新兴绿色技术——水生植物修复技术

水体富营养化治理已成为当今世界性难题,解决水体富营养化问题的关键是调控水生生态系统结构,使其恢复自然、健康和稳定的水生生态系统功能,提高水生生态系统的生物净化能力.水生植物是水生生态系统中最重要的初级生产者,在水生生态系统物质和能量循环中处于十分重要的地位.水生植物修复技术具有投资、维护和运行费用低,管理简便,处理效果好,可改善和恢复生态环境,回收资源和能源以及收获经济植物等优点,浮岛技术、人工湿地等技术也取得了显著的成就.植物修复技术作为一种绿色技术,将会有更加广阔的发展天地.     

水产品收购价格预测的时序组合模型研究

我国水产品市场已经出现了区域性、结构性的供大于求及价格持续下降的现象。为此，对水产品价格进行预测是必要的。以1978～1999年数据为样本，利用时序组合模型对2000年的水产品收购价格进行了预测研究。     

4种水生植物对水体水质的影响

以长沙地区现有水生植物就观赏性进行调查分析,采集黄菖蒲、荸荠、海寿花、绶草进行50 d的观察测定,分析这4种水生植物对供试水体的色度,含氧量,以及氮、磷含量的影响。结果表明:4种水生植物水体中DO的含量为荸荠>绶草>黄菖蒲>海寿花;水体浊度为绶草>荸荠>黄菖蒲>海寿花;水中TP含量为绶草>黄菖蒲>海寿花>荸荠;水中TN含量为绶草>荸荠>海寿花>黄菖蒲。种植4种水生植物的水体pH值在7.5~8.5之间。黄菖蒲和海寿花的长势比另外两种植物的好,海寿花水体浊度最低,景观效果最明显。     

低值水产品及水产副产品的加工与综合利用

低值水产品及其副产品通常经过简单加工后被作为饲料利用或直接作为废物丢弃,不仅造成资源浪费,而且造成对环境的污染。研究表明,利用高新技术,可以把低值水产品或水产品下脚料加工成功能性鱼油制品、新型鱼糜制品、海鲜调味品和营养丰富的水解鱼蛋白饲料等高附加值的产品,以及骨糊、硫酸软骨素和骨胶等功能性添加剂。这些产品的研究开发为低值水产品及副产品的加工利用提供了新的途径。     

汉江水源区生态沟渠对径流氮、磷的生态拦截效应

[目的]研究汉江水源区生态沟渠对径流氮、磷的生态拦截效应,为农业非点源污染的控制提供重要参考和依据。[方法]设置生态沟渠在不同时间对不同断面水体进行监测。[结果]同段沟渠内,侧面外来水对沟渠径流氮浓度变化影响比磷浓度变化明显;径流TN,NO3-N浓度在上游、中游和下游断面变异系数分别达到19.81%~31.88%,9.57%~16.73%和32.14%~42.81%;NH+4-N和TP在4个断面变异系数在33.33%~88.46%范围内变化;生态沟渠断面之间,水草拦截净化沟渠段氮、磷含量降低幅度在9.52%~31.11%。[结论]沟渠生态拦截对径流氮素净化效果较明显,同时适当布局拦沙工程可以削减磷素流失。     

Effect of reduced tillage on weeds and soil organisms in winter wheat and summer maize cropping on Humic Andosols in Central Japan

