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41.
In this paper,the water quality of the Xixi Wetland was evaluated and the characteristics of water pollution were described according to the survey data.Based on the status of water quality and its functional requirements as an urban wetland,biological-ecological countermeasures were suggested.The experimental use of ecological technologies,such as artificial wetlands,ecological aquiculture and artificial floating island,were done in several fish ponds in the Xixi Wetland.Water monitoring results show that the quality of the treated water has improved significantly and the measures to purify the eutrophic water in the wetland have been effective. 相似文献
42.
本研究对邛海湖湿地水生维管植物种类及分布状况进行了调查.结果表明,邛海湖湿地现有水生维管束植物77种,隶属于25科50属.其中,蕨类植物5种,隶属2科3属;被子植物72种,隶属23科47属.从植物生态类型和生活型方面来划分,邛海水生维管束植物可分为湖区水生维管植物、河口滩涂植物和湿生植物三种类型.它们主要分布在湖泊的北面、西面和南面.区系分析结果表明,邛海水生维管束植物共有7种分布类型,其中以世界性分布型植物种最多.邛海湿地自然着生的水生植物群落破坏严重,挺水植物以上群落基本消失,浮水植物和沉水植物分布区锐减,分布深度退缩,分布密度减小.针对邛海湿地水生维管束植物存在问题,笔者提出了相应的解决方法和建议.该研究为邛海湿地的恢复和重建提供了理论依据. 相似文献
43.
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45.
闽江河口湿地生物多样性及其保护 总被引:9,自引:0,他引:9
根据闽江河口湿地比较系统的调查资料,分析了生物多样性的状况及其受人为活动影响的原因,提出了湿地生物多样性保护的对策。研究表明,闽江河口区西自闽侯竹岐,东至连江川石岛,共划分10个湿地类型,总面积约459.2km2。闽江河口众多的湿地串珠状排列,有6块面积较大的湿地,是鸟类的主要栖息、繁殖和迁徙地。闽江河口湿地的维管束植物107科337属465种,被子植物89科317属438种,大型水生无脊椎动物61种,鸟类29科118种,植被类型4种类型、18个群系和22个群丛。文中分析了环境污染、不合理开发利用、盲目围垦等人为活动对闽江口湿地生物多样性的影响,最后提出了湿地生物多样性的保护对策。 相似文献
46.
Decomposition of aboveground and belowground organs of the emergent macrophyte Z.latifolia was investigated using a litterbag technique for a period of 359 days in a freshwater marsh in Japan. Aboveground parts were
classified into: leaves, sheaths and stems. Belowground parts were classified into: horizontal rhizomes (new rhizome, hard
rhizome, soft rhizome) and vertical rhizome (stembase). The decay rate (k) was 0.0036 day−1, 0.0033 day−1 and 0.0021 day−1 for leaves, sheaths and stems, respectively. For belowground parts, the decay rate varied considerably from 0.0018 day−1 to 0.0079 day−1, according to differences in the initial chemical compositions of rhizomes. After 359 days of decay, new rhizomes lost 94%
of their original dry mass, compared with a loss of 48–84% for the other rhizomes. There was a significant positive relationship
between litter quality and decay rate for horizontal rhizomes. For the new rhizomes, which had an internal nitrogen content
of 24.2 mg N g−1 dry mass, the mass loss was 40% higher than that of soft rhizomes, which had an internal N content of 9.8 mg N g−1 dry mass. Over the period of 359 days, the nitrogen concentration in all rhizome types decreased to levels lower than initial
values, but the phosphorus concentration remained constant after an initial leaching loss. Most nitrogen and phosphorus were
lost during the first 45 days of decay. Changes in carbon to nitrogen (C:N) and carbon to phosphorus (C:P) ratios basically
followed inversed trends of the nitrogen and phosphorus concentrations. 相似文献
47.
Comparison of Soil Organic Matter in Created, Restored and Paired Natural Wetlands in North Carolina 总被引:1,自引:0,他引:1
Soil organic matter (SOM) content is a key indicator of soil quality and is correlated to a number of important soil processes
that occur in wetlands such as respiration, denitrification, and phosphorus sorption. To better understand the differences
in the SOM content of created (CW), restored (RW), and paired natural wetlands (NWs), 11 CW/RW-NW pairs were sampled in North
Carolina. The site pairs spanned a range of hydrogeomorphic (HGM) subclasses common in the Coastal Plain. The following null
hypotheses were tested: (1) SOM content of paired CW/RWs and NWs are similar; (2) SOM content of wetlands across different
HGM subclasses is similar; and (3) interactions between wetland status (CW/RW vs. NW) and hydrogeomorphic subclass are similar.
The first null hypothesis was rejected as CW/RWs had significantly lower mean SOM (11.8 ± 3.9%) than their paired NWs (28.98
± 8.0%) on average and at 10 out of the 11 individual sites. The second and third null hypotheses were also rejected as CW/RWs
and NWs in the non-riverine organic soil flat subclass had significantly higher mean SOM content (31.08 ± 14.2%) than the
other three subclasses (8.18 ± 2.5, 11.18 ± 8.2, and 10.38 ± 4.2%). Individual sites within this fourth subclass also had
significantly different SOM content. This indicated that it would be inappropriate to include the organic soil flat subclass
with either the riverine or non-riverine mineral soil flat subclasses when considering restoration guidelines. These results
also suggested that if there is a choice in mitigation options between restoration or creation, wetlands should be restored
rather than created, especially those in the non-riverine organic soil flat subclass. 相似文献
48.
