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911.
Shen Yu Miao Weilin Chen Wenqin Tao Wentan Dai Liandi Long Jinling Huang 《Chemical Speciation and Bioavailability》2017,29(1):97-109
Salinity levels and drought status of coastal wetlands may be strongly affected by climate change, and changes in the nitrogen cycle of mangrove wetlands may also be affected. We established combinations of three salinity and water levels with applied stable isotope 15N to study the δ15N distributions in the sediment and plants of a greenhouse-based simulated mangrove Aegiceras corniculatum wetland system. The stable isotope 13C and 15N, C and N contents and the C:N ratio were determined. Results showed that increasing in salinity significantly increased the δ13C value in plant organs. The δ15N value of plant organs increased with increasing water level in low salinity (10‰) and medium salinity (20‰) treatment groups but not in the high salinity (30‰) treatment group. This may attributed to A. corniculatum adjusting the δ15N distribution in different organs in response to high salinity stress. Compared to the δ13C, the δ15N values of plant were strongly affected by salinity and water level treatments, indicating that the behavior of N cycle was somewhat different than the C cycle, and affected by the combined effects of both salinity and water level. Most of 15N absorbed by plant tissues were in leaves except for the highest salinity and high water level treatment, showing at increasing water level, the proportion of 15N increased in root. Overall, the measured indicators exhibited different responses to salinity level and water level, suggesting that the changes in salinity and water levels have an impact on N cycling processes of wetland systems. 相似文献
912.
剩余污泥资源化利用新工艺研究进展 总被引:1,自引:0,他引:1
随着城市化进程加速, 污水处理厂剩余污泥大量产生, 如何对其进行处理并有效资源化利用成为广泛关注的问题。文章在综述我国城市污水处理厂剩余污泥特征、相应处理与综合利用方法的基础上, 进一步综述了污泥干化芦苇床、人工湿地、微生物燃料电池以及相关组合工艺等剩余污泥资源化利用新工艺。总结了各种新工艺的优势以及当前尚未解决的关键问题, 对未来新工艺的潜在应用进行了展望, 以期开发出低能耗、低成本、高效率、绿色生态的技术, 真正实现剩余污泥的减量化、无害化、稳定化和资源化。 相似文献
913.
Derong Xiao Kun Tian Hua Yuan Yuming Yang Ningyun Li Shouguo Xu 《Frontiers of Biology in China》2008,3(3):338-343
Using GPS technology and community research methods for plant communities, we investigated the distribution patterns of aquatic
plant communities in the high plateaus of the Napahai Wetlands, Yunnan, China, as well as the species changes of plant communities
compared with that of 24 years ago since 2005. We found that the types and numbers of aquatic plant communities have changed.
Some pollution-tolerant, nutrient-loving plant communities such as Scirpus tabernaemontani, Zizania caduciflora, Myriophyllum spicatum, and Azolla imbricata flourished, while the primary aquatic plant communities were reduced or even disappeared. The number of aquatic plant communities
were increased from nine to 12 with the addition of two new emergent plant communities and one new floating-leaved plant community.
The increase in emergent plant communities was significant. From east to west and from south to north, various types of plant
communities were continuously distributed, including floating-leaved plant communities, emergent plant communities and submerged
plant communities. The composition of the communities became more complicated and the number of accompanying species increased,
while the percentage ratio of dominant plant species declined. In 2005, the coverage of emergent plant communities was the
largest (528.42 hm2) followed by submerged plant communities (362.50 hm2) and the floating-leaf plant communities was the smallest (70.23 hm2). The variations in the distribution of aquatic plant communities in the Napahai Wetlands reflect the natural responses to
the change of the wetland ecological environment. This study indicates that human disturbances have led to an inward movement
of the wetland shoreline, a decrease in water quality and a reduction in wetland habitat.
__________
Translated from Acta Ecologica Sinica, 2006, 26(11): 3624–3630 [译自: 生态学报] 相似文献
914.
Baoshan Cui Xinsheng Zhao Zhifeng Yang Bin Chen Na Tang Xuejie Tan 《Frontiers of Biology in China》2008,3(2):194-202
We investigated and monitored a reed community in the fields. Data on the bio-ecological characteristics and β-diversity of reed communities in different environmental gradients (mainly based on water depth) of the Yellow River Delta
were collected through multianalysis, extremum analysis and β-diversity index analysis. In accordance with the square sum of deviations (Ward) cluster analysis, 10 sampling plots were
divided into six types with the dominant plants in different plots varying according to the change in environmental gradients.
