洪湖湿地水生植被恢复技术要点

水生植被作为水生态系统的重要组成部分,具有净化水质、消减风浪、景观美化、提供水生生物栖息空间等多种功能.水生植被恢复是湖泊水生态保护与修复的关键环节.洪湖湿地是国际重要湿地,发挥着重要的生态功能,由于近半个世纪过度开展围网养殖等不合理的开发利用,水生植被大幅减少,降低了湖泊的自净能力,水生态系统遭到破坏.近几年,洪湖持...     

环境因子及沉水植物对底泥磷释放的影响研究

通过环境因子（温度、pH、扰动、溶解氧等）及沉水植物对底泥磷释放影响的研究，分析了环境因子影响底泥磷释放的因素，及不同环境条件下沉水植物影响底泥磷释放的因素，得出了如下结论：溶解氧、pH、温度及扰动等对底泥磷向上覆水体释放都有一定影响，其中溶解氧和pH值影响较大；湖泊特别浅水型湖泊中，磷对水体富营养化起重要作用；沉水植物在控制湖泊底泥营养向水体扩散、风等外界因素扰动底泥起关键作用；浅水型湖泊中，湖泊底泥受扰动较大适合种植象狐尾藻类多分枝的沉水植物，这样有利于抑制底泥磷向水体的释放．     

蔬菜地土壤磷饱和度及其对磷释放和水质的影响

为了解蔬菜地土壤磷素的积累对水环境的影响,我们在浙江省选择了33个代表性蔬菜地,采集和分析了土壤、地表水和地下水样的磷素状况,从土壤磷饱和度的角度,研究了浙江省主要蔬菜土壤磷积累状况及其对地表和地下水水质和土壤磷释放潜力的影响。结果表明,半透膜渗析法测得的磷释放量与土壤磷积累呈正相关,磷释放量随土壤磷饱和度的提高而增加。蔬菜地土壤磷饱和度的增加可显著提高地表水体和地下水中磷的浓度,当土壤磷饱和度小于25%左右时,水体中磷浓度随土壤磷饱和度增加较为缓慢;但当磷饱和度大于25%时,水体中磷浓度随土壤磷饱和度提高迅速上升。地表水中磷浓度主要与表层土壤磷饱和度有关;地下水中磷浓度主要受深层土壤磷饱和度的影响,与表层土壤磷饱和度的相关性较小。土壤磷饱和度可很好地表征土壤磷释放和对环境的潜在影响。     

影响富营养化湖泊底泥氮、磷释放的因素

[目的]分析水体酸碱度、温度以及上覆水营养盐浓度,为合理评估环境因素对湖泊底泥氮、磷释放的影响提供科学依据。[方法]选择富营氧化比较严重的云南省昆明市城市景观湖泊翠湖为研究区域,通过控制不同pH值、温度和上覆水营养盐浓度来模拟影响底泥氮磷释放的因素。[结果](1)放置时间相同条件下底泥氮、磷释放量受到水体酸碱性的影响,中性环境下(pH=7.5)释放量高于酸性和碱性水体条件。底泥释放5,10h条件下,pH值为7.5时底泥磷释放量分别达到5.88,8.28mg/kg;pH值为7.5时底泥氮释放量分别达到22.8,38.4mg/kg;(2)底泥氮、磷释放量随着温度升高而增加。温度为20℃时底泥氮、磷的释放量分别达到28.62,3.75mg/kg;(3)底泥氮、磷的释放量均随着上覆水浓度增加而减少,随着放置时间延长而增加。放置时间5h上覆水氨氮浓度0.31mg/L底泥氮的释放量最大,达到21.63mg/kg。放置10h在氨氮为2.37mg/L时底泥氮的释放量达到最大值(39.22mg/kg);底泥磷释放量在上覆水磷浓度0.14mg/L时底泥总磷的释放量最大;放置时间为5,10h时分别达到4.25,4.91mg/kg。[结论]底泥中营养盐释放是一相当复杂的动态过程,水体酸碱度、温度或上覆水营养盐浓度是影响释放量的主要因素。     

