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61.
河口悬浮物中磷的化学形态分布与转化   总被引:11,自引:2,他引:11  
杨逸萍  胡明辉 《台湾海峡》1995,14(4):313-319
本文研究长江口和九龙江口悬的中磷的化学形态分布及不同环境条件下的转化与释放。结果表明,长江口和九龙江口悬浮物中易于溶解释放的非磷灰石无机磷分别占总磷含量之21.3%和48.1%。水体盐度增大、缺氧环境以及海洋浮游植物渗出物和海洋细菌的作用,均可不同程度也促进悬浮物中磷释放到水相,同时引起固相内部磷形态的转化。  相似文献   
62.
Phosphorus (P) concentration in the atmospheric aerosol was measured at a northwestern Mediterranean coastal site. Airborne P ranged between 25 and 85 ng m(-3) (geometric mean: 51 ng m(-3)). Due to a significant contribution (about 90%) of anthropogenic land-based source emissions, dry deposition velocities of 0.1-0.5 cm s(-1) were used to estimate a dry flux of 0.15-0.7 micromol P m(-2) day(-1). The theoretical impact of the dry flux on primary production (0.1-0.4 mg C m(-2) day(-1)) is 50-200-fold lower than that of a single significant wet event. The incineration plant of the Nice district is identified as a possible major source of airborne anthropogenic P. As the implementation of waste plants is currently expanding along the western European shores, the importance of the P atmospheric source to the western Mediterranean is likely to increase with time.  相似文献   
63.
Nutrient loads from the land to the sea must be reduced to combat coastal eutrophication. It has been suggested that further mitigation efforts are needed in the brackish Baltic Sea to decrease nutrients, especially in eutrophic coastal areas. Mussel farming is a potential measure to remove nutrients directly from the sea. Mussels consume phytoplankton containing nitrogen (N) and phosphorus (P); when the mussels are harvested these nutrients are removed from the aquatic system. However, sedimentation of organic material in faeces and pseudo-faeces below a mussel farm consumes oxygen and can lead to hypoxic or even anoxic sediments causing an increased sediment release of ammonium and phosphate. Moreover, N losses from denitrification can be reduced due to low oxygen and reduced numbers of bioturbating organisms. To reveal if mussel farming is a cost-effective mitigation measure in the Baltic Sea the potential for enhanced sediment nutrient release must be assessed.  相似文献   
64.
生物炭作为海绵城市雨水滞留池填料的效果初探   总被引:1,自引:0,他引:1  
生物炭吸附性强、抗氧化,在海绵城市建设中具有广阔的应用前景。通过模拟渗水实验,对土壤、生物炭和土壤生物炭混合物等对雨水吸持和净化效果进行研究。结果表明:以生物炭作为滞留池填料,具有较好的储水能力,储水量达0.45 mL/mL;能够缓冲酸性地表径流雨水的pH值,模拟雨水pH值从6.34提升至7.82;对雨水中总氮、总磷和铵氮的截留率分别为34.4%、48.0%和35.0%。因此,生物炭可作为海绵城市建设中雨水滞留池的新型填料。  相似文献   
65.
饮马河流域典型湿地植物净化河流水环境效果研究   总被引:1,自引:0,他引:1  
采取单种及混种方式,通过小型湿地模拟实验,研究松花江支流饮马河流域河流湿地中常见的芦苇、香蒲、槽秆荸荠、藨草、慈姑、花蔺、菱角、紫背浮萍和金鱼藻9种湿地植物及其组合对河流水体中化学需氧量(COD_(cr))、氮、磷等的净化效果。结果表明:所选湿地植物,在模拟环境条件下均能有效提升取自河流水体的水质;不同的湿地植物对污水中各污染物净化具有明显的差异,花蔺对总磷(TP)、COD_(cr)和氨氮(NH_3-N)净化效果最好,去除率依次为99.65%、68.22%和99.54%;香蒲、菱角、金鱼藻混合组对总氮(TN)的净化效果最好,去除率是66.19%;槽杆荸荠、芦苇和金鱼藻对亚硝酸盐氮(NO_2-N)的净化效果最好,去除率是83.64%。两种植物混种后对某一种污染物指标的处理效果弱于分别独种时的处理效果,但对多种污染物指标的综合处理效果一般要好于独种时的处理效果。  相似文献   
66.
