净化湖泊水体氮污染的固定化硝化-反硝化菌研究

依据太湖水体氮污染的特点,设计应用低温辐射技术引导玻璃态单体丙烯酸羟乙脂－２－Ｈｙｄｒｏｘｙｅｔｈｙｌ ａｃｒｙｌａｔｅ（ＨＥＡ）与聚乙二醇二甲基丙烯酸酯Ｐｏｌｙｅｔｈｙｌｅｎｅ ｇｌｙｃｏｌ ｄｉｍｅｔｈａｃｒｙｌａｔｅ（１４Ｇ）制备高分子载体,并使用增殖细胞技术固定化硝化－反硝化菌净化湖水。研究结果表明,富营养化湖水经过固定化硝化－反硝化菌ＳＢＲ工艺净化后,总氮下降７０％,氨氮下降８４％,ＣＯ     

风浪扰动对太湖水体悬浮物重金属含量的影响

通过离心浓缩的方法,获取太湖梅梁湾口东岸处(即梅梁湾与贡湖湾的交界处)不同风浪条件下的悬浮颗粒物．冷冻干燥,微波消解,ICP-AES的方法测定了其中Co、Cr、Cu、Ni、Pb、Zn等重金属元素及Al、Ca、Fe、Mn等相关金属元素的含量．结果发现,小风浪(2 m/s)、中风浪(7 m/s)和大风浪(11 m/s)下：①水体总悬浮颗粒态金属的量依次大幅度增加;②单位悬浮颗粒物中各金属元素的含量在不同风浪下变化不同．Ca在小、中、大风浪下含量依次增大;Zn在小、中、大风浪下含量依次减少;Mn和Cu的含量变化趋势相同：与小风浪相比,中风浪下Mn、Cu的含量显著增大;与中风浪相比,大风浪下含量显著减少;其它元素Al、Fe、Ni、Pb、Co、Cr等在单位悬浮物中,中风浪与小风浪相比含量减少,大风浪与中风浪相比含量略微增加．研究表明：①金属元素在水体总悬浮物中的含量主要受风浪影响,但风浪对单位悬浮物中金属含量的影响则因元素而异;②除Cu、Mn、Zn外,悬浮物中重金属含量随粒径增大含量减少．     

太湖水体中悬浮物的静沉降特征

本文分别采用斯托克斯沉降速率公式和重复深度吸管法计算了2005年4月、5月间在太湖进行的四次静沉降模拟实验中的沉降速度．结果表明：1)太湖水体中悬浮物的沉降属于絮凝沉降．2)水体中悬浮物浓度与沉降时间均呈现出明显的指数衰减规律(R~2＞0．80),悬浮物中无机物含量较高时这种规律更为明显(R~2≥0．99)．3)悬浮物浓较低时,太湖悬浮物的沉降速率与水体中的悬浮物浓度无明显的相关关系;而悬浮物浓度较高时,沉降速率随悬浮物浓度升高而增大．经拟合沉降速度(ω)与悬浮物浓度(C)之间符合Logistic曲线ω=0．021/(1 exp(-0．026(C-166．3))),R~2=0．98,n=54．4),斯托克斯公式可用来粗略估算太湖悬浮物的沉降速率,而重复深度吸管法则适合于较精确地计算太湖悬浮物的沉降速率．但在计算时须注意根据悬浮物的特性,选取其特征沉降速率．本文计算得到的太湖悬浮物的沉降速率范围为0．002 cm/s-0．005 cm/s．     

污染水体中悬浮物对菹草(Potamageton crispus)生长的影响

以菹草（Potamageton crispus）为对象,通过对植物鲜重、叶绿素含量、净产氧量、过氧化物酶（POD）和过氧化氢酶（CAT）活性的观测,研究了悬浮物附着对沉水植物生理生化作用的影响．结果表明,在苏州苗家河重污染水体中,高负荷的悬浮物对菹草的生长产生重大影响．实验25d,有悬浮物附着的菹草的生物量仅为对照样的63．93％,叶绿素含量及叶绿素a／b值仅为对照样的66．24％和63．88％;植物体内的过氧化物酶活性及过氧化氢酶活性也呈现下降趋势,分别为对照样的61．25％和40．30％．悬浮物是重建沉水植物的重要限制因素之一．     