The dominant plants in these plots varied from aquatic plants to xerophytes and salt tolerant plants as water depth decreased.
The average height and diameter of the reeds at breast level were significantly correlated with the average water depth. The
fitness curves of average density and coverage with average water depth were nonlinear. When the average water depth was 0.3
m, the average density and coverage of reeds reached the apex value, while the height and diameter of the reeds at breast
level increased with the water depth. There were obvious changes to the environmental gradient in the Yellow River Delta.
The transitional communities were also found to exist in the Yellow River Delta by β-diversity analysis. Vicarious species appeared with the change in water depth. The occurrence of substitute species is determined
by the function of common species between adjacent belts. The different functions of common species led to differences in
community structure and function and differences in dominant plants. The result reflects the variations of species present
in different habitats and directly reflects environmental heterogeneity. The values of β-diversity indices of adjacent plots were higher than those of nonadjacent plots. There are transition zones between the xerophytes
and aquatic plants in the Yellow River Delta. In an aquatic environment, the similarity of reed community is higher than that
of xeromorphic plants. The β-diversity index can reflect plant succession trends caused by the change in environmental gradients in the Yellow River Delta.
The β-diversity index reveals plant responses to changes in environmental gradient and is helpful in observing changes in patterns
of species diversity in relation to environmental gradient change and evolving trends in the future, which in turn plays a
prominent role when environmental water requirements of wetland are discussed.
__________
Translated from Acta Ecologica Sinica, 2006, 26(5): 1533–1541 [译自: 生态学报] 相似文献
915.
Using GPS technology and community research methods for plant communities,we investigated the distribution patterns of aquatic plant communities in the high plateaus of the Napahai Wetlands,Yunnan,China,as well as the species changes of plant communities compared with that of 24 years ago since 2005.We found that the types and numbers of aquatic plant communities have changed.Some pollution-tolerant,nutrient-loving plant communities such as Scirpus tabernaemontani,Zizania caduciflora,Myriophyllum spicatum,and Azolla imbricata flourished,while the primary aquatic plant com-munities were reduced or even disappeared.The number of aquatic plant communities were increased from nine to 12 with the addition of two new emergent plant com-munities and one new floating-leaved plant community.The increase in emergent plant communities was signifi-cant.From east to west and from south to north,various types of plant communities were continuously distributed,including floating-leaved plant communities,emergent plant communities and submerged plant communities.The composition of the communities became more com-plicated and the number of accompanying species increased,while the percentage ratio of dominant plant species declined.In 2005,the coverage of emergent plant communities was the largest (528.42 hm2) followed by submerged plant communities (362.50 hm2) and the float-ing-leaf plant communities was the smallest (70.23 hm2).The variations in the distribution of aquatic plant com-munities in the Napahai Wetlands reflect the natural responses to the change of the wetland ecological envir-onment.This study indicates that human disturbances have led to an inward movement of the wetland shoreline,a decrease in water quality and a reduction in wetland habitat. 相似文献
916.
A well-developed aerenchyma is a major characteristic of aquatic plants. However, because such tissues are also found in wetland
and terrestrial plants, it is not always possible to use their presence or absence to distinguish aquatic species. Whereas
patterns of aerenchyma in roots have been studied in detail, those of the shoots have not. We collected and tested 110 species
of various aquatic and wetland plants, including ferns (5), basal angiosperms (5), monocots (65), and eudicots (35). Three
common and two rare types of aerenchyma were observed in their roots (three schizogeny and two lysigeny), plus five types
of schizogeny in their shoots. We re-confirmed that, although a well-developed aerenchyma is more common in most organs of
aquatic plants than in wetland plants, this presence cannot be used as strict evidence for the aquatic quality of vascular
plants. Here, aerenchyma patterns were stable at the genus level, and the consistency of pattern was stronger in the roots
than in the shoots. Furthermore, significant trends were verified in several higher taxa, and those consistencies of patterns
partially coincided with their phylogeny. 相似文献
917.