地表径流挟带土壤氮进入水体是造成水体面源污染的主要途径之一。本研究依区域年降雨量的差异,将抚仙湖磷矿开采区年降雨量分别为1200-1300mm和1000-1100min的区域划分为东大河流域磷矿区和帽天山磷矿区两个研究单元,通过设置野外径流小区,在自然降雨状态下对磷矿开采废弃地与矿区现有主要植被类型土壤营养元全氮随径流流失量进行比较研究。研究结果表明:降雨强度是矿山废弃地产流的关键因子,在大、暴雨状态下矿山废弃地土壤TN流失量远大于各植被类型,对抚仙湖水质产生不利的影响。各植被类型土壤TN随径流流失量主要取决于地表径流量,径流中TN含量对其影响不大,流失总量次序与径流总量次序相一致,表现为:灌草丛〉云南松灌丛〉云南松混交林〉华山松林〉竹林〉桉树林,除灌草丛外各植被类型均能对土壤TN流失起到较强的截留作用。  相似文献   
67.
The primary producer community of Lake Apopka, a large (125 km2), shallow (mean depth, 1.7 m), polymictic Florida lake, shifted from macrophyte dominance to phytoplankton dominance in the 1940s. Today, frequent wind resuspension of highly organic, unconsolidated sediments supports a meroplanktonic community that is predominantly diatoms, but during calm periods the algal community is dominated by planktonic cyanobacteria. Sedimentary algal pigments (chlorophyll derivatives and carotenoids) and chemical proxies for nutrient enrichment (polyphosphate, total phosphorus and biogenic silica) in three sediment cores were used to investigate historic changes in primary producers. Sediments were separated into three stratigraphic zones using multivariate statistical techniques. Stratigraphic zonation was established in each core although sediment deposition at one site was insufficient to adequately resolve temporal changes. These results show the importance of selecting suitable sites for paleolimnological studies. The oldest zone represents macrophyte-derived sediments, and the two overlying zones represent phytoplankton-derived sediments deposited since the 1940s. Algal pigments in the most recent sediment zone show little degradation, which might be due to the presence of viable meroplankton in the sediment. After the initial primary producer shift from macrophytes to phytoplankton, the lake experienced a short period of cyanobacterial dominance followed by a period of benthic diatom abundance before being replaced by the present algal community consisting of cyanobacteria and meroplanktonic diatoms. Chlorophyll derivatives and carotenoids were highly correlated with total phosphorus. Historic trends inferred from the data include algal and cyanobacterial productivity that increased with increased phosphorus loading. The study demonstrates that valid paleolimnological proxies for historic eutrophication are available in loosely consolidated sediments of shallow, subtropical lakes.  相似文献   
68.
韦海英  柴立和 《湖泊科学》2006,18(6):557-564
本文在假设湖泊受单一营养盐磷限制和不考虑湖底沉积物影响的情形下,建立了一个单层箱体磷循环的非线性动力学模型,研究湖泊中颗粒磷、可溶性磷和藻类中的磷这三种磷之间的相互关系,理论上分析了磷循环系统的稳定特性,得出三种形式的磷共存是系统趋向稳定的平衡点.然后论文又从人工治理的角度,通过数值计算综合考虑外源性磷、水力冲刷、生物调控和基质浓度因素对磷循环的影响,分析不同因素的改变对系统和湖泊水质的影响,进而对这一类的富营养化现象防治提供可行性的工程上的实际建议.  相似文献   
69.
P, Fe, Mn, and S species were analyzed in water samples from the sediment-water interface collected at four seasonally different times during the course of a year at two sampling sites in the southern basin of Lake Lugano (Lago di Lugano). The results reveal the strong influence of the biogeochemical processes in the sediment on the chemical composition of the lake water above. Consumption of oxygen and nitrate under oxic to microoxic conditions in the water column as well as sequential release of reduced manganese and iron under anoxic conditions was observed as a direct or indirect consequence of microbially mediated degradation of organic matter. The seasonal pattern observed for the release and the retainment of dissolved reduced iron and manganese correlates well with the one for dissolved phosphate. Iron, manganese and phosphorus cycling are coupled tightly in these sediments. Both sediment types act as sinks for hydrogen sulfide and sulfate. An inner-sedimentary sulfur cycle is proposed to couple iron, manganese and phosphorus cycling with the degradation of organic matter. Nutrient cycling at the sediment-water interface might thus be driven by a microbially regulated electron pumping mechanism. The results contribute to a better understanding of the role of sediment processes in the lake's internal phosphorus cycle and its seasonal dynamics.  相似文献   
70.
