东太平洋红藻诊断色素浓度的卫星遥感研究

红藻是东太平洋优势藻种之一,获取其生物量信息有助于认识浮游植物在海洋生物化学循环及物质能量交换过程中的作用。红藻中蕴含的诊断色素是准确获取其生物量信息的关键,因此,开展红藻诊断色素的反演研究具有重要科学价值。本文基于6个东太平洋航次数据集,利用三种红藻诊断色素（叶绿素c1+c2、叶绿素c3、19’-乙酰基氧化岩藻黄素）与总叶绿素a之间的“共变效应”,构建红藻诊断色素反演模型。模型验证结果表明,决定系数R2为0.68～0.88（p<0.001）,平均绝对百分比误差为39%～46%,中值误差均小于30%。卫星反演结果表明,东太平洋红藻诊断色素浓度呈现近岸高、大洋低的分布特点,且有明显的季节变化特征。本文构建的红藻诊断色素反演模型可为表征红藻分布及监测藻华灾害等研究提供数据基础与方法支撑。     

改性玉米秸秆对水中磷酸根的吸附动力学研究

将化学改性后的玉米秸秆制备阴离子交换剂,重点研究了改性玉米秸秆对磷酸根的吸附动力学特性.通过静态实验,考察了在不同pH、温度、磷酸根初始浓度条件下,改性玉米秸秆对磷酸根吸附效果的影响,并分别用伪一级动力学方程、伪二级动力学方程、修正伪一级动力学方程和颗粒内扩散方程进行拟合,计算出相应的速率常数.结果表明,Langmuir等温模式能更好地描述改性玉米秸秆对磷酸根的吸附效果,并且随着温度的升高,改性玉米秸秆对磷酸根的最大吸附量逐渐减小.改性玉米秸秆对磷酸根的吸附是一个快速吸附过程,30 min内即可达到吸附平衡,该吸附过程符合伪二级动力学方程和颗粒内扩散方程,吸附速率主要受颗粒内扩散控制.随着初始浓度的增大,伪二级吸附速率常数逐渐减小,颗粒内扩散速率常数逐渐增大.通过改性玉米秸秆对磷酸根的吸附动力学研究,可以为反应器的设计和污水处理装置的运行提供基础信息,对于去除水溶液中磷酸根的技术应用具有重要实际意义.     

Three-dimensional unstructured-mesh eutrophication model and its application to the Xiangxi River, China

The Xiangxi River is one of the main tributaries in the Three Gorges reservoir, with the shortest distance to the Three Gorges Project Dam. Severe and frequent algal bloom events have occurred frequently in the Xiangxi River in recent years. Therefore, the current study develops a three-dimensional unstructured-mesh model to investigate the dynamic process of algal bloom. The developed model comprises three modules, namely, hydrodynamics, nutrient cycles, and phytoplankton ecological dynamics. A number of factors, including hydrodynamic condition, nutrient concentration, temperature, and light illumination, that would affect the evolution of phytoplankton were considered. Moreover, the wave equation was used to solve the free surface fluctuations and vertical Z-coordinates with adjustable layered thicknesses. These values, in turn, are suitable for solving the algal bloom problems that occurred in the river style reservoir that has a complex boundary and dramatically changing hydrodynamic conditions. The comparisons between the modeling results and field data of years 2007 and 2008 indicate that the developed model is capable of simulating the algal bloom process in the Xiangxi River with reasonable accuracy. However, hydrodynamic force and external pollution loads affect the concentrations of nutrients, which, along with the underwater light intensity, could consequently affect phytoplankton evolution. Thus, flow velocity cannot be ignored in the analysis of river algal bloom. Based on the modeling results, building an impounding reservoir and increasing the releasing discharge at appropriate times are effective ways for controlling algal bloom.     