Although reduced tillage (RT) may preserve soil biota and improve the productivity and sustainability of arable lands in temperate regions, the extension of RT is limited by difficulties in controlling weeds. We studied the effect of RT without herbicide application on weed communities and soil biota in a 1-year 2-crop rotation system with winter wheat (Triticum aestivum L.) and maize (Zea mays L.) on Andosols in Japan. RT of the surface 3 cm and conventional moldboard plowing (CT) were conducted before seeding twice per year. For the first 3 years, from autumn 1997 to spring 2000, one field was managed with RT and another with CT. For the second 3 years, from autumn 2000 to spring 2003, RT and CT were conducted in two replicated plots in each field. Weed communities and soil biota were studied in the last 2 years. Dominant weed species in winter wheat cropping were Italian ryegrass (Lolium multiflorum Lam.) in 2002 and common vetch (Vicia angustifolia L.) in 2003, and their biomass was high where RT or CT was continuously conducted. Switching of tillage methods, from RT to CT or vice versa, reduced the biomass of winter weeds. In summer maize cropping, several annual and perennial weed species tended to increase under RT in the second 3 years. However, redroot pigweed (Amaranthus retroflexus L.), the most dominant weed in 2002 and 2003, responded to tillage inconsistently and its biomass was not always increased by RT. Species diversity of winter weeds was decreased by CT conducted in the first 3 years, and that of summer weeds was decreased by CT conducted in the second 3 years. The seedbank in the 0–10-cm soil layer under recent RT was large (7200–16 300 seeds m⁻²) compared with that under CT (2900–7300 seeds m⁻²). The microbial substrate-induced respiration (SIR) and the population densities of nematodes and mites were higher under RT in the second 3 years and were not affected by previous tillage practices. Both were highly correlated with soil total nitrogen. The positive effect of RT on these soil organisms was primarily attributable to the accumulation of organic matter in soil, but not to plant cover as a result of incomplete weed control by RT. Occasional adoption of RT in current CT systems may be effective at enriching soil organisms with little risk of weed infestation.     

模拟池塘中锶-89的迁移和积累动力学

采用放射性同位素示踪技术研究了核污染关键核素之一——~(89)Sr在水生生态系中的动力学行为。当示踪剂~(89)Sr一次性引入水系后,即向系统内的动植物及底泥迁移,从而使系统各组分中~(89)Sr-Sr的量均随时间变化。结果表明:1.在试验期间,池水中~(89)Sr-Sr的含量随时间减少,6d后由原来的1.76 ppm降至1.01ppm,11d后已不到原来的一半,第35d时只及原始量的30％。2.池水中的~(89)Sr-Sr向系统各组分中的迁移速率和数量因组分的性质而异。比如底泥,1d后由原始的0增加到7.07 ppm,11d后趋向平衡,以后几乎不再增加;~(89)Sr-Sr在鱼和螺蛳体内的含量在试验期间均随时间增加,35d时分别由原始的0增加到18.73ppm和48.28ppm;在处理当天,金鱼藻中~(89)Sr-Sr虽增加较快,由原始的0增至6.68 ppm,但4h后却几乎不再增加。3.水生动植物对放射性锶都有一定的浓集作用,最大的浓集系数分别为:螺蛳94.7,鱼36.7,金鱼藻只有12.6。可见,贝壳类动物对水系中的放射性锶有较强的去污能力。     

A Novel Particle Contact Assay with the Yeast Saccharomyces cerevisiae (8 pp)

