酸雨对温州三土羊湿地水体氮营养盐数量的影响

为了解酸雨对温州三羊湿地水体氮营养盐数量的影响,本文测定了三土羊湿地水体中不同形态氮的含量,其中氨氮2.90～10.75 mg·L^-1,平均538 mg·L^-1、硝态氮0.16～0.44 mg·L^-1,平均0.31 mg·L^-1;总氮34.04～63.20 mg·L^-1,平均55.75 mg·L^-1和水体的pH值,6.1～6.5,平均6.4;并测算了近两年通过降水输入到三羊湿地和三羊湿地水体中不同形态氮的数量及其占湿地现有水体中各形态氮的比例,其中输入到三羊湿地氨氮、硝态氮和总氮的量分别为2.48～2.86×10⁴ kg、2.87×10⁴～4.96×10⁴ kg和5.35×10⁴～7.82×10⁴ kg,分别占湿地水体现有量的56%～64%、11.21～19.38倍和12%～17%;直接输送到三羊湿地水体各形态氮的数量0.72×10⁴～0.84×10⁴ kg、0.83×10⁴～1.44×10⁴ kg和1.55×10⁴～2.27×10⁴,分别占现有量的16%～19%,3.24～5.63倍和3%～5%.结果表明,酸雨是三,羊湿地水体氮污染的主要来源之一,对三羊湿地水体富营养化产生重要影响.     

Factors affecting nitrification in situ in a heated stream.

Nitrification, previously shown to occur in the stream under study, ensued only when the stream received heated (28 degree C or above) discharges and was negligible when water temperatures were 17 degree C or lower. The most probable number os ammonium oxidizer in stream bed sediments exceeded intrite oxidizers by ratios of 43:1 to 1,113:1, and the average rate of ammonium oxidation in this stream, 0.50 mg of NH4-N/liter per h exceeded the rate of nitrite oxidation, 0.29 mg of NO2-N/liter per h, resulting in an accumulation of nitrite. Nitrification rates were influenced by the dissolved oxygen concentration, increasing during daylight hours and exhibiting maximum rates during the summer months.     

上海地区大气氮湿沉降及其对湿地水环境的影响

根据1998～2003年上海地区雨水中NO₃^--N、NH₄⁺-N浓度,采用单因子评估模式评价了降雨对湿地水环境的影响,并结合降雨量数据,研究了大气湿沉降氮通量.结果表明,上海地区雨水中氮浓度较高,6年雨水平均硝态氮浓度为259 mg·L^-1,铵态氮浓度为2.16 mg·L^-1,总无机氮（TIN）浓度474 mg·L^-1,远大于水体富营养水中氮浓度阀值（0.2 mg·L^-1）,依据降水中的氮浓度,降水已达到地表水V类、劣V类水平.6年湿沉降氮通量平均值为58.1 kg·hm^-2·yr^-1,其中NO₃^--N占54%.大气氮沉降对湿地水体富营养化影响值得关注.     

真江蓠(Gracilaria verrucosa)对网箱养殖海区的生态修复及生态养殖匹配模式

2006年8～9月,在浙江象山港花鲈(Lateolabrax japonicus)养殖网箱中吊养真江蓠(Gracilaria verrucosa)对网箱养殖造成的水体富营养化进行生态修复研究.通过45d内的平面监测、定点跟踪监测和断面监测,结果表明:该网箱养殖区水体呈严重富营养化状态,营养状态指数(E)为32.00,其营养盐分布由高浓度的中心区向周围150m非养殖水域扩散;真江蓠对养殖区的富营养化海水具有较好的修复效果:江蓠生态修复区及其相邻网箱中水体PO4-P、NO2-N、NH4-N和NO3-N含量显著低于非修复区(P＜0.01),修复区海水PO4-P、NO2-N、NH4-N和NO3-N浓度比非修复区分别降低22%～58%、24%～48%、22%～61%和24%～47%.养殖真江蓠45d后,修复区水体DO浓度和透明度显著高于非修复区(P＜0.05),DO平均提高28%,透明度平均提高30%;而修复区水体Chl-a浓度显著低于非修复区(P＜0.05),平均降低49%.通过建立基于N平衡的鱼藻生态养殖模式,每收获1kg花鲈至少需要匹配江蓠4.7 kg wet wt才可实现对鱼类排放N的完全吸收.因此网箱内栽培江蓠的混合生态养殖模式,可平衡因经济动物养殖所带来的额外营养负荷,有利于实现动物养殖环境的自我修复.     

