Vertical distribution and release characteristics of nitrogen fractions in sediments in the estuaries of Dianchi Lake,China

Columnar sediment samples were collected from five representative estuaries of Dianchi Lake, China. And the vertical distribution of each fraction of nitrogen (IEF-N, CF-N, IMOF-N, OSF-N) were tested. The results showed that the TN content in sediments from areas A, B, C, D and E gradually decreased with depth between 0 and 15 cm, then sharply decreased with depth between 15 and 30 cm and stabilized at depth below 30 cm, indicating the exogenous input of N in these areas has not been controlled effectively. The proportion of TN occupied by various N fractions in the sediments ranked as follows: OSF-N > IMOF > CF-N > IEF-N. Correlation analysis results showed both IEF-N and IMOF-N were significantly correlated with the content of TFe₂O₃ + MnO + Al₂O₃ in deeper sediments, while no correlation in superficial sediments. The areas A and B have extremely high release risks for N in superficial sediments. However, the N in the sediments of areas C, D and E were in relative equilibrium with the overlying water, indicating release potential risk was relatively low.     

岱海表层沉积物中内源磷的释放

以北方半干旱地区典型内陆封闭湖泊岱海为研究对象,开展了上覆水质及多种环境因子(温度,pH,溶解氧,扰动,光照)对湖泊沉积物内源磷释放的影响研究。结果表明:(1)温度升高有利于内源磷的释放,湖泊水体在温度较高的夏季更易呈现富营养化状态;(2)碱性条件有利于磷的释放,岱海水体属微碱性环境(pH8.8),若水体pH进一步升高,将会造成沉积物内源磷的大量释放;(3)厌氧条件(ρDO0.8mg/L)有利于磷的释放,岱海湖心区水深较深,易形成厌氧环境,因此湖心区内源磷释放强度较浅水区大;(4)强烈扰动有利于磷的释放,这会对浅水区的底质产生较大影响;(5)照度通过底栖藻类的生物作用,间接地限制了沉积物释磷对上覆水中磷浓度的影响。     

Influence of outbreak of macroalgal blooms on phosphorus release from the sediments in Swan Lake Wetland,China

Macroalgal blooms have occurred worldwide frequently in coastal areas in recent decades, which dramatically modify phosphorus (P) cycle in water column and the sediments. Rongcheng Swan Lake Wetland, a coastal wetland in China, is suffering from extensive macroalgal blooms. In order to verify the influence of macroalgal growth on sediment P release, the sediments and filamentous Chaetomorpha spp. were incubated in the laboratory to investigate the changes of water quality parameters, P levels in overlying water, and sediments during the growth period. In addition, algal biomass and tissue P concentration were determined. In general, Chaetomorpha biomasses were much higher in high P treatments than in low P treatments. Compared with algae+low P water treatment, the addition of sediments increased the algal growth rate and P accumulation amount. During the algal growth, water pH increased greatly, which showed significant correlation with algal biomass in treatments with high P (P < 0.05). P fractions in the sediments showed that Fe/Al–P and organic P concentrations declined during the algal growth, and great changes were observed in algae+low P water+sediment treatment for both. As a whole, the sediments can supply P for Chaetomorpha growth when water P level was low, and the probable mechanism was the release of Fe/Al–P at high pH condition induced by intensive Chaetomorpha blooms.     

Seasonal and spatial variations of heavy metals in surface sediments collected from the Baoxiang River in the Dianchi Watershed,China

To explore potential ecological hazards due to heavy metals in the Dianchi Lake Watershed, a three-stage European Community Bureau of Reference (BCR) sequential extraction procedure was applied to examine the spatial distributions and relative speciation ratios of Zn, Cu, Ni, Pb, and Cr in Baoxiang River sediments during wet and dry seasons. The metal species have similar spatial variations during different seasons. In the upstream reaches of the Baoxiang River, heavy metals reside primarily in the non-extractable residual fraction (72–90%). In the midstream, the residual fraction (35–89%) remains dominant, but the extractable fraction increases, featuring especially notable increases in the reducible fraction (5–40%). Downstream, the Cu, Ni, Pb, and Cr residual fractions remain high (46–80%) and the extractable fractions increase rapidly; the Zn extractable fraction is quite high (65.5%). Anthropogenic sources drive changes in heavy metal speciation. Changes in the river environment, such as pH and oxidation-reduction potential, also affect speciation. The reducible fraction of heavy metals in Baoxiang River sediments is most sensitive to pH. Potential ecological risk assessments for these five elements indicate that risks from Zn and Pb are mild to moderate in the middle and lower reaches of the river.     