Removal of phosphate ions from aqueous solution using Tunisian clays minerals and synthetic zeolite

Phosphate ions are usually considered to be responsible for the algal bloom in receiving water bodies and aesthetic problems in water. From the environmental point of view, the management of such contaminant and valuable resource is very important. The present work deals with the removal of phosphate ions from aqueous solutions using kaolinitic and smectic clay minerals and synthetic zeolite as adsorbent. The pH effect and adsorption kinetic were studied. It was found that phosphate could be efficiently removed at acidic pH (between 4 and 6) and the second order model of kinetics is more adopted for all samples. The isotherms of adsorption of phosphate ions by the two clays and the zeolite samples show that the zeolite has the highest rate of uptake (52.9 mg P/g). Equilibrium data were well fitted with Langmuir and Freundlich isotherm.     

基于宏条形码技术的白洋淀水华藻类识别及其驱动因子分析

浮游藻类是引起水华暴发的主要原因.为筛选潜在水华藻类,评估白洋淀水华风险区域,于2020年8月对白洋淀373点位展开浮游藻类调查.利用宏条形码技术分析,解析水华藻类群落组成,同时采用显微镜计数法统计藻密度.根据总藻密度对白洋淀不同区域的水华程度进行评估,同时进一步针对水华藻类群落,耦合淀区水质条件,探究白洋淀不同区域水华藻类群落空间差异驱动因子,以甄别影响水华藻类群落结构关键环境因子.结果表明,95%以上采样区域无水华风险(藻类密度<2×10⁶个·L^-1),仅5个样点存在轻微水华风险.但水华藻类群落分析共检测到了90种水华藻类,其中优势水华藻种有20种,隶属于以绿藻门、蓝藻门和裸藻门为主.水华藻类群落结构在不同区域上具有显著空间异质性(P<0.05).关键驱动因子解析结果表明,总磷(TP)、总氮(TN)和氨氮(NH⁺₄-N)是造成水华藻类群落结构差异的关键因子.其中,门水平上,蓝藻门水华藻类与以上关键因子显著正相关;种水平上,硅藻门和绿藻门水华藻类与关键因子响应更显著.因此,水华藻类群落...     

Bioaccumulation of toxic hydrophobic organic compounds at the primary trophic level

The prevailing hypothesis, which states that the uptake of HOCs by phytoplankton is controlled by the compound's lipophilicity (Kow) was tested. The approach taken was to determine the factors that controlled the uptake of PCBs by phytoplankton under controlled laboratory conditions, and to develop a model that would describe bioaccumulation of PCBs in phytoplankton.The results demonstrate a relationship of BAF to Kow and to phytoplankton surface properties, as well as the data presented here, support the hypothesis that the mechanism of HOC uptake is a rapid surface sorption followed by a slower transfer into lipids in the cell matrix. The work on the kinetics of uptake indicates that equilibrium is reached slowly and that the rate of uptake is of similar magnitude as phytoplankton growth under normal field conditions.Thus a critical factor that controls the bioaccumulation of HOCs reach equilibrium in phytoplankton itself.     

太湖蓝藻水华衰亡对沉积物氮、磷释放的影响

在太湖草型区、藻型区及河口区采集原状泥柱进行加藻培养实验,监测培养过程中溶解氧(DO)、总氮(TN)、总磷(TP)、氨氮(NH4+-N)、磷酸根(PO43--P)等相关指标的变化.结果表明,蔽光培养导致加藻体系中蓝藻大量死亡,形成水体极度缺氧环境(DO接近0),沉积物氮、磷释放量改变,上覆水NH4+-N、PO43--P...     