Potential of constructed wetlands in treating the eutrophic water: evidence from Taihu Lake of China

Three parallel units of pilot-scale constructed wetlands (CWs), i.e., vertical subsurface flow (VSF), horizontal subsurface flow (HSF) and free water surface flow (FWS) wetland were experimented to assess their capabilities in purifying eutrophic water of Taihu Lake, China. Lake water was continuously pumped into the CWs at a hydraulic loading rate of 0.64 m d(-1) for each treatment. One year's performance displayed that average removal rates of chemical oxygen demand (COD), ammonia nitrogen (NH(4)(+)-N), nitrate nitrogen (NO(3)(-)-N), total nitrogen (TN) and total phosphorous (TP) were 17-40%, 23-46%, 34-65%, 20-52% and 35-66%, respectively. The VSF and HSF showed statistically similar high potential for nutrients removal except NH(4)(+)-N, with the former being 14% higher than that of the latter. However, the FWS wetland showed the least effect compared to the VSF and HSF at the high hydraulic loading rate. Mean effluent TP concentrations in VSF (0.056 mg L(-1)) and HSF (0.052 mg L(-1)) nearly reached Grade III (0.05 mg L(-1) for lakes and reserviors) water quality standard of China. Wetland plants (Typha angustifolia) grew well in the three CWs. We noted that plant uptake and storage were both important factors responsible for nitrogen and phosphorous removal in the three CWs. However, harvesting of the above ground biomass contributed 20% N and 57% P of the total N and P removed in FWS wetland, whereas it accounted for only 5% and 7% N, and 14% and 17% P of the total N and P removed in VSF and HSF CWs, respectively. Our findings suggest that the constructed wetlands could well treat the eutrophic lake waters in Taihu. If land limiting is considered, VSF and HSF are more appropriate than FWS under higher hydraulic loading rate.     

Laboratory and field evaluation of broiler litter nitrogen mineralization

Two studies were conducted for this research. First, a laboratory incubation to quantify broiler litter N mineralization with the following treatments: two soil moisture regimes, constant at 60% water fill pore space (WFPS) and fluctuating (60-30% WFPS), three soil types, Brooksville silty clay loam, Ruston sandy loam from Mississippi, and Catlin silt loam from Illinois. Second, a field incubation study to quantify broiler litter N mineralization using similar soils and litter application rates as the laboratory incubation. Broiler litter was applied at an equivalent rate of 350 kg total N ha(-1) for both studies except for control treatments. Subsamples were taken at different timing for both experiments for NO3-N and NH4-N determinations. In the laboratory experiment, soil moisture regimes had no significant impact on litter-derived inorganic N. Total litter-derived inorganic N across all treatments increased from 23 mg kg(-1) at time 0, to 159 mg kg(-1) at 93 d after litter application. Significant differences were observed among the soil types. Net litter-derived inorganic N was greater for Brooksville followed by Ruston and Catlin soils. For both studies and all soils, NH4-N content decreased while NO3-N content increased indicating a rapid nitrification of the mineralized litter N. Litter mineralization in the field study followed the same trend as the laboratory study but resulted in much lower net inorganic N, presumably due to environmental conditions such as precipitation and temperature, which may have resulted in more denitrification and immobilization of mineralized litter N. Litter-derived inorganic N from the field study was greater for Ruston than Brooksville. Due to no impact by soil moisture regimes, additional studies are warranted in order to develop predictive relationships to quantify broiler litter N availability.     