Nutrient and Oxygen Balance of a Highly Polluted Treated Sewage Channel with Special Regard to the Submerged Macrophytes The changes of the concentrations of inorganic nitrogen compounds, orthophosphate, and oxygen were measured in the flowing wave along the flowing stretch of the Berlin treated sewage channel Wuhle monthly over a period of two years (1993/94) to estimate the nutrient and oxygen balances. This treated sewage channel is rich in nutrients and densely covered with submerged macrophytes. During the period of investigation in 1993 (1994), the effluent of the sewage treatment plant Falkenberg, which is lacking in adjustable nitrification and denitrification. contained in average 16.1 (12.7) mg/L of NH-N, 13.7 (9.4) mg/L of NO3?-N. 0.94 (0.69) mg/L of NO-N. and 0.36 (0.26) mg/L of PO-P. Due to the neglectable influence of other processes like nutrient uptake by submerged macrophytes and algae, desorption of ammonia or dilution, the changes of the concentrations of the inorganic nitrogen compounds are mainly influenced by nitrification and denitrification. The nitrification is mainly done by sessile nitrifiers in the treated sewage channel Wuhle. The nitrification rates. calculated from the decrease of the ammonium concentrations, were between 0.5 and 20 g/(m2d) related to the flowing stretch area. The ammonium concentrations decreased along the flowing stretch in average by 20 to 44%. The highest nitrification rates could be found at the stretches with a dense colonization with submerged macrophytes and a good oxygen supply due to low water depth and high flowing velocities. The denitrification rates, calculated from the decrease of the total of the concentrations of the inorganic nitrogen compounds, were between 0.5 and 23 g/(m2d) related to the flowing stretch area. The total loss of nitrogen due to denitrification was between 10 and 20% along the flowing stretch of the treated sewage channel Wuhle. This corresponds to a total amount of up to 530 kg nitrogen per day. The main part of the phosphorus occured as orthophosphate in concentrations between 0.04 and 0.87 mg/L of PO-P in the effluent of the treatment sewage plant Falkenberg. The orthophosphate concentration changed along the flowing stretch mostly in such a manner that it were at the same level at the end of the flowing stretch at the mouth into the river Spree. The self-purification capacity of the channel does not lead to a relevant reduction of the very high nutrient load under the present conditions. The rates of the photosynthetic production (P) and the community respiration (R) were calculated from the rates of the total changes of oxygen with regard to the physical aeration. The rates of the photosynthetic production were between 0 and 33 g/(m2d), the rates of the community respiration between 15 and 75 g/(m2d). Therewith, the Wuhle treatment sewage channel belongs to the very productive waters. A positive balance (P > R) could only be measured on two segments in May. The rates of oxygen production depend on the ratio width to depth of the water. It is possible that the positive influence of the submerged macrophytes on the oxygen balance also at higher biomasses than 250 g/m2 (as dry weight) predominates at the segments with a favourable ratio. The portion of the oxygen input through diffusion along the flowing stretch and at the weirs was 30%, respectively, that of the photosynthic production 40% in summer. The rates of community respiration decreased along the flowing stretch by 50 to 90%. The nitrification had the main portion of the oxygen depletion in the Wuhle treated sewage channel with 60…80%. Despite the high biomass, the respiration of the submerged macrophytes had only a small portion of the total oxygen depletion. Nevertheless, the submerged macrophytes contributed to the nearly total oxygen depletion at the most densely covered segment 2 at night. The decrease of the content of particular organic material and the ammonia concentrations at the effluent of the sewage treatment plant, a diminishing of the biomass of submerged macrophytes by shading, and the widening of a few flowing stretches are demanded for the improvement of the oxygen balance of the Wuhle treated sewage channel.  相似文献   
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