Goal, Scope and Background   Numerous xenobiotics released into surface waters are transferred to suspended particulate matter and finally attached to sediments. Aquatic organisms may be exposed to them by direct particle feeding, by physical contact with contaminated surfaces as an exposure route, and by the uptake of dissolved contaminants after equilibration via the free water phase. In order to assess potential sediment toxicity, each of these exposure routes has to be addressed. This paper presents a newly developed particle contact assay that uses the fermentation performance of a specific Saccharomyces cerevisiae strain for the assessment of toxic effects in sediments. The test procedure is based on the characteristic feature of growing yeast cells to attach to sediment particles, which are also relevant for the accumulation of contaminants. The physical contact with lipophilic contaminants mirrors an exposition pathway for the direct uptake into the cells. In order to quantitatively characterize the toxic effects of particle attached pollutants on the fermentation performance, unpolluted native reference sediment was spiked with representatives for widely distributed anthropogenic contaminants. Methods   Saccharomyces cerevisiae was established as sensitive eukaryotic microorganism for the ecotoxicological assessment of particle attached anthropogenic contaminants in freshwater sediments. For this purpose, yeast cells were cultivated in sediment samples and the resulting fermentation performance was continuously measured. Sediments artifically spiked with HCB, PCB, g-HCH, DDT, and benzo(a)pyrene and solutions of each contaminant were comparatively investigated by means of their adverse effects on yeast fermentation performance. Additionally, four native river sediments characterized by increasing levels of pollution were assessed by the yeast particle contact assay, and simultaneously by standard aquatic tests with algae, daphniae, and luminescent bacteria using pore water and elutriates. Results of the bioassays were related to specific sediment contamination with respect to metals and organic priority pollutants. Results and Discussion   In sediments spiked with PCB and benzo(a)pyrene fermentation, performance was affected extensively below concentrations inhibiting fermentation in contaminant solutions. This suggests a high efficiency of the exposure route by physical contact. The fermentation performance was only slightly affected by single lipophilic pollutants, whereas mixtures of individually spiked sediments caused critically reduced fermentation performance suggesting additive synergistic effects. Native river sediments modestly to critically polluted by hazardous organic compounds lead to a slightly to dangerously reduced fermentation performance in the yeast contact assay. These inhibitory effects were much less pronounced in the standard bioassays conducted with algae, daphniae and luminescent bacteria, applying pore waters and elutriates as sample matrices. Using pore water, inhibition was measured only in the most polluted sediment, elutriates lead to a slight inhibition of the algal growth in the undiluted sample only. These results indicate an improved sensitivity of the yeast particle contact assay compared to the standard assays, due to uptake and physical cell contact as additional routes of exposure. Conclusion   The yeast particle contact assay is a valuable tool for the assessment of ecotoxicological potential in freshwater sediments. Since the assay addresses physical contact as an exposure route, it indicates bioavailability of lipophilic compounds in sediments. Outlook   The sensitive indication of bioavailable contaminants associated to sediment particles by the newly developed yeast particle contact assay recommends it as a complementary microbial bioassay in a test battery for assessing major pathways of contaminants in whole sediments.     

Do plant species encourage soil biota that specialise in the rapid decomposition of their litter?

Plants are often nutrient limited and soil organisms are important in mediating nutrient availability to plants. Thus, there may be a selective advantage to plants that alter the soil community in ways that enhance the decomposition of their litter and, hence, their ability to access nutrients. We incubated litter from three tree species (Fagus sylvatica, Acer pseudoplatanus and Picea sitchensis) in the presence of biota extracted from soil beneath a stand of each species to test the hypothesis that litter decomposes fastest in the presence of biota derived from soil where that species is locally abundant. We found that respiration rate, a measure of decomposer activity and carbon mineralisation, was affected by litter type and source of soil biota, whereas, mass loss was only affected by litter type. However, litter from each tree species did not decompose faster in the presence of indigenous soil biota. These findings, therefore, provide no support for the notion that woodland plants encourage the development of soil communities that rapidly decompose their litter.     

水生植物对水体中氮、磷的吸收与抑藻效应的研究

研究了不同水生植物对富营养化水体氮、磷的净化效果及其抑藻效应。结果表明:金鱼藻(Ceratophyllum demersum)、苦草(Vallisneria spiralis)、空心菜(Ipomoea aquatica)、浮萍(Lemna minor)和菹草(Potamogetom crispusLinn)对富营养化水体中总氮、总磷、硝态氮、氨氮都有较好的去除作用,其中以空心菜和金鱼藻效果最好。培养21d后的空心菜对总氮和硝态氮的吸收率分别为76.93%和71.9%;培养21d后的金鱼藻对总磷和氨氮的吸收率分别达到了93.15%和91.2%。水葫芦(Eichhornia crassipes)、金鱼藻、浮萍都具有较好的抑制藻类生长的作用,培养过以上3种水生植物的水体也表现出抑藻效应。