滇池沉积物中磷的释放行为研究

滇池分为草海和外海两个水体,且草海污染较外海严重,但是外海的藻类爆发的频率和强度都高于草海。通过实验室模拟,研究了滇池草海与外海沉积物中磷的释放行为及其藻类爆发程度不同的原因。结果表明,两个沉积物中磷的释放动力学都表现了非单一的扩散过程,拟二级动力学模型可以较好描述释放过程。草海比外海总磷高7倍,但是在水中的释放只高2倍。对两个沉积物而言,由于与表面附着的磷有竞争作用,溶解胡敏酸的加入都显著增大了磷的释放。与草海相比,外海的水交换速率慢、水深浅、沉积物有机质含量低、内源磷释放强以及对外源磷缓冲能力弱,这些特征都是有利于藻类爆发的条件。研究表明抑制滇池藻类爆发要同时考虑对外源磷和内源磷的控制。     

^15N isotope fractionation in an aquatic food chain： Bellamya aeruginosa （Reeve） as an algal control agent

15N isotope tracer techniques and ecological modeling were adopted to investigate the fractionation of nitrogen,its uptake and transformation in algae and snail(Bellamya aeruginosa Reeve).Different algal species were found to differ in their uptake of nitrogen isotopes.Microcystis aeruginisa Ktz.demonstrated the greatest 15N accumulation capacity,with the natural variation in isotopic ratio(δ 15N) and the isotope fractionation factor(ε,‰) being the highest among the species investigated.The transformation and utilization of 15N by snails differed depending on the specific algae consumed(highest for Chlorella pyrenoidosa Chick.,lowest for M.aeruginisa).When snails was seeded in the experimental pond,the algae population structure changed significantly,and total algal biomass as well as the concentration of all nitrogen species decreased,causing an increase in water transparency.A model,incorporating several chemical and biological parameters,was developed to predict algal biomass in an aquatic system when snails was present.The data collected during this investigation indicated that the gastropods such as snails could significantly impact biological community and water quality of small water bodies,suggesting a role for biological control of noxious algal blooms associated with eutrophication.     

多层营养盐协同作用的藻类生长模型研究

不同形态的营养盐在不同介质(层面)中会对藻类生长产生不同的影响,本研究构建了同时考虑水环境中、藻细胞膜界面上和藻细胞膜内营养盐浓度,尤其营养盐在藻细胞界面吸附/脱附作用的藻类生长数值模型,通过数值计算进行了参数率定和验证.结果显示,实验测试值与本模型计算值的平均相对误差小于6.90%,而且,本模型与未考虑营养盐吸附/脱附作用模型的最大绝对值累积相对误差分别为11.70%和34.18%.显然,本研究提出的这种藻类生长模型与实测数据吻合更好,能够更准确、合理和真实地描述藻类生长状态与变化趋势.本模型反映出的细胞膜界面浓度,体现了藻细胞在光暗交替情况下吸收营养盐的变化,同时表达了藻细胞内部ATP浓度的变化状态,使外界营养盐浓度同藻细胞自身营养状态之间,也就是在微观和中观层次之间建立起具有理论指导意义的相互关联作用.     

三峡库区流域藻类生长与营养盐吸收关系

根据三峡库区流域的实测数据和描述富营养污染流域中水华暴发强非线性耦合动力学模型中的控制函数,研究了缓流态水体环境中藻类生长的内在机制,并以长江三峡流域优势藻类,即绿藻的生长为例,较为系统地研究了藻类生长对N、P的吸收与水体中N、P浓度之间存在的强相互作用;藻类对营养物的吸收率ω_i与水体中营养物浓度c_x的比值(ω_i/c_x)不仅反映出三峡水域中藻类浓度对藻类吸收营养物程度的影响,而且在藻类生长与吸收各种营养成分之间还存在明显的关联性.     

三峡水库大宁河回水区藻类生长与三态磷盐变化特征分析

多年的调查数据表明,每年的3～6月是大宁河回水区水体营养盐及藻类含量增长期。在2011年3—6月对大宁河回水区整个区域的调查过程中发现,水体磷盐含量从回水区上游至入长江河口逐渐增大,总磷0．010～0．257mg／L,溶解性磷0．010～0．208mg／L,正磷酸盐0．010～0．179mg／L;磷盐3个指标中,正磷酸盐变异性最大（各断面59％～85％）,能够较好地反映藻类消耗磷盐的情况。正磷酸盐和藻类生物量呈显著负相关关系,且在自然水体中有明显分层。在室内培养条件下采用线性关系粗略分析,藻类能在水体正磷酸盐含量较低时释放和转化磷盐,其藻类生物量理论极限容量值略高于天然状态。室内培养藻类发现,藻类生长过程中先是个体的增长,之后数量增殖,但平均体积会变小。藻类生长活性有一个由强到弱然后再增强的过程,而较低正磷酸盐浓度会抑制藻类的生物活性使其一直处于一个较低的水平。     