Methane emission potential and increased efficiency of a phytoremediation system bioaugmented with Bacillus firmus XJSL 1-10

Horizontal subsurface flow constructed wetland mesocosms (HSSCW) designed to treat municipal waste water were bioaugmented with Bacillus firmus XJSL 1-10. The efficiencies of the three HSSCW mesocosms (non-vegetated HSSCW, Schoenoplectus validus HSSCW and Bambusa vulgaris HSSCW) were assessed. Bioaugmentation not only enhanced the efficiency of the phytoremediation system but also reduced methane emission from an average of 51.3 mg/m2/d to 21.6 mg/m2/d in Schoenoplectus validus HSSCW and from an average of 1708 mg/m2/d to 1473 mg/m2/d in Bambusa vulgaris HSSCW. Each of the three types of bioaugmented HSSCWs showed higher purification efficiency with respect to the removal of BOD and NH4-N than the non-bioaugmented HSSCWs. The performance enhancement was most significant in bioaugmented Schoenoplectus validus HSSCW mesocosm with 48.8 and 44.8% lower BOD, and NH4-N, respectively than the non-bioaugmented HSSCW.     

Some effects of low oxygen tensions on the distribution of the three-spined stickleback Gasterosteus aculeatus L. and the nine-spined stickleback Pungitius pungitius (L.)

During extensive sampling of populations of sticklebacks for parasites, it became apparent that marked differences existed in the distribution of the 2 British freshwater species. Observation of the survival, respiratory rates and distribution of three- and nine-spined sticklebacks from a variety of habitats supports the suggestion that physiologically, the nine-spined stickleback is much better adapted to life in closed, shallow, weedy, eutrophic waters, depleted in oxygen. By comparison, Gasterosteus aculeatus favours more open well oxygenated water.     

西双版纳不同热带森林下土壤铵态氮和硝态氮动态研究

用顶盖埋管法(Close-Top Tube Incubations)就西双版纳3种热带森林（热带季节雨林、片断热带雨林、橡胶林）研究了土壤铵态氮（NH４-N）和硝态氮（NO３-N）以及土壤氮素矿化速率的季节动态情况。结果表明：西双版纳3种不同林型土壤NH４-N、NO３-N和氮素矿化速率均具有明显的季节性变化。NH４-N以干热季（4月末）最高（平均为26.92 mg*kg－1）和干季（2月末）最低(平均为12.01 mg*kg－1);NO３-N则以雨季中期（7月中旬）最高(平均为8.9 mg*kg－1）和干季（2月末）最低(平均为4.04 mg*kg－1）;矿化速率则以干热季（(2月末～4月末)最高(平均为0.496 mg*kg－1*d－1）,以雨季（7月中旬～11月初）最低(平均为0.0037 mg*kg－1*d－1）。就不同林型而言,季节雨林年均氮矿化速率(0.319 mg*kg－1*d－1)>片断热带雨林(0.25 mg*kg－1*d－1)>橡胶林(0.074 mg*kg－1*d－1)。     

有机酸去除污泥重金属前后硝态氮和铵态氮浓度变化

研究了柠檬酸、草酸和乙酸溶液对污泥中重金属(Cd、Pb、Cu和Zn)的去除效果,以及处理前后析出液和污泥中硝态氮和铵态氮的浓度变化.结果表明,0.8mol.L-1柠檬酸溶液可去除污泥中76.0%的Pb和92.5%的Zn,是较好的重金属去除剂.污泥经有机酸处理后,有大量的硝态氮和铵态氮溶解于析出液中,与加入蒸馏水的对照处理相比,有机酸可大幅度增加析出液中铵态氮的含量,减少硝态氮含量.由于污泥处理过程中有其他形态的氮的转化,处理后污泥中仍含有较高浓度的硝态氮和铵态氮.0.5mol.L-1草酸处理的析出液中硝态氮和铵态氮浓度分别为2.8和888.1mg.L-1,且重金属含量不高,可作为较好的液体肥料进行回收利用.     