底泥疏浚对磷形态和磷释放的影响

A laboratory experiment was carried out through a six-month incubation of undredged （control） and dredged cores to study the effect of sediment dredging on phosphorus （P） release from the sediment in the Taihu Lake. During the experiment, dredging the upper 30 cm layer could efficiently reduce the interstitial PO4^3-P concentration and different P forms in the sediment. The P fluxes of the undredged and dredged cores ranged from -5.1 to 3047.6 and -60.7 to 14.4μg·m^-2·d^-1, respectively. The fluxes of the dredged cores were generally lower than those of the control. Differences in the fluxes between the dredged and undredged cores were statistically significant （P 〈 0.05） from March to June 2006. The sediment P in the dredged cores had a lower release potential than that in the control. Dredging can be considered as a useful measure for rehabilitating the aquatic ecosystem after the external P loading in the Talhu Lake catchment was efficiently reduced.     

咸潮对重污染底泥中重金属释放的影响

为了评估成潮对重污染河涌底泥重金属释放的影响,研究了底泥中的重金属在不同稀释倍数的人工海水中的释放,比较了海水中的主要离子对重金属释放的作用,并用BCR连续提取法比较了人工海水处理前后重金属形态变化.结果表明,底泥中重金属释放量随人工海水盐度的增加而增加.由于盐度的增加,Cu、Zn和Ni的释放量分别可增加1.5倍、0.88倍和1.1倍.与Na+相比,Mg2+具有很强的促进底泥重金属释放的能力.SO42-比Cl-稍强.经人工海水处理,重金属的弱酸提取态大部分转化为可还原态和可氧化态.残渣态变化较少.     

pH值对黄河兰州段底泥中总磷释放的影响

分析了不同pH值对黄河兰州段底泥总磷(TP)释放特性的影响。结果表明:底泥中的总磷在酸性范围内呈现负释放状态,且pH值越小",负释放强度越大";在碱性范围内,pH值越大,总磷释放量越大。当pH值为4和6时,水体中的总磷在第1 d都是下降,呈现出负释放的状态;pH值为4时,在第4 d负释放量达到最大值,而pH值为6时到实验结束时负释放量依然在增大。当pH值为10、11、12时,总磷呈现出明显的正释放状态,且在第2 d,总磷的释放量达到最大值。实验数据说明在碱性条件下,底泥中的磷对水质可能产生不良的影响。本次实验对黄河水质的监测以及治理有一定的参考价值。     

环境条件变化对滇池沉积物磷释放的影响

在实验室控制条件下,以滇池表层新鲜沉积物和湖水为材料,研究了氧化还原状况、水体扰动、pH值等环境因子对沉积物P释放的影响。结果表明,与好氧条件相比,厌氧状态大大促进沉积物中P的释放,最大释放量为3.96mg。随着湖水pH值的升高,沉积物的释P量明显增加,碱性条件下P释放量是中性条件的几百倍。水体扰动对沉积物P释放的影响不大。不同环境因子相比,湖水在碱性条件下(pH10.5)P的释放速率最大,高达68.04mg/(m2·d),厌氧条件次之,变化在7.73~8.91mg/(m2·d),对照和扰动条件下P释放速率很低。湖水pH值增加和氧化还原电位降低是滇池沉积物释P的主要机制。     

环境条件变化对瓦埠湖沉积物磷释放的影响

拟议中的“引江济淮”调水工程涉及到长江、淮河两大河流，瓦埠湖为其中的一个重要湖泊，其水质是否受到调水的影响为该工翟关注的环境问题之一。分析了外界环境因子变化对瓦埠湖底泥在不同环境条件下以及干、湿沉积物样品磷释放的差异，环境因子分别选取了不同磷浓度的上覆水、光照、pH、温度、DO、微生物、水体扰动等。结果表明：湿样释磷能力明显高于风干样品；上覆水体磷的浓度对底泥释磷能力有较强的调节作用；光照对底泥释磷影响不明显，但温度对底泥的释磷有较明显的影响，磷的最大释放量与之呈正相关；水动力条件的改变可在短期内使底泥达到最高的释放量．而DO、pH的改变也可不同程度地增加底泥的释磷能力。综合瓦埠湖底泥的释磷特征与湖泊水文状况，认为调水工程使得底泥释磷的地球化学行为较易实现。     