有机磷农药对滇池微囊藻生长和摄磷效应的影响

采集滇池水体作为铜绿微囊藻培养基,研究了两种有机磷农药(甲胺磷和辛硫磷)对微囊藻生长和摄磷效应的动力学规律。结果表明,在滇池水体中添加较低浓度的甲胺磷(0.8、1.6、3.2mg/L)和辛硫磷(0.02、0.06、0.1mg/L)均能不同程度地促进微囊藻的生长,且在HGZ培养基中抑制微囊藻生长的浓度在滇池水体中却能促进微囊藻的生长。微囊藻的生长取决于细胞内磷的浓度且对磷的吸收利用存在积累性,在微囊藻生长初期,摄取各形态磷的速率较快;随后微囊藻摄取各形态磷的速率较慢。总溶解磷(TSP)和溶解反应磷(SRP)是微囊藻优先摄取的磷形态,在生长过程中微囊藻利用了大量的溶解有机磷(DOP)作为磷源加速生长。这一特点对于微囊藻成为淡水湖泊富营养化发展过程中的一种重要优势种具有极为重要的作用。     

Release of phosphorus from sediments in Lake Biwa

Two sulfur-mediated reactions are resulting in the eutrophication of Lake Biwa, Japan. The iron (II) phosphate mineral vivianite is dissolving in sulfide-enriched sediments that in places results in porewater concentrations of phosphate exceeding 3 mg l⁻¹. The dissolution of phosphate is evident in profiles of total phosphorus where zones of dissolution and a zone of precipitation in the most oxic surface sediments are visible. At times sulfate reduction in these surface sediments results in pH values as high as 9.9, which can dissolve phosphate adsorbed to iron (III). This release of phosphorus from sediments is at least partially responsible for the recent appearance of blue-green algal blooms. Received: August 4, 2000 / Accepted: March 19, 2001     

滇池微囊藻病毒溶藻的研究

微囊藻在养殖中有时会发生藻体溶解现象 ,其特征为藻体在生长旺盛期时如有病毒污染会迅速将藻体彻底溶解 ,由绿色变为清澈的淡黄色或无色透明状。此种病状尚无文献报道。因此 ,对此病状进行了分离及电镜观察和核酸分析。分离的噬藻体有 2种形态 ,一种呈蝌蚪型 ,具有多面体的头部和长而不收缩的长尾。头部 6 0 .9nm× 6 1.4nm ,尾部 2 88nm× 10nm。另一种头部呈多面体 ,尾部明显短 ,有 2个刺突状结构 ,头部5 6nm× 5 5nm ,尾部 15 6nm× 12nm。噬藻体核酸经酶解证明为DNA ,分子量均在 2 9.8× 10 6u。     

滇池土著鱼类现状

于2000年4月－12月对滇池区域的土著鱼类进行调查发现,滇池土著鱼类由20世纪60年代的26种减少到目前的11种,这11种滇池土著鱼类中,仅有4种生活于滇池湖体,其余7种均生活于滇池湖周一些溪流的上游或溶洞中,通过对土著鱼类及其栖息地的实地调查并结合文献资料,分析了滇池土著鱼类多样性的历史变化,各种类在空间上的变化方式以及滇池土著鱼类多样性迅速降低的原因,并就保护滇池土著鱼类提出具体的解决方法和途径。     