太湖流域滆湖水体悬浮物分布特征及其影响因素

基于2018—2019年的周年调查,分析了滆湖总悬浮物（TSS）的时空分布特征、组成及其季节变化规律,并探讨了水体悬浮物的影响因素及其与氮、磷的关系.结果表明：（1） TSS浓度的年内变化范围在11.80~105.87 mg/L之间,平均浓度为41.87±18.09 mg/L.（2）滆湖水体TSS时空差异显著.空间上呈现高速公路以南湖区（B区）大于高速公路以北湖区（A区）,沿岸高于湖心区的分布趋势;季节变化整体表现为：夏季 > 秋季 > 春季 > 冬季,且夏季显著高于其他季节.（3）滆湖水体中无机悬浮物（ISS）和有机悬浮物所占TSS的比例差异悬殊,分别为75.5%和24.5%,A区和B区均以ISS为主.（4）线性拟合表明,TSS与颗粒态氮、总磷和颗粒态磷具有极显著正相关关系;（5） TSS与叶绿素a浓度相关性极显著.综合结果分析,藻类暴发和泥沙再悬浮是影响滆湖水体悬浮物浓度的重要因素.     

蓝藻对太湖底泥反硝化过程的影响和机理分析

通过模拟实验,研究了因自然或人工沉降的太湖蓝藻在厌氧条件下作为碳源对底泥微生物反硝化脱氮的促进作用.通过对底泥总氮、化合态氮素、挥发性脂肪酸(VFAs)、COD、电位和pH等指标的监测,发现藻体中大量的生物可降解碳素在厌氧消解后产生挥发性脂肪酸等一些可供反硝化菌直接利用的小分子物质,2×藻组VFAs含量可达2232.96μl/L,1×藻组可达1263.36μl/L,最高可达42.1%,为对照组(无添加蓝藻)的2.43倍,从而促进了硝态氮和亚硝态氮还原成N2和N₂O的过程,提高氮素的去除率.但底泥中沉降蓝藻需要一定的降解时间,前4天添加冷冻干蓝藻粉的处理组COD降解率较低,电位处于正值,体系中产生硝态氮,随后COD持续降低,添加2×藻组COD最大去除率为42.08%,1×藻组为32.93%,对照组仅为14.46%,表明藻细胞中的碳素已开始被利用.本研究表明沉降蓝藻细胞能够为底泥中的反硝化过程提供可利用碳源,并深入揭示了沉降蓝藻作为碳源促进底泥反硝化过程的机理和对底泥中C、N的影响,为在湖泊治理中降低氮素的内源污染提供了新的科学依据.     

中国长足摇蚊(Tanypus chinensis)幼虫底栖扰动对沉积物溶解氧特征及反硝化的影响

以中国长足摇蚊(Tanypus chinensis)幼虫对沉积物的生物扰动过程为研究对象,运用稳定同位素示踪及同位素配对技术,深入探讨长足摇蚊幼虫扰动对太湖梅梁湾沉积物硝酸盐界面迁移、溶解氧侵蚀深度及沉积物反硝化速率及两种不同反硝化过程(非耦合反硝化(DW)和耦合反硝化(DN))的影响.摇蚊幼虫扰动后,添加15N两种处理沉积物氧气消耗速率由355.49±131.49μmol/(m2.h)变化为546.39±261.41μmol/(m2.h),而未添加15N两种处理由313.57±61.63μmol/(m2.h)变化为554.17±184.36μmol/(m2.h),硝酸盐界面迁移结果表明:扰动显著加强了水体硝酸盐向沉积物迁移的速率,加强沉积物作为上覆水中NO3-N汇的作用,摇蚊幼虫扰动组的硝酸盐迁移速率从-33.75±29.25μmol/(m2.h)提高到-210.14±117.25μmol/(m2.h).同位素添加实验发现,摇蚊幼虫底栖扰动能显著提高沉积物总反硝化速率,与对照组相比,总反硝化速率从31.83±8.79μmol/(m2.h)上升到228.98±54.09μmol/(m2.h),增加了约6倍左右.利用同位素配对法计算对两种不同反硝化过程进行区分,发现非耦合反硝化速率从15.78±8.51μmol/(m2.h)上升到182.96±45.22μmol/(m2.h),耦合反硝化速率从16.04±5.63μmol/(m2.h)增加到46.01±8.97μmol/(m2.h),预示着底栖生物扰动能同时增加耦合和非耦合两种反硝化过程,而非耦合反硝化过程的增加强度远大于耦合反硝化.     