Creating riverine wetlands: Ecological succession, nutrient retention, and pulsing effects 总被引:1,自引:0,他引:1
William J. Mitsch Li Zhang Christopher J. Anderson Anne E. Altor Maria E. Hernndez 《Ecological Engineering》2005,25(5):629
Successional patterns, water quality changes, and effects of hydrologic pulsing are documented for a whole-ecosystem experiment involving two created wetlands that have been subjected to continuous inflow of pumped river water for more than 10 years. At the beginning of the growing season in the first year of the experiment (1994), 2400 individuals representing 13 macrophyte species were introduced to one of the wetland basins. The other basin was an unplanted control. Patterns of succession are illustrated by macrophyte community diversity and net aboveground primary productivity, soil development, water quality changes, and nutrient retention for the two basins. The planted wetland continued to be more diverse in plant cover 10 years after planting and the unplanted wetland appeared to be more productive but more susceptible to stress. Soil color and organic content continued to change after wetland creation and wetlands had robust features of hydric soils within a few years of flooding. Organic matter content in surface soils in the wetlands increased by approximately 1% per 3-year period. Plant diversity and species differences led to some differences in the basins in macrophyte productivity, carbon sequestration, water quality changes and nutrient retention. The wetlands continued to retain nitrate–nitrogen and soluble reactive phosphorus 10 years after their creation. There are some signs that sediment and total phosphorus retention are diminishing after 10 years of river flow. Preliminary results from the beginnings of a flood pulsing experiment in the two basins in 2003–2004 are described for water quality, nutrient retention, aboveground productivity, and methane and nitrous oxide gaseous fluxes. 相似文献
49.
Managing vegetation in surface-flow wastewater-treatment wetlands for optimal treatment performance 总被引:9,自引:1,他引:8
Constructed wetlands that mimic natural marshes have been used as low-cost alternatives to conventional secondary or tertiary wastewater treatment in the U.S. for at least 30 years. However, the general level of understanding of internal treatment processes and their relation to vegetation and habitat quality has not grown in proportion to the popularity of these systems. We have studied internal processes in surface-flow constructed wastewater-treatment wetlands throughout the southwestern U.S. since 1990. At any given time, the water quality, hydraulics, water temperature, soil chemistry, available oxygen, microbial communities, macroinvertebrates, and vegetation each greatly affect the treatment capabilities of the wetland. Inside the wetland, each of these components plays a functional role and the treatment outcome depends upon how the various components interact. Vegetation plays a uniquely important role in water treatment due to the large number of functions it supports, particularly with regard to nitrogen transformations. However, it has been our experience that vegetation management is critical for achieving and sustaining optimal treatment function. Effective water treatment function and good wildlife quality within a surface-flow constructed wetland depend upon the health and sustainability of the vegetation. We suggest that an effective tool to manage and sustain healthy vegetation is the use of hummocks, which are shallow emergent plant beds within the wetland, positioned perpendicular to the water flow path and surrounded by water sufficiently deep to limit further emergent vegetation expansion. In this paper, we describe the use of a hummock configuration, in conjunction with seasonal water level fluctuations, to manage the vegetation and maintain the treatment function of wastewater-treatment wetlands on a sustainable basis. 相似文献
50.
Scott C. Neubauer Gloried E. Toledo-Durán David Emerson J. Patrick Megonigal 《Geomicrobiology journal》2013,30(1):65-71
In the wetland rhizosphere, high densities of lithotrophic Fe(II)-oxidizing bacteria (FeOB) and a favorable environment (i.e., high Fe(II) availability and microaerobic conditions) suggest that these organisms are actively contributing to the formation of Fe plaque on plant roots. We manipulated the presence/absence of an Fe(II)-oxidizing bacterium (Sideroxydans paludicola, strain BrT) in axenic hydroponic microcosms containing the roots of intact Juncus effusus (soft rush) plants to determine if FeOB affected total rates of rhizosphere Fe(II) oxidation and Fe plaque accumulation. Our experimental data highlight the importance of both FeOB and plants in influencing short-term rates of rhizosphere Fe oxidation. Over time scales ca. 1 wk, the FeOB increased Fe(II) oxidation rates by 1.3 to 1.7 times relative to FeOB-free microcosms. Across multiple experimental trials, Fe(II) oxidation rates were significantly correlated with root biomass, reflecting the importance of radial O 2 loss in supporting rhizosphere Fe(II) oxidation. Rates of root Fe(III) plaque accumulation (time scales: 3 to 6 wk) were ~ 70 to 83% lower than expected based on the short-term Fe(II) oxidation rates and were unaffected by the presence/absence of FeOB. Decreasing rates of Fe(II) oxidation and Fe(III) plaque accumulation with increasing time scales indicate changes in rates of Fe(II) diffusion and radial O 2 loss, shifts in the location of Fe oxide accumulation, or temporal changes in the microbial community within the microcosms. The microcosms used herein replicated many of the environmental characteristics of wetland systems and allowed us to demonstrate that FeOB can stimulate rates of Fe(II) oxidation in the wetland rhizosphere, a finding that has implications for the biogeochemical cycling of carbon, metals, and nutrients in wetland ecosystems. 相似文献