杭州西湖北里湖沉积物氮磷内源静态释放的季节变化及通量估算

通过采集北里湖不同季节的柱状芯样,在实验室静态模拟沉积物氨氮(NH+4-N)和可溶解性磷酸盐(PO3-4-P)的释放,同时研究了沉积物间隙水中NH+4-N及PO3-4-P的垂直分布特征.结果表明,沉积物间隙水NH+4-N随深度的增加有上升的趋势,PO3-4-P随深度的增加呈先升后降的趋势.氮、磷营养盐在沉积物—水界面均存在浓度梯度,表明存在自间隙水向上覆水扩散的趋势.沉积物NH+4-N在春季、夏季、秋季、冬季的释放速率分别为0.074 mg·m-2· d-1、0.340mg· m-2· d-1、0.087 mg· m-2· d-1、0.0004 mg·m-2·d-1,pO3-4-P的释放速率则分别为0.340 mg·m-2·d-1、0.518 mg·m-2·d-1、0.094 mg·m-2·d-1、-0.037 mg· m-2·d-1.不同采样点表现出明显的季节和空间差异性,释放速率表现为夏季＞春季、秋季＞冬季.根据静态模拟出的不同季节下内源氮、磷释放速率计算,全湖内源氮、磷营养盐的贡献分别为0.0037、0.0057t/a.该研究可为北里湖富营养化及内源污染的治理提供基础数据.     

Dissolved oxygen dependent phosphorus release from profundal sediments of Lake Constance (Obersee)

Phosphorus release rates from profundal sediments of Lake Constance (Obersee) have been determined in D.O., pH regulated sediment-water systems. Above 10% O₂ saturation (> 1.2 ppm D. O.) and with pH as in situ, no net release could be found. Sedimentations of diatom sludge (Asterionella formosa) and carbonate-phosphate coprecipitate (CaCO₃.CaHPO₄) increased the release to 0.5 mg × m^–2 × d^–1 which, however, will not be relevant to the P balance in Obersee. The annual phosphorus accumulation in profundal Obersee and Ueberlingersee is, therefore, observed as due to sinking of phosphorus-bound detritus during the stagnation period.The experimental work was carried out at the Limnological Institute of the University of Freiburg/Breisgau (West Germany) and has been supported by the Industrieverband Körperpflege und Waschmittel e.V. and the Gernan Research Council (DFG)The experimental work was carried out at the Limnological Institute of the University of Freiburg/Breisgau (West Germany) and has been supported by the Industrieverband Körperpflege und Waschmittel e.V. and the Gernan Research Council (DFG)     

云南滇池富磷区趋化性细菌的系统多样性

从云南滇池富磷区100份土样中筛选解磷细菌(PSB),通过组氨酸激酶编码基因(cheA)筛选趋化性PSB,并通过软琼脂平板法验证其趋化性;利用钼蓝比色法测定PSB对磷酸三钙的溶解能力;基于16S rRNA基因序列分析趋化性PSB的系统亲缘关系.结果表明： 分离到的145株PSB的溶磷圈直径在0.5～2 cm,其中37株为趋化性PSB.该37株PSB对供试的4种趋化底物均具有趋化性,而且对磷酸三钙均具有解磷活性.基于16S rRNA基因序列的系统发育分析显示,这37株趋化性PSB分属于10属,共17种细菌,其中假单胞菌属种类最多(5种9株),肠杆菌属次之(3种8株),芽孢杆菌属尽管只分离到1个种(Bacillus aryabhattai),但共分离到9个菌株.     

太湖春季沉积物间隙水中磷的分布特征及界面释放的影响

通过对太湖春季不同湖区水体和沉积物间隙水中磷的分布特征研究,探讨了间隙水中磷的释放对上覆水环境的影响。结果表明,颗粒态磷(PP)和溶解态有机磷(DOP)是太湖水体中主要的磷形态,占总磷的58%～95%。不同湖区沉积物间隙水磷的剖面变化可能与生态特征及水动力引起的沉积物-水界面的扰动强度密切相关。湖心和西部沿岸沉积物扰动强烈,致使间隙水中磷含量向上逐渐降底,而梅梁湾和贡湖间隙水磷的垂向变化不大。东太湖和竺山湖沉积物界面间隙水中磷含量偏高,可能是由于表层沉积物的有氧环境使Fe2+被氧化固定下来,并促进了总磷(TP)和溶解态活性磷(DRP)的扩散释放。总体而言,间隙水中各形态磷具有向上覆水体释放的趋势,其中DRP的扩散潜力最大,竺山湖沉积物-水界面DRP扩散通量高达11.42mg.m-2.d-1,表明春季浮游植物的复苏生长对DRP的迫切需求。     