太湖梅梁湾水土界面反硝化和厌氧氨氧化

运用无扰动芯样实验室内流动培养、稳定同位素示踪、同位紊气态产物测定及同位素配对技术,对太湖梅梁湾北部到南部的4个梯度样点的水土界面反硝化和厌氧氨氧化速率进行研究.结果表明,梅梁湾内及湾外开敞湖区4个样点的水土界面反硝化脱氮速率为(46.36±13.26)-(16.34±22,74)μmol/(m~2·h),厌氧氨氧化脱氮速率为(7.50±2.21)-(2.05±2.90)～mol/(m~2.b).梅梁湾北部河口区水土界面总脱氮能力明显高于梅梁湾南部及开敞湖区.通过对脱氮过程的进一步研究发现.北部脱氮过程主要以上覆水硝酸盐为底物的非耦合反硝化过程(D_w)为优势过程,而梅梁湾外开敞湖区则以沉积物硝化过程耦合控制的反硝化(D_n)为主.影响D_n、D_w在反硝化中比重的主要因素是沉积物溶氧侵蚀深度和上覆水NO_3~-.浓度的差异;梅梁湾厌氧氨氧化脱氮比例占总脱氮比例为12%-14%,湾外开敞湖区则占11%,影响其比例差异的主要因子是反硝化强度的大小及其反硝化中间产物--亚硝酸盐含量的差异.     

休伦湖Saginaw湾沉积物反硝化率的测定及其时空特征

用N2生成法测定了北美休伦湖Saginaw湾1995年夏季7、8月份沉积物反硝化率,Saginaw湾内湾的沉积物反硝化率为16．0－39．6μmolN2／（m2·h）,外湾沉积反硝化率为22．7　－26．1μmolN2／（m2·h）,比较了不同湖泊沉积物反硝化率数值大小,指出休伦湖Saginaw湾水体现阶段的营养状况为贫－中营养水平．内外湾沉积物反硝化率数值波动大小与Saginaw河及休伦湖的影响有关;N2：TIN通量比值有不随采样时间的变化而变更等特性．在反硝化率测定过程中,反硝化率与O2消耗率之间有明显的正相关关系;沉积物上覆水中NH+4与NO-3之间通量值在变化趋势上有明显的负相关关系。     

太湖流域上游东苕溪干流沉积物和悬浮物的氮形态分布及影响因素

氮是影响和控制水体富营养化的重要因素,不同形态的氮对水体富营养化贡献不同.使用连续提取法对东苕溪干流悬浮物、表层沉积物样品中各形态氮含量进行测定,探讨各形态氮的分布特征及其影响因素.结果表明,东苕溪水体氮污染严重,总氮浓度均值为4.48 mg/L.悬浮物中各形态氮含量均高于沉积物,其中悬浮物中铁锰氧化态氮(IMOF-N)含量所占比例最大,均值为1506.94 mg/kg;沉积物中有机硫化物结合态氮(OSF-N)含量最高,均值为625.31 mg/kg.IMOFN、OSF-N含量受阳离子交换量、粒径影响显著,均与总氮浓度显著相关.相关性分析表明水体的性质对IMOF-N及OSF-N含量影响较显著,并且总体上对悬浮物的影响强于沉积物.另外,悬浮物有助于水体中的氮发生硝化反应向硝态氮转化,沉积物则有助于水体的氮发生还原作用向氨氮转化.在一定程度上,水体中的悬浮物对藻类具有抑制作用.     

Effects of suspended particles on the growth of two dominant phytoplankton species of Bohai Bay,China

Suspended particles (SP) are increasing dramatically in Bohai Bay, China and may affect the growth and composition of phytoplankton assembly. To determine the effects of SP on the growth of two dominant phytoplankton species, Phaeodactylum tricornutum Bohlin and Gymnodinium sp., we cultured and tested their growth characteristics under SP concentrations ranging from 0 g L⁻¹ to 0.8 g L⁻¹. Our results show that the increase in the SP concentrations results in significant decrease in the maximum cell densities and the maximum specific growth rates of these two species. The half maximal inhibitory concentration (IC₅₀) of SP to P. tricornutum and Gymnodinium sp. were 1.07 g L⁻¹ and 0.68 g L⁻¹ respectively, indicating the inhibitory effect of SP on Gymnodinium sp. was greater than on P. tricornutum. These results suggest that SP inhibits the growth of the two algal species and P. tricornutum is more tolerant to SP than Gymnodinium sp.     