水稻土模拟土柱中肥料氮素的迁移转化特征

为了明确肥料氮素在模拟土柱中的迁移转化特征,通过布置室内模拟土柱试验,研究了3倍常规施肥水平下（360 mg·kg^-1）水稻土中矿质氮的变化.结果表明： 不同处理、不同土层间NH₄⁺-N和NO₃^--N含量差异显著.不施肥对照在整个培养期间养分含量变化不大,不同土层间亦没有显著性差异.施用尿素和硫铵后,土壤NH₄⁺-N和NO₃^--N含量显著提高,尤其是0～50 mm土层内,分别达到186.0～2882.1 mg·kg^-1和268.7～351.5 mg·kg^-1,分别相当于对照的4.8～242倍和5.7～316倍,50 mm以下各土层与对照处理相似,表明肥料氮素的迁移转化主要发生在0～50 mm土层内,并且在培养的前14 d变化最大.整个培养期间不同土层内,硫铵处理不同矿质态氮含量是尿素处理的0.7～2.0倍,硝化率是尿素处理的0.9～1.4倍,表明硫铵在水稻土中的转化效率略高于尿素.     

综合养鱼高产池塘的溶氧变化周期

根据1979—1984年对主养鲢、鳙、非鲫,主养青、草鱼,主养青鱼3种养殖结构类型高产鱼池溶氧变化周期的系统研究,揭示了高产养鱼池塘溶氧的昼夜、垂直、水平变化及季节变化周期,分析了光合作用、呼吸作用、扩散作用在高产养鱼池塘溶氧动力学上的地位和作用。对高产养鱼池塘的溶氧收入、支出及平衡情况进行了定量研究,在主要饲养季节,测得晴到多云天、晴天的溶氧来源分别为:浮游植物光合产氧占86.0和95.3%,大气扩散溶入占14.0和4.7%;氧的消耗分别为:“水呼吸”消耗氧占72.0和72.0%,鱼类呼吸消耗氧占22.0和13.1%,淤泥中生物呼吸消耗氧占2.9、5.5%,扩散逸出占3.1、8.8%。文中还对溶氧变化周期与养鱼池塘管理的环境控制、结构控制之间的关系进行了分析。       

北京西山不同人工林枯落物层的水化学性质

通过采集降雨经枯落物后的水样,初步研究了北京西山地区油松林和栓皮栎林林下枯落物层的水化学性质.结果表明:大气降水经过林冠进入枯落物层后,油松林和栓皮栎林林下不同元素的浓度发生明显变化.枯落物水中K 、Na 、Ca2 、Mg2 、NH4 -N和NO3--N的浓度随时间的变化趋势基本一致.穿透雨经过枯落物层后,水中K 、Na 、Ca2 和Mg2 的平均浓度增加,而NH4 -N、NO3--N的平均浓度减小.其中,栓皮栎林和油松林中Ca2 浓度分别增加了7.54和5.27mg.L-1.栓皮栎林下枯落物层中K 、Na 、Ca2 、Mg2 的平均浓度高于油松林,而NH4 -N、NO3--N的平均浓度则低于油松林;经降水淋溶作用后,栓皮栎林和油松林林下枯落物归还林地的养分分别为41.59和58.12kg.hm-2,其中归还林地较多的是Ca2 ,其次是K .     

Hydraulic loading,stability and water quality of Nakivubo wetland,Uganda

Nakivubo wetland, which has performed tertiary water treatment for Kampala city for the past 40 years, is ecologically stressed by agricultural and infrastructural developments. Field studies were carried out to assess the hydraulic loading, pollution profile, stability and water quality of this wetland. The upper and lower Nakivubo wetland receive 4.13?7.66 × 10⁴ and 3.50?10.32 × 10⁴m³/day of water respectively, of which 48.3–57.9% of total hydraulic loading to the upper wetland was carried by sampling station S1. The influent water to the upper wetland had a total BOD₅ and NH₄-N loading ranging from 2.6?4.4 × 10³kg BOD/day and 0.79?1.68 × 10³kg NH₄-N/day respectively. The National Water and Sewerage Corporation's effluent constituted a large proportion of BOD and NH₄-N loading into Nakivubo wetland. Zinc, copper and chromium were detected in trace amounts at most sampling stations. However, lead was occasionally detected at Kibira channel (station S5) at a concentration of 0.4mg/l, which is higher than the permitted Ugandan discharge limit of 0.1mg/l (NEMA 1999). The wetland showed a very high removal efficiency for BOD, ranging from 77.4%–86.3%, compared to ammonium-N which ranged from ?66.1% to 33.1% indicating limitations with the nitrification process. A low self-purification for zinc, copper and chromium was also observed in the upper Nakivubo wetland, possibly due to poor plant-wastewater interaction resulting from wetland drainage. In the lower Nakivubo wetland conductivity and dissolved oxygen were generally higher in papyrus- than in Miscanthidium-vegetated zones. However, the BOD and ammonium-N loadings did not vary significantly (P = 0.217 and P = 0.359 respectively) between the two vegetated zones.     