As one of the important ecosystem services of wetlands, carbon sequestration potential of lakes and swamps in China were investigated. Significant differences were found among the carbon sequestration potential of various lakes, determined by natural conditions and human disturbance. In this study, swamps had a carbon sequestration potential of 4.90 TgC, much higher than lakes in China. Mangrove and coastal marsh have the highest carbon sediment rate among swamps. Carbon sequestration potential in returning farms to lakes and swamps was 30.26 and 0.22 GgC. … a?1, respectively. Under the ongoing national wetland conservation action plan in China, the carbon sequestration potential of wetland restoration was 6.57 GgC. … a?1. Protection and restoration measurements can improve carbon sequestration potential of wetlands. 相似文献
918.
An in vitro embryo culture protocol was developed for Scirpus acutus Muhl. A maximum of 85.6% of germination was obtained when isolated embryos were cultured in vitro, a result similar to those reported in the literature with traditional dormancy breaking treatments. In vitro seedling development was optimal in half-strength Murashige and Skoog (1962) liquid medium. An average of 3–4 shoots were produced from the initial seedlings. Clusters of plantlets were successfully acclimatized and transferred to soil. These results corroborate the findings of previous studies stating that seed dormancy in Scirpus is caused by the seed/fruit coats. In vitro embryo culture thus allows for the production of Scirpus acutus Muhl. seedlings that can be transferred to natural or artificial wetlands. 相似文献
919.
Physical and Functional Responses to Experimental Marsh Surface Elevation Manipulation in Coos Bay's South Slough 总被引:1,自引:1,他引:0
Dike material was used as fill to construct high, mid, and low intertidal elevations in a subsided marsh located in the South Slough National Estuarine Research Reserve, Oregon. Marsh surface elevation change (including fill consolidation and compression of the original marsh soils), vertical accretion, tidal channel development, emergent vegetation colonization, and fish use were monitored over 3 years. Significant marsh surface elevation loss was detected at all elevations, with fill consolidation accounting for 70% of the loss at the highest elevation. Vertical accretion averaged 0.19 cm/yr in the sparsely vegetated Kunz Marsh compared with 0.70 cm/yr at the densely vegetated reference sites. Tidal channel development was influenced as much by marsh surface gradient as by marsh surface elevation. Vegetation colonization was directly correlated with elevation, whereas density and species richness of fish was inversely correlated with elevation. Manipulating the marsh surface to mid‐marsh elevations favors rapid vegetation colonization and facilitates vertical accretion‐dominated tidal channel development. Low marsh elevations result in initially slower developing vegetation colonization and channel development but are more beneficial to fish during the early stages of marsh recovery. High marsh elevations appear to sacrifice tidal channel development and associated fish access for rapid vegetation colonization. 相似文献
920.
Snails as Biomonitors of Oil-Spill and Bioremediation Strategies 总被引:3,自引:0,他引:3
L. E. J. Lee J. Stassen A. McDonald C. Culshaw A. D. Venosa K. Lee 《Bioremediation Journal》2002,6(4):373-386
Aquatic and pulmonate snails were evaluated for their suitability as biomonitors of habitat recovery following an experimental oil spill in a freshwater marshland. The mystery snail, Viviparus georgianus, and the mimic pondsnail, Pseudosuccinea columella, were used as sediment quality biomonitors for a controlled oil-spill experiment at a wetland site along the St. Lawrence River (Ste. Croix, Quebec) to assess the impacts of crude oil, rates of natural recovery, and the efficacy of bioremediation treatments to enhance the bacterial degradation of residual oil in the sediments. Sediments from control sites and oiled sites with or without the application of fertilizers as bioremediation strategies, were evaluated both in situ and under controlled laboratory conditions at various time intervals. Snail survival, growth, and histopathological changes were monitored. While V. georgianus proved to be good biomonitors, P. columella appeared unaffected by the treatments. The differing sensitivity may depend on the gastropods' feeding habits. V. georgianus being a detritivore assimilated contaminants from the sediments, while P. columella, being an herbivore, did not directly assimilate contaminants. Nevertheless, snails show potential as important and ideal “tools” for testing environmental conditions because of their abundance, ease of collection, wide distribution, and relatively sedentary nature. 相似文献