洱海悬浮颗粒物和表层沉积物有机碳氮同位素来源特征及水质指示意义

为探究湖泊水体悬浮颗粒物和沉积物有机碳、氮来源及水质指示意义,分析了2013-2014年洱海悬浮颗粒物和表层沉积物有机碳同位素(δ13C)、氮同位素(δ15N)和C/N比值时空变化特征及与水质的关系.结果 表明:①洱海悬浮颗粒物δ13C、C/N、δ15N在旱、雨季差异显著(P＜0.05),旱季变化范围分别为-31.75...     

Fractionation and concentration of suspended particulate matter in natural waters

A scheme for the fractionation and concentration of suspended particulate matter (SPM) from natural waters has been tested. This scheme involves the sequential use of three fractionation techniques—sieving, continuous flow centrifugation and tangential flow filtration to collect gram amounts of SPM over the entire particulate and colloidal size range. The separation scheme is able to process large samples (ca. 1001), within reasonable times (ca. 1 day) and the apparatus is portable. Reproducibility and potential artifacts introducing during the fractionation and concentration of SPM, particularly when tangential flow filtration is used, are discussed. It has been shown that there is a systematic increase in the content of organic carbon, Mg, Ca, Na, K, Cu and Zn with decreasing particle size, highlighting the importance of the colloidal ( < 1 μm) fraction.     

Size effects of suspended particles on gill damage in green-lipped mussel Perna viridis

The green-lipped mussels Perna viridis were exposed to <500 μm suspended solids (SS) with concentrations of 0 (control), 250, 500, 750 and 1000 mg/L for 14 days, followed by transferring to clean, filtered seawater for 28 days. Results of scanning microscopy showed significantly higher damages to the cilia on the frontal surface of the gill filaments than that on the abfrontal surface in both demibranchs. Percent ciliary depletion varied with SS concentrations and time. No sign of recovery of the gill filaments was observed after the mussels were transferred to clean seawater. In a second experiment, mussels were exposed to SS with size range from <63, >125–<250 and >250–<500 μm at 600 mg/L, together with a control (0 mg/L) for 14 days, followed by transferring to clean, filtered seawater for 28 days. Results of scanning microscopy showed significant ciliary damages in both the ascending and descending lamellae under the three particle size groups as compared with the control. Percent depletion of frontal cilia was most serious for the >250–<500 μm size group and least for the <63 μm size group. However, percent depletion of abfrontal cilia was most serious for the >125–<250 μm size group and least for the <63 μm size group. No recovery of ciliary damages was observed. The effects of particle size of suspended sediments on the morphological damages of gill filaments in the green-lipped mussels were discussed.     

A simple and inexpensive turbidity meter for the estimation of suspended sediment concentrations

The relatively high cost of commercially available turbidity meters has inhibited detailed and intensive research on spatiotemporal patterns of suspended sediment transport. We describe here the electronic and physical design of an inexpensive turbidity sensor which is easy to construct, simple to interface with portable millivolt meters, dataloggers, computers, or chart recorders, consumes exceptionally small currents, and is robust and reliable. the very low individual cost allows a large number of sensors to be distributed throughout the water body of interest to facilitate turbidity mapping. Turbidity profilers to detect vertical or lateral turbidity changes in rivers, lakes, estuaries, or near-shore zones are also shown to be feasible. Test data are presented from a highly turbid glacial river in southern Iceland.     

