate that in the sandy area of the intertidal zone (from Daogouzi to the Duliujian River), the sedimentation rate from 1955 to 1963 is 3.43-4.06 cm/a, and is within the range of 0.65￣1.59 cm/a since 1963. The average sedimentation rate in the muddy area (around Qikou) is approximately 1.81 cm/a. The results above suggest that the sandy area of the intertidal zone has experienced rapid sedimentation from the 1950s to the 1960s, and the sedimentation slows down after the 1960s, and the sedimentation rates increase from north to south spatially. The rapid sedi- mentation from the 1950s to the 1960s in the sandy area is due to the fact that North China has plentiful precipitation during this period and the intertidal zone is supplied with abundant matter sources for sedimentation. After the 1960s, the weakened sedimentation may be a result of the reduction of sand transported to the intertidal zone, which is a consequence of diminished rainfall in North China and intensive human activities in the Haihe basin.
文摘Using field experimental data of 17 yr of mowing succession of Leymus chinensis (Trin.) Tzvel. steppe of Inner Mongolia (Nei Mongol), we analyzed the dynamics of community composition based on plant functional groups (PFGs), explored the relationship between changes of the PFGs proportion in community and the community annual net primary production (ANPP), and examined the influences of structural parameters on functional parameters. Our results showed that during 17 yr of mowing succession, changes in both community structure and function took place. The roles of different PFGs varied appar-ently with mowing succession: the dominance of rhizome grasses was replaced successively by annuals and biennials, tall bunch grasses, and short bunch grasses. Following 17 yr of mowing, the community became codominated by rhizome grasses, tall bunch grass, and short bunch grass. ANPP correlated significantly with annual precipitation in control plot, but not in successive mowing plot. Annual precipita-tion explained more than 62% of the annual variability in ANPP of control plot, whereas annual variation of ANPP in mowing plot was mainly driven by successive mowing disturbance. The community ANPP showed resilience to mowing disturbance and kept relatively stable initially through internal regulation of PFGs, and declined to a lower level with structural changes of the community after about 5 yr, and then again maintained at a stable level through structural regulation. Therefore, in mowing succession the commu-nity structurere presented by PFGs changed gradually while the community function represented by ANPP declined abruptly. The community relied on constantly regulating the structure to maintain the function stability. The community function would degrade after its structure changed to certain degree.
基金National Natural Science Foundation of China, No.41271406 No.40801150+3 种基金 China National Science Fund for Distinguished Young Scholars, No.40825003 National Basic Research Program of China, No.2009CB421105 No.2010CB95090403 Youth Science Funds of State Key Laboratory of Resources and Environment Information System, CAS
文摘For preventing ecosystem degradation, protecting natural habitats and conserving biodiversity within the habitats, 2588 nature reserves have been established in China at the end of 2010. The total area is up to 149.44 million ha and covers over 15% of Chinese terrestrial surface. Land-cover change, as the primary driver of biodiversity change, directly impacts ecosystem structures and functions. In this paper, 180 National Nature Reserves （NNRs） are selected and their total area is 44.71 million ha, accounting for 29.9% of all NNRs in China. In terms of the ecosystem characteristics and their major protected object, all selected NNRs are classified into 7 types. A Positive and Negative Change Index of Land-cover （PNCIL） was developed to analyze the land-cover change of each NNRs type from the late 1980s to 2005. The results show that the land-cover of all selected NNRs types have degradated to a certain degree except the forest ecosystem reserves with a decreasing rate, but the rate of degrada tion alleviated gradually. The mean positive and negative change rates of land-cover in all core zones decreased by 0.69% and 0.16% respectively. The landscape pattern of land-cover in the core zones was more stable than that in the buffer zones and the experimental zones. Furthermore, the ecological diversity and patch connectivity of land-cover in selected NNRs increased generally. In short, the land-cover of 180 selected NNRs in China had a beneficial chan qe trend after NNRs established, especially between 1995 and 2005.
基金the National Basic Research Priorities Program of China under contract No.2001CCA01900.
文摘Dissolved oxygen (DO) concentrations were surveyed in the Daliao River Estuary in autumn to investigate the temporal and spatial trends of DO distributions. The results indicate that DO is weakly stratified in the Yingkou section of the Daliao River Estuary, and remains constant vertically in the areas near and out of the entrance. Horizontally, both instantaneous and continuous observations show that the Yingkou section of the Daliao River Estuary is affected by hypoxic conditions; while no conditions of low DO have been observed in the areas near and out of the entrance. DO-salinity correlations exhibit different controlling factors of DO distributions in different sections of the Daliao River Estuary. At the upstream part of the Yingkou section of the Daliao River (A1-A4), oxygen demanding materials and the associated biochemical processes are the main factor controlling the DO distribution, but in the lower part of the Yingkou section and the area near and out of the entrance (A5-A15), tidal advections are more influential for DO distributions.
基金Foundation item: The National Basic Research Program(973) of China(No. 2002CB410800 7 2002CB412302) and the National Hi Tech Research and DevelopmentProgram(863) of China(No. 2002AA601012)
文摘Bio-surfactant is a new type of surfactant that is produced in microbial metabolism. Adding bio-surfactant during composting process, especially to those contain some toxic substances, has been proved to be a promising way. In this study, Strains Ⅲ(2), a bacterial with high activity to produce bio-surfactant, were isolated firstly. Following comparison experiments with and without adding Strains Ⅲ(2), namely Run 1 and Run R, were conducted, respectively. The experimental results showed that, by adding Strains Ⅲ(2), the surface tension could reduce from 46.5 mN/m to 39.8 mN/m and the corresponding time to maintain the surface tension under 50 mN/m could prolong from 60 h to 90 h. The oxygen uptake rate and total accumulated oxygen consumption with Stains Ⅲ(2) were both higher than those without Strains Ⅲ(2), while the accumulation of H_2S in outlet gas was reduced to around 50% of Run R. Moreover, two additional experiments were also carried out to examine the effects of strains coming from different systems. One is adding Strains Ⅲ(2) with a dose of 0.4%(Run 2), and the other is seedling commercial Strains at the same conditions, the composting experiments showed that: Run 2 was more effective than Run 3, because the commercial Strains can be suppressed significantly in a complex composting system with different pH, high temperature and some of metals. The bio-surfactant was also added into the solid waste, which contained some toxic substances, the corresponding results showed that the remove rate of Hg and sodium pentachlorophenolate(PCP-Na) could be improved highly. Thus, the microenvironment, reactionrate and composting quality could be enhanced effectively by adding bio-surfactant to the composting process.
文摘Dispersion of a solid particle in water may lead to the formation of hydration film on the particle surface, which can strongly increase the repulsive force between the particles and thus strongly affect the stability of dispersions. The hydration film thickness, which varies with the variation of property of suspension particles, is one of the most impor- tant parameters of hydration film, and is also one of the most difficult parameters that can be measured accurately. In this paper, a method, based on force-distance curve of atomic force microscopy, for determining the hydration film thick- ness of particles is developed. The method utilizes the differ- ence of cantilever deflection before, between and after pene- trating the hydration films between tip and sample, which reflect the difference of slope on the force-distance curve. 3 samples, mica, glass and stainless steel, were used for hydra- tion thickness determination, and the results show that the hydration film thickness between silicon tip and mica, glass and stainless steel are 30.0±2.0, 29.0±1.0 and 32.5±2.5 nm, respectively.