藻类在大连湾的水环境行为数值模拟研究

应用三维水质模型对大连湾水体中的藻类碳浓度的时空变化规律以及其影响因素进行了研究,选择主要的模型参数进行了灵敏度分析。由空间分布的模拟结果可知,在大连湾,藻类主要集中在排污口附近区域。由季节变化模拟结果可知,在湾顶部的排污口区藻类生产显示明显的季节变化趋势,在夏季,主要受到磷酸盐浓度的限制。灵敏度分析显示,在排污口区水体的扩散能力对藻类生产的影响较大,在湾中部和湾口区主要受到磷酸盐负荷的影响。模拟结果可以为大连湾的污染控制、水质规划和管理提供科学依据。     

Removal of Crystal Violet from aqueous solution using powdered mycelial biomass of Ceriporia lacerata P2

A simple and efficient biosorbent prepared from powdered mycelial biomass of Ceriporia lacerata was used to removal Crystal Violet, poorly degraded as recalcitrant molecule by microorganism.     

淀山湖浮游藻类群落的早期增长

对2004～2009年淀山湖浮游藻类群落生物量[以叶绿素a（Chla）表示]随时间的变化进行了数学模拟.模拟结果表明,Logistic增长模型能够很好地描述淀山湖浮游藻类群落春季和夏季的早期增长.一般说来,淀山湖春季以硅藻和绿藻为主的浮游藻类群落于2月下旬进入指数级增长,到3月上旬浮游藻类密度已经达到始盛点的2倍,浮游...     

PAFC-PDM复合混凝剂强化混凝去除水库源水中的藻类

将聚二甲基二烯丙基氯化铵(PDMDAAC)与聚合氯化铝铁(PAFC)复合制备了新型复合混凝剂PAFC–PDMDAAC (PAFC-PDM),对含藻的水库原水进行强化混凝处理研究.研究对比了PAFC-PDM,PAFC与预氯化工艺的除藻效果,并对其混凝除藻机理进行了初步探讨.结果表明,对于藻细胞数为7.98×106~1.17×107cells/L和浊度为2.56~3.59NTU的水库原水,当PAFC-PDM投加量为1.0mg/L时(以Al2O3计),藻类和浊度的去除率分别达到93.5%和81.7%,显著优于PAFC的混凝处理效果;对藻细胞进行扫描电镜和预氯化副产物分析表明,预氯化杀藻除藻方法,不仅破坏了藻细胞结构,而且产生了三卤甲烷类氯化消毒副产物,影响饮水水质;采用PAFC-PDM强化混凝工艺除藻,不破坏藻细胞,无消毒副产物.     

Photo-induced transformations of Hg(Ⅱ) species in the presence of Nitzschia hantzschiana,ferric ion,and humic acid

Effects of algae Nitzschia hantzschiana, Fe(Ⅲ) ions, humic acid, and pH on the photochemical reduction of Hg(Ⅱ) using the irradiation of metal halide lamps (λ 365 nm, 250 W) were investigated. The photoreduction rate of Hg(Ⅱ) was found to increase with increasing concentrations of algae, Fe(Ⅲ) ions, and humic acid. Alteration of pH value affected the photoreduction of Hg(Ⅱ) in aqueous solution with or without algae. The photoreduction rate of Hg(II) decreased with increasing initial Hg(Ⅱ) concentration in aqueous solution in the presence of algae. The photochemical kinetics of initial Hg(Ⅱ) and algae concentrations on the photoreduction of Hg(Ⅱ) were studied at pH 7.0. The study on the total Hg mass balance in terms of photochemical process revealed that more than 42% of Hg(Ⅱ) from the algal suspension was reduced to volatile metallic Hg under the conditions investigated.     