小型浅水湖泊沉积物磷的赋存形态及其相关性分析

以孔目湖沉积物为研究对象, 应用七步连续提取法测定其中的不同形态磷, 探讨了该湖泊沉积物中各赋存形态磷的分布特征, 并对其进行了相关性分析。结果表明: 该湖泊遭受的磷内源负荷比较大, 磷污染严重; 沉积物中TP含量在2338.63-2954.98 mg•kg-1, 平均为2671.37 mg•kg-1; 沉积物中各形态磷含量从高到低依次为: Fe-P>De-P>Ca-P> OP>Al-P>Oc-P>Ex-P, 分别占TP的53.9%、28.7%、8.8%、6.2%、1.2%、0.9%、0.3%; 生物有效磷含量为1583.59 mg•kg-1, 占TP的59.28%; 沉积物中TP与Fe-P极显著相关, Oc-P与Ca-P和OP与Ca-P均相关, 而TP与Ex-P、Al-P、Ca-P和OP相关性较差, 说明沉积物中TP含量主要来自于Fe-P。这一研究结果为揭示小型湖泊富营养化发生机制提供了数据及理论支撑。     

大理西湖流域开发历史与硅藻群落变化的模式识别

有关云南湖泊的研究长期集中于高原九大湖泊和水体富营养化评价,缺少对中小型水体及多重环境压力胁迫的综合研究.本文以大理西湖为例,结合沉积物记录与现代监测资料,甄别了气候变化和人类活动干扰下硅藻群落结构的长期响应模式及其驱动强度.结果表明: 20世纪50年代以前,大理西湖总体处于自然演化阶段;1950年代开始,围湖造田和流域改造的增强导致了水体营养水平增加、水动力条件改变,硅藻优势种由扁圆卵型藻替代为脆杆藻属;而1997年以来营养水平的快速增加和湖泊水动力的改变,促进了浮游藻类大量生长、底栖硅藻持续减少,同时水生植物快速退化、生态系统稳定性明显降低.因此,在长期流域开发的背景下,对云南中小型高山湖泊的有效保护需要评价流域开发类型、强度及全球变暖的长期影响.     

Stratification of alkaline phosphatase in sediments of two urban lakes and its effect on phosphorus cycle

Phosphorus loadings in sediments play an important role in lake eutrophication and the progress of its recovery. The phosphorus release is controlled by physical, chemical and biological mechanisms. Alkaline phosphatase catalyzes remineralization of organic phosphorus and then it may be an important factor accelerating phosphorus cycling in sediments. In this paper, distributions, properties and function of alkaline phosphatase with depths in sediments of two urban lakes were discussed. Alkaline phosphatase activity (APA) in the sediments of Lake Yuehu decreased with the sediment depth. APA in sediments of Lake Yuehu was, mostly, inhibited by Phe and L-Cys; and inhibiting ability of Phe could be stronger than L-Cys. APA in deeper layer (20–30 cm) of sediments was more sensitive to the inhibitors than other layers, but range of variation in APA was most wide in the subsurface layer (10–20 cm). All the facts implied that alkaline phosphatase occurred in various forms (isoenzymes). APA in the sediments with different depths of Lake Donghu responded Phe differently. Reacted with Phe and incubated for 1 day, the amounts of SRP released by these sediments varied correspondingly. SRP on the overlying water in deeper layers (5–10 cm and 15–20 cm) of Site T1 was higher than that in surface layer (0–5 cm) of the same site, 1 day after incubation. Hence, the SRP release resulted, at least partially, from the hydrolysis of some liable organic phosphorus mediated by APA. Alkaline phosphatase in lake sediments plays an important role in the release of internal phosphorus loadings and eutrophication. A possible explanation for the sensitivity at deeper layers could be another active region of hydrolysis by alkaline phosphatase from organic phosphorus, which added a new dimension in phosphorus cycling mediated by some biochemical mechanisms.     