低分子量有机酸对土壤磷释放动力学的影响

模拟植物在缺磷条件下,根系所分泌的有机酸种类和数量,用流动法研究了柠檬酸,苹果酸,草酸和酒石酸对土壤磷释放的影响。结果表明：有机酸能明显促进土壤中磷的释放,不同有机酸对石灰性土壤活化能力大小的次序为草酸≥柠檬酸〉苹果酸〉酒石酸;而对酸性土壤磷的释放量与Ｆｅ＋Ａｌ释放量之间呈极 相关,有机酸活化土壤磷能力大小的次序为柠檬酸〉草酸〉酒石酸〉苹果酸。     

东平湖表层沉积物中磷的吸附容量及潜在释放风险分析

利用沉积物磷吸附指数（PSI）和磷吸附饱和度（DPS）研究了东平湖表层沉积物的磷吸附容量,并讨论了沉积物中磷的潜在释放风险。结果表明,表层沉积物的磷吸附指数变化范围为30.3～45.2[mg P·（100g）-1]·（μmol·L-1）-1,表现出从湖心、湖东向湖北、湖南逐渐增大的扇形特征;而磷吸附饱和度变化范围为6.5%～24.1%,与磷吸附指数变化趋势恰好相反。磷吸附指数与沉积物中草酸铵提取的铁（FeOX）含量呈极显著正相关,与草酸铵提取的铁铝总量呈显著正相关,磷吸附饱和度与沉积物中草酸铵提取的磷（POX）含量呈显著正相关。此外,磷释放风险指数（ERI）变化范围为14.9%～67.5%,表明东平湖表层沉积物中磷释放诱发富营养化的风险处于高度风险范围。     

10种水生植物的氮磷吸收和水质净化能力比较研究

选取10种水生植物水罂粟、黄花水龙、大聚藻、香菇草、水芹、大薸、凤眼莲、美人蕉、黄菖蒲和鸢尾等为研究对象,于2009年2月中旬至6月中旬在室内静水条件下对其吸收氮、磷和净化水质的能力进行了比较研究。结果表明：（1）不同水生植物的净增生物量差异较大,变化范围为109.9-1 511.1 g.m-2,其中香菇草净增生物量最高,是黄花水龙（最低）的13.7倍;（2）不同水生植物的氮、磷含量差异较小,其氮、磷量变化范围分别为13.67~26.38 mg.g-1和1.16~3.50 mg.g-1;（3）不同水生植物的水质净化能力差异较大,10种水生植物的水质氮、磷去除率范围分别为36.3%~91.8%和23.2%~94.0%,10种水生植物的氮、磷吸收贡献率分别占水质氮、磷去除率的46.3%~77.0%和54.3%~92.7%。水体氮、磷去除率与水生植物净增生物量存在较高相关性,而与植株氮、磷含量不存在相关性,因而氮、磷吸收量而不是植株氮、磷含量应作为水生植物筛选的一个重要指标。     

Long-Term Effects of Tillage and Manure Applications on Soil Phosphorus Fractions