贵州百花湖水库浮游植物群落结构与季节变化

为揭示水库浮游植物群落结构对放养鲢、鳙鱼控藻的响应特征,分四季对百花湖的水质及浮游植物进行了调查和分析。浮游植物种类较多,共检出浮游植物147种,绿藻在种类组成上占绝对优势,共计76种,其次为硅藻31种、蓝藻27种、隐藻、甲藻和裸藻各4种,金藻仅1种。浮游植物丰度在9.69×106～150.89×106 cells/L之间,生物量在3.57～16.80mg/L之间;蓝藻在丰度上占优势,其主要物种类群是假鱼腥藻属;硅藻则在生物量上占优势。浮游植物组成随季节变化而不同,冬季以蓝藻、硅藻和绿藻为优势类群;春季硅藻和绿藻减少而蓝藻增加;夏季以蓝藻、硅藻和隐藻为优势类群;秋季以蓝藻、硅藻、隐藻和绿藻为混合优势类群。百花湖浮游植物形成以假鱼腥藻占绝对优势的群落结构可能与放养鲢、鳙鱼有关。     

Growth characteristics of algae during early stages of phytoplankton bloom in Lake Taihu, China

Three treatments, sediment plus lake water (S+W), sterilized sediment plus lake water (SS+W), and sediment plus filtered lake water (S+FW), were recruited to investigate the growth characteristics of algae during pre-bloom and the importance of algal inocula in the water column and sediment. The results showed that in the water column, biomass of all algae increased in all treatments when recruitment was initiated, whereas this tendency differed among treatments with further increment of temperature. The process of algal growth consisted of two stages: Stage I, the onset of recruitment and Stage II, the subsequent growth of algae. Compared with S+W, in Stage I, SS+W significantly increased the biomass of cyanophytes by 178.70%, and decreased the biomass of non-cyanophytes by 43.40%; In Stage II, SS+W notably stimulated the growth of all algae, thus incurring the occurrence of phytoplankton bloom. Further analyses revealed that both metabolic activity and photochemical activity of algae were enhanced in SS+W, which resulted from the releasing of nutrients from sediment. These results suggest that algal growth in Stage II and algal inocula in the water column can be important factors for the formation of phytoplankton bloom. In addition, possible mechanisms promoting algal recruitment and subsequent growth of algae were explored.     

水华束丝藻对汞的吸附-解吸特征

通过室内模拟实验,探究不同丰度的活、死水华束丝藻对Hg²⁺的吸附动力学特征和等温吸附模型以及解吸特征。结果表明,水华束丝藻对Hg²⁺有较好的吸附效果,能在短时间内吸附大量Hg²⁺,120 min左右达到吸附平衡,且活藻对Hg²⁺的吸附效果比死藻好;活藻和死藻吸附Hg²⁺的动力学过程符合准一级、准二级动力学模型,且准二级动力学模型拟合效果更好;活、死水华束丝藻对Hg²⁺的吸附分别符合Langmuir模型、D-R模型,最大吸附量分别为2.07×10^-2 ng/（10⁶ cells）、3.56×10^-2 ng/（10⁶ cells）;水华束丝藻对Hg²⁺的单位吸附量随着藻丰度的增加而减少,吸附总量随着藻丰度的增加而增加。反应初期（0～5 min）,活、死水华束丝藻对Hg²⁺进行生物吸附,吸附速度快且效率高;随后活藻依靠新陈代谢将Hg²⁺转移至细胞内进行生物富集,因而活藻的单位吸附量高于死藻。活藻和死藻对Hg²⁺的解吸量随藻丰度的增加而增加,且死藻变化更明显。