阳宗海和滇池中紫色非硫细菌数量和种群结构的比较

在2002年平水期对高原湖泊阳宗海和滇池中的紫色非硫细菌(PNSB)数量和种群结构进行了比较研究。对两湖中的各因子进行t检验,发现各因子和PNSB数量都有极显著差异,富营养化湖泊滇池中的PNSB数量远远多于贫营养化湖泊阳宗海;两湖中PNSB的优势种是红假单胞菌属,也有少数的红螺菌属。两湖种群结构的区别是滇池有红微菌,而阳宗海有大量红细菌。     

黄东海陆架区沉积物中磷的形态分布及生物可利用性

采用1992年Ruttenberg连续提取法(SEDEX)将黄东海陆架区沉积物中的磷分为交换态磷(Ex-P),Fe结合态磷(Fe-P),自生磷(Au-P),碎屑磷(De-P),有机磷(Or-P),分析了各形态磷的平面和垂直分布特征;利用沉积物年代序列测定的结果,探讨了柱状沉积物中不同形态磷的含量变化,并进一步分析了该区域磷形态的生物可利用性.结果表明,黄东海陆架区表层沉积物各形态磷平均含量为:Au-P(140.72 μg/g)＞De-P(59.23 μg/g)＞Or-P(32.69 μg/g)＞Fe-P(29.91 μg/g)＞Ex-P(5.92 μg/g);各形态磷在沉积时间序列上分布不同,反映了不同时期人类活动和气候环境等因子对磷埋藏量影响的不同,其中Au-P在长江口H1-18站位含量比南黄海中部3个站位要低得多;调查区表层潜在生物有效磷为13.55％左右,仅仅占沉积磷中的一小部分.     

滇池外海蓝藻水华爆发反演及规律探讨

气象条件和营养盐浓度一直被认为是导致蓝藻水华爆发的两个重要因素。通过滇池外海Chla浓度时空分异性分析,得出晖湾中测点最易爆发蓝藻水华且爆发时间集中在每年6—9月。同时,采用基于缺失数据多重插补的EMB算法将气象条件和蓝藻水华爆发的不完全数据集进行反演,建立了滇池外海2004—2008年4—10月完整的气象、营养盐及蓝藻爆发的基础数据集,解决了表观蓝藻水华爆发研究中观测数据缺失的问题。据此,探讨了滇池外海晖湾中测点Chla、TN和TP与蓝藻水华爆发关系,进而提出了控制滇池外海蓝藻水华的一种新思路。     

Mobility of phosphorus fractions in the sediments of Lake Balaton

Sediment phosporus was studied by a combination of the fractionation procedure of Hieltjes & Lijklema and the isotopic dilution technique in a mesotrophic (Tihany) and a hypertrophic (Keszthely) basin of Lake Balaton.In the calcareous sediments the largest part of phosphorus was bound to calcium. Iron-bound and residual P showed higher concentrations at Keszthely than at Tihany. There was little loosely adsorbed P at both locations. Vertical differences in P fractions of the sediments were more pronounced at Keszthely than at Tihany. Exchangeability of the fractions decreased in the following sequence: iron-bound > loosely adsorbed > calcium-bound > residual. Phosphorus, particularly in the calcium-bound fraction, was more mobile at Keszthely, and its exchangeability decreased rapidly downwards at both stations. Four times more potentially mobile phosphorus has been accumulated by the upper sediment layer at Keszthely than at Tihany.     

Effect of ecological engineering on the nutrient content of surface sediments in Lake Taihu, China

Ecological engineering was carried out in Meiliang Bay of Lake Taihu beginning in 2003 in order to improve water quality. There were two main objectives: to improve the growth environment for macrophytes, and to restore macrophyte assemblages. We examined surface sediments once per month beginning in April 2005 to study the response of sediment nutrient content to the ecological engineering. Average total nitrogen (TN) and total phosphorus (TP) concentrations in the surface sediments were 7043 and 1370 mg kg⁻¹, respectively, in May 2005, while after 1 year, TN concentration was reduced to 2929 mg kg⁻¹ and TP concentration was reduced to 352 mg kg⁻¹. We conclude that ecological engineering can lower the nutrient content in surface sediments when it is used to improve water quality.