Application of manure on the basis of crop nitrogen (N) need increases the level of soil phosphorus (P), which is concern for deterioration of surface water quality. Soil samples were collected from a long-term field study to investigate the impact of crop N need–based manure application on soil P fractions and P adsorption and release kinetics. The field experiment was initiated in 1990. The soil was moderately well-drained Kennebec (fine silty, mixed, mesic Cumulic Hapludolls). No-tillage (NT) and conventional-tillage (CT) treatments were established in main plots, and subplots had five N treatments, including a control, and annual application of 84 or 168 kg N ha^?1 applied as ammonium nitrate (NH₄NO₃) or beef (Bos taurus) manure. Manure at the high N application rate had significantly greater Bray 1 P under NT than under CT at 0- to 5-cm soil depth. Nitrogen fertilizer treatments were not significantly different than the control for Bray 1 P. Continuous application of manure at the high N rate significantly increased all Hedley P fractions; however, the major increase was observed in high bioavailable P pools [iron oxide (FeO) P and sodium bicarbonate (NaHCO₃) P_i] and hydrochloric acid (HCl) P fractions. Soil organic P (P_o) pools, including both labile (NaHCO₃-P_o) and resistant [sodium hydroxide (NaOH) P_o], were increased by application of N from any source, suggesting biomass production and return of residue to soil surface was the responsible factor. Continuous application of manure based on N need also significantly increased FeO-P, NaHCO₃-P_i, and HCl-P fractions at lower soil depths (5–15 and 15–30 cm). Results from the P-adsorption study suggest that ability of soil to adsorb additional P was decreased by manure application and that EPC₀ was increased. Maximum desorbable P was observed for manure treatments under NT, although the release constant k (h^?1) was significantly less than with fertilizer N treatments.     

Phosphorus Availability and Transformation as Affected by Repeated Phosphorus Additions in an Ultisol

Phosphorus (P) solubility and transformation in soils determine its availability to plants and loss potential to the environment, and soil P dynamics is impacted by fertilization and soil properties. A Ultisol sample was interacted with 20 mg L^?1 P solution from one to ten times. The P-reacted soils were then analyzed for water-soluble P (0.01 M calcium chloride (CaCl₂)–extractable P); plant-available P (Olsen P); ammonium chloride P, aluminum P, iron P (NH₄Cl-P, Al-P, Fe-P, respectively); and occluded P (Oc-P). The degree of P saturation (DPS) was calculated from ammonium oxalate–extractable Al, Fe, and P. The amount of P sorbed by the soil was highly correlated with the frequency of P addition with high percentage of P adsorbed initially and gradually decreased as the P addition continued. The relative abundance of the five P fractions in the P-reacted soil was in the order of Fe-P (36.5 percent) > Al-P (35.6 percent) > Oc-P (22.8 percent) > Ca-P (2.7 percent) > NH₄Cl-P (2.3 percent). Both Olsen P and CaCl₂-P were significantly increased by the repeated P addition process and highly correlated in an exponential function. The DPS was increased above the so-called critical point of 25 percent after the first P saturation process and kept increasing as the P addition continued. The P availability and adsorption in the soil were controlled by soil free and amorphous Al and Fe. The results suggest that repeated P application will build soil P to an excessive level, and consequently result in poor P-use efficiency and high P-loss potential to surface and groundwater.     

哈素海表层沉积物中内源磷的释放研究

以浅水湖泊哈素海为研究对象,开展了上覆水质、温度、pH、溶解氧、扰动和光照等环境要素对湖泊沉积物内源磷释放的影响试验研究。结果表明,温度升高、碱性条件、厌氧和强烈的扰动作用等均有利于内源磷的释放,而照度则间接地限制了沉积物释磷对上覆水中磷浓度的影响。HSH-2、HSH-5和HSH-6等3个站位TP的最大释放量在自然光照条件下分别为1.53、1.39和1.27 mg·kg^-1,避光条件下分别为1.77、1.52和1.52 mg·kg^-1;静置条件下分别为1.42、1.38和1.68 mg·kg^-1,R=60 r·min^-1时分别为1.75、1.50和2.00 mg·kg^-1,R=120 r·min^-1时分别为2.52、2.64和4.02 mg·kg^-1;在pH=11时释放量最大,分别为10.82、6.83和16.68 mg·kg^-1。各环境因子中,以pH和扰动对哈素海沉积物内源磷的释放影响最大。哈素海为浅水湖泊,在湖水咸化程度逐渐增高的条件下,将会导致湖泊沉积物内源磷的大量释放,从而将进一步加剧水体的富营养化。     