Inorganic and organic losses of nitrogen from upland regions of Britain: concentrations and fluxes

The nitrogen (N) composition of streams draining eight upland regions of Britain was compared using monthly samples collected between April 1997 and April 1998. Stream samples were analysed for total N (TN), particulate N (PN), nitrate (NO3), ammonium (NH4), and dissolved organic nitrogen (DON). Concentrations of TN were small, generally less than 1.5 mg N l(-1), were dominated by dissolved forms of N, and varied significantly between regions. NO3 accounted for the majority of variability. Concentrations of DON also varied between regions but to a smaller extent than those of NO3. There were considerable variations in TN fluxes between upland regions, which ranged between 3.8 and 16.1 kg N ha(-1) year(-1). The majority of the variation was due to NO3 fluxes, which were largest in regions receiving largest inputs of atmospheric N deposition and ranged between 1.4 and 13.5 kg N ha(-1) year(-1). Fluxes of DON ranged between 1 and 3.5 kg N ha(-1) year( -1), while fluxes of PN were generally less than 0.5 kg N ha(-1) year(-1) , and NH4 fluxes ranged between 0.1 and 0.4 kg N ha(-1) year(-1). NO3 was the dominant fraction (47-84%) of N exported from all upland regions except the Highlands, where DON accounted for 52% of the TN flux. This study has shown that the DON fraction is an important component of the total N transported by upland streams in Britain.     

太湖地区氮素湿沉降动态及生态学意义：以常熟生态站为例

在常熟生态站2001年6月至2003年5月连续两年定位收集湿沉降,对太湖地区氮素湿沉降动态进行研究．结果表明,湿沉降氮输入量季节变化显著,夏、春季高,秋、冬季低．在湿沉降输入氮中NH4^+-N、NO3^--N和DON的比例分别为47．6％、35．1％和17．4％．湿沉降中NH4^+-N主要来自当地农田的氨挥发,湿沉降NH4^+-N月输入量随月降雨量增加而增加(R0=0．3178^**)．该地区空气中NO3^--N浓度相对比较稳定,湿沉降中NO3^--N浓度与降雨量呈负相关(R^2=0．4205^***)．湿沉降NO33^--N月输入量与月降雨次数呈直线正相关(R^2=0．6757***),而与月降雨量相关性较差(R^2=0．1985^*)．湿沉降TN年输入量为27．0kg·hm^-2,并在所有降雨中,氮浓度均超过水体富营养化阈值(0．2mg·L^-1)．     

Role of aquatic vegetation coverage on hypoxia and sunfish abundance in bays of a eutrophic reservoir

We studied the relation between aquatic vegetation coverage, summer dissolved oxygen and density of sunfishes (Lepomis spp.) in 10 shallow bays of a eutrophic reservoir. The bays ranged 5.2–15.7 ha in area, 0.6–1.3 m mean depth and 6–91% vegetation area coverage. Over the 10 bays mean dissolved oxygen concentration ranged 5.8–9.0 mg l^-1 in open water at least 20 m away from the vegetation, 0.8–8.1 mg l^-1 at the vegetation-water edge and 0.5–7.7 mg l^-1 in dense vegetation. Dissolved oxygen concentrations were inversely related to vegetation coverage. In open water, dissolved oxygen levels were consistently higher than 8 mg l^-1 when vegetation coverage was <20% of the bay and decreased to about 6 mg l^-1 at coverages near 80%. At the vegetation-water edge and within dense vegetation, dissolved oxygen levels dropped rapidly as vegetation coverage increased to 20% of the bay; when vegetation reached about 50% coverage, dissolved oxygen remained near 1.5 mg l^-1at the vegetation-water edge, but oxygen dropped below 1 mg l^-1in dense vegetation. Scarce vegetation harbored high Lepomis relative abundance (fish per m² of vegetation) whereas extensive vegetation harbored low relative abundance, both contributing little to absolute abundance (total fish in all vegetation); however, intermediate coverage offered a combination of mid-level fish relative abundance that together with mid-level plant coverage translated into high absolute fish abundance. We suggest this response is related to hypoxia, and where aquatic vegetation is extensive, the effect of vegetation on hypoxia and water quality in general may influence fish populations in a way similar to that often attributed to reduced foraging efficiency and increased competitive interactions.     