Size effects of suspended particles on gill damage in green-lipped mussel Perna viridis

The green-lipped mussels Perna viridis were exposed to <500 μm suspended solids (SS) with concentrations of 0 (control), 250, 500, 750 and 1000 mg/L for 14 days, followed by transferring to clean, filtered seawater for 28 days. Results of scanning microscopy showed significantly higher damages to the cilia on the frontal surface of the gill filaments than that on the abfrontal surface in both demibranchs. Percent ciliary depletion varied with SS concentrations and time. No sign of recovery of the gill filaments was observed after the mussels were transferred to clean seawater. In a second experiment, mussels were exposed to SS with size range from <63, >125–<250 and >250–<500 μm at 600 mg/L, together with a control (0 mg/L) for 14 days, followed by transferring to clean, filtered seawater for 28 days. Results of scanning microscopy showed significant ciliary damages in both the ascending and descending lamellae under the three particle size groups as compared with the control. Percent depletion of frontal cilia was most serious for the >250–<500 μm size group and least for the <63 μm size group. However, percent depletion of abfrontal cilia was most serious for the >125–<250 μm size group and least for the <63 μm size group. No recovery of ciliary damages was observed. The effects of particle size of suspended sediments on the morphological damages of gill filaments in the green-lipped mussels were discussed.     

Composite suspended sediment particles in river systems: their incidence,dynamics and physical characteristics

Most of the existing data on the effective particle size characteristics of fluvial suspended sediment derive from instantaneous sampling methods that may not be representative of the overall suspended sediment loads. This presents difficulties when there is a need to incorporate effective particle size data into numerical models of floodplain sedimentation and sediment‐associated contaminant transfer. We have used a field‐based water elutriation apparatus (WEA) to assemble a large (36 flood) database on the time‐integrated nature of the effective and absolute particle size characteristics of suspended sediment in four subcatchments of the River Exe basin of southwest England. These catchments encompass a wide range of terrains and fluvial environments that are broadly representative of much of the UK and temperate, low relief northwest Europe. The WEA provides important data on the physical characteristics of composite particles that are not attainable using other methods. This dataset has allowed, for the first time, detailed interbasin comparisons of the time‐integrated particle size characteristics of suspended sediment and reliable estimates of the contribution of five effective size classes to the mean annual suspended sediment load of the study catchments. The suspended sediment load of each river is dominated by composite rather than primary particles, with, for example, almost 60% (by mass) of the sediment load of the River Exe at Thorverton transported as composite particles > 16 µm in size. All the effective size classes contain significant clay components. A key outcome of this study is the recognition that each catchment has a distinctive time‐integrated effective particle size signature. In addition, the time‐integrated effective particle size characteristics of the suspended loads in each of the catchments display much greater spatial variability than the equivalent absolute particle size distributions. This indicates that the processes producing composite particles vary significantly between these catchments, and this has important implications for our understanding of the dynamics of suspended sediment properties. Copyright © 2007 John Wiley & Sons, Ltd.     

藻源性湖泛水体显黑颗粒的元素形态分析与鉴定

湖泛现象是我国超富营养化浅水湖泊面临的最严峻环境问题之一,水体发黑、发臭是湖泛水体最显著和基本的物理特征.针对太湖湖泛显黑颗粒缺乏从元素形态直接给出证据的问题,针对室内模拟藻体和沉积物存在下形成的湖泛水体,采用多种图谱分析技术,对厌氧截留分离的显黑颗粒物质及其化学组成和元素形态进行了分析鉴定.扫描电镜-X射线能谱分析与荧光光谱分析表明:湖泛水体显黑颗粒物质以藻类残体和悬浮沉积物颗粒物为主,其组成元素以C、O、Si为主;与未发生湖泛的对照样相比,湖泛水体显黑颗粒物样品中具有更高的Fe、S含量.X射线光电子能谱Fe、S微区分析进一步表明:湖泛显黑颗粒物样品中Fe主要以Fe(Ⅱ)的形式存在、S则以还原态S2-的形式赋存,两者具有共同化合成Fe S的充要条件.因此,缺氧厌氧条件下,湖泛水体的显黑物质组成是Fe S,它可由水体中Fe2+和ΣS2-通过化学共沉淀形成,并主要通过吸附于悬浮颗粒物之上而使得整个水柱呈现黑色,指示湖泛的暴发过程和维持状态.     

A review of the influencing factors on teleseismic traveltime tomography

Teleseismic traveltime tomography is an important tool for investigating the crust and mantle structure of the Earth. The imaging quality of teleseismic traveltime tomography is affected by many factors, such as mantle heterogeneities, source uncertainties and random noise. Many previous studies have investigated these factors separately. An integral study of these factors is absent. To provide some guidelines for teleseismic traveltime tomography, we discussed four main influencing factors:the ...