刚毛藻分解对荣成天鹅湖沉积物磷释放的影响

在荣成天鹅湖刚毛藻暴发和非暴发区域分别采集沉积物进行室内加藻模拟试验,定期监测上覆水的溶解氧（DO）、pH、化学需氧量（COD）和可溶性磷（SRP）等指标的变化,并分析了刚毛藻分解对沉积物磷释放的影响。结果表明,避光培养过程中,刚毛藻分解使上覆水体的DO含量大幅降低,形成厌氧环境（0~0.14 mg.L-1）;COD含量则明显增加,各处理最大值变化在0.59~6.93 mg.L-1之间。刚毛藻分解可明显促进沉积物中磷的释放,培养期间上覆水SRP的含量大幅上升,变幅为0.01~1.51 mg.L-1;暴发区沉积物＋10 g藻和沉积物＋30 g藻处理的最大释磷量分别为沉积物处理的2.06倍和1.91倍。不同湖区沉积物磷的释放能力存在较大差异,暴发区沉积物的释磷量明显高于非暴发区,沉积物释放是前者上覆水磷含量增加的主要来源,而在非暴发区藻类分解释放的磷高于沉积物中释放的磷。     

千岛湖水体生态风险胁迫因子氮、磷预测模型应用研究

引起水体富营养化的限制因子主要是氮和磷。现有的研究表明，干岛湖水体中TN浓度较高，已达到导致水体富营养化的危险程度，磷是干岛湖水体富营养化的限制因子。因此模拟和预测干岛湖水体中氮、磷的变化对指导干岛湖生态风险管理具有重要意义。建立了干岛湖氮、磷预测模型，通过对干岛湖水体总氮和总磷预测模型的预测结果进行检验，结果表明所构建模型应用于近期干岛湖总氮和总磷的模拟有较好的预测精度。因此，通过对干岛湖水质参数构建数学模型，模拟其水质变化过程，为科学评估干岛湖水质下降风险提供参考依据在理论上是完全可行的。根据氮、磷预测模型的运算结果显示，干岛湖全湖总氮与总磷的平均比值将持续维持在35～40：1范围内，进一步肯定了总磷仍然是干岛湖总体水质下降及富营养化的限制因子，其对于流域内总磷输入的防控管理是整个水体系统功能维持稳定状态的关键。     

石灰性土壤磷素的化学活化途径探讨

用草酸、草酸钠、柠檬酸和柠檬酸钠作为活化剂，加人不同含磷水平土壤中，通过室内培养试验和分析，结果表明：(1)0．1M草酸和0．1M柠檬酸都有一定的活化土壤磷素的作用，草酸作用最为显著。而相同浓度的草酸钠和柠檬酸钠未显示对土壤磷素的活化效果。(2)对土壤磷素的活化作用，草酸随其浓度的增加而增强，而柠檬酸活化土壤磷的能力有限。(3)柠檬酸在加人的6h之内，对活化土壤速效磷作用明显；而草酸在加人的48h之内，对活化土壤速效磷有十分显著的作用。无论是柠檬酸还是草酸，在其对土壤速效磷发挥活化作用期间，均随加人时间的延长而减弱。     

Effect of Coal Combustion By-products on Phosphorus Runoff from a Coastal Plain Soil

Coal combustion by-products can lower soil phosphorus (P) solubility, but few studies have assessed their effect on runoff P. A soil with elevated P content was amended with fluidized bed combustion ash, flue gas desulfurization gypsum, and anthracite refuse ash at rates of 0–40 g kg^?1 soil, and runoff from small plots was monitored over 3 years. In the first year, by-products lowered dissolved P in runoff by up to 47% below the untreated control; however, effects did not persist into the remaining years of the study. Total P losses were not significantly affected by coal combustion by-products, likely because of elevated particulate P losses. Water-extractable P was up to 40% less in treated soils than in untreated soils across the 3 years. Results demonstrate that although coal combustion by-products readily lower P solubility in soils, their impact on P losses in runoff can be undermined by erosional processes.