Effects of aerial spray volume, coverage, and sabadilla on Scirtothrips perseae (Thysanoptera: Thripidae).

Helicopter applications using sabadilla (27-57 g [AI]/ha and 11.1-23.7 kg/ha sugar bait) in different volumes of water were made on avocado against Scirtothrips perseae Nakahara in Ventura County, CA. On small (2.8 m tall) trees, volumes of 374 and 795 liter/ha resulted in 3-18% and 19-43% spray coverage, respectively, on water-sensitive papers. On large (6.9-8.4 m tall) trees, these volumes resulted in only 1-3% and 6-11% coverage, respectively. On small trees, sabadilla in 374 liter/ha significantly reduced numbers of larvae 3 and 6 d after treatment (DAT). In contrast, on large trees, 374 liter/ha did not reduce larval numbers and was less effective than 561-1,964 liter/ha from 3-11 DAT. However, volumes of 1,543 and 1,964 liter/ha did not increase efficacy compared with 1,169 liter/ha. The results indicate that large trees require sabadilla in higher spray volumes for control of S. perseae, making applications on large trees more costly. The extra costs may not result in larval control beyond 11 d, making it especially critical to properly time applications on large trees.     

Preparation of ultra-lightweight sludge ceramics (ULSC) and application for pharmaceutical advanced wastewater treatment in a biological aerobic filter (BAF)

Novel media-ultra-lightweight sludge ceramics (ULSC) employed in an upflow lab-scale biological aerobic filter (BAF) were investigated for pharmaceutical advanced wastewater treatment. The influences of the volume ratio of pharmaceutical wastewater to domestic wastewater (PW/DW), hydraulic retention time (HRT) and air-liquid ratio (A/L) on chemical oxygen demand (CODCr) and ammonium (NH(4)(+)-N) of the effluent were investigated. When PW/DW of 4:1, HRT of 6 h, and A/L of 5:1 were applied, the mean effluent concentration of NH(4)(+)-N was 6.2 mg L(-1), and the maximum CODCr concentration in the effluent was 96 mg L(-1). Both NH(4)(+)-N and CODCr did not exceed the limits of the national discharge standards (NH(4)(+)-N ≤ 15 mg L(-1), CODCr ≤ 100 mg L(-1)). In addition, the BAF system showed a strong capacity of further removal from NH(4)(+)-N of the effluent.     

Enhanced removal of organic matter and ammoniacal-nitrogen in a column experiment of tidal flow constructed wetland system

A tidal flow constructed wetland system was investigated for the removal of organic matter and ammoniacal-nitrogen from diluted piggery wastewater. The results demonstrated that the operation of tidal flow enhanced the transfer of oxygen into wetland matrices. The supply of oxygen by the operation (473 gO2/m2d) matched the demand for wastewater treatment. The overall oxygen consumption rate in the system was considerably higher than the typical rate obtainable in conventional wetlands; most oxygen being used for the decomposition of organic matter. Compared with conventional systems, the tidal flow system demonstrated greater efficiency in the removal of organic matter. Significant nitrification did not take place, although 27-48% ammonia was removed from the wastewater. Immobilization by microbial cells and adsorption were the likely routes to remove ammonia under the specific experiment conditions. Percentage removals of BOD5, NH4-N and SS increased after effluent recirculation at a ratio of 1:1 was employed.