蓝藻资源化技术研究及应用进展

针对蓝藻资源化问题,概述国内外利用蓝藻制备有机肥、提取高纯度藻蓝蛋白、制备活性炭和藻粉这4种利用方式的特点、现状及应用进展。提出,应从高温好氧堆肥技术、藻蓝蛋白提取技术和藻水分离技术这3个方面,解决其关键技术问题并进行进一步研究开发。     

基于哨兵-3A卫星OLCI数据的最大叶绿素指数在太湖蓝藻水华监测中的应用

欧洲航天局于2016年2月16日成功发射哨兵-3A卫星,搭载的水色遥感仪器(OLCI)提供了很好的海洋和内陆水体生态指标观测反演能力。基于OLCI获取的太湖L1b级遥感数据产品,利用OLCI Oa10、Oa11、Oa12波段计算了重要的水色/水生态遥感指标,即最大叶绿素指数(MCI),在此基础上初步分析了MCI在太湖蓝藻水华监测预警中应用效果。研究表明:(1)哨兵-3A卫星OLCI影像质量清晰,构建的MCI能够反映太湖水体叶绿素信号强度;(2)与常用的归一化植被指数相比,在蓝藻没有明显积聚的藻-水混悬水域,MCI与叶绿素浓度有很好的关联,可更灵敏地反映叶绿素浓度的空间分布特征。MCI将在蓝藻监测上具有更好的适用性,可有效提高富营养湖泊蓝藻水华的预警预报精度。     

压力强化混凝除藻工艺中藻毒素安全性研究

为了研究预压力强化混凝沉淀蓝藻水处理工艺中,外加压力是否会引起藻细胞破裂,导致细胞内藻毒素泄漏到水体中,影响供水安全,实验对比研究了预压力和预氧化含藻水后藻毒素浓度的变化,以及预压力混凝沉淀和预氧化混凝沉淀除藻工艺中藻毒素浓度的变化和藻类去除效果.结果表明,含藻水经0.4~0.8 MPa压力加压后,水中藻毒素浓度没有增加,而次氯酸钠预氧化后水中藻毒素浓度大幅度增加.在0.5~0.8 MPa压力范围内,加压后混凝沉淀取得了较好的除藻除浊效果,蓝藻去除率达到90%~93.5%,浊度1.23~1.95 NTU,而次氯酸钠预氧化混凝沉淀后,蓝藻去除率56.2%~78.8%,浊度8.01~10.7 NTU,说明压力强化混凝沉淀除藻工艺是安全有效的.     

巢湖藻类生物量季节性变化特征

在2008年对巢湖浮游藻类的生态分布进行了为期1 a的调查研究,并采用自制"藻类上浮/下沉捕集器"定量研究了水柱中藻类上浮和下沉速率的季节性变化.结果表明,蓝藻为巢湖主要的水华优势群落,但各个季节优势水华种群有所差别,春季鱼腥藻占优势,微囊藻次之;夏、秋两季微囊藻占绝对优势.5月开始,水柱中藻类生物量明显增加;8月份达到最大值,叶绿素含量全湖平均为146.37 mg.m-3.表层沉积物中藻类生物量在9.75～16.24 mg.kg-1之间,最小值出现在夏季,然后逐渐升高,最大值出现在冬季的11月.研究期间(5～10月),水柱中浮游藻类一直存在上浮和下沉现象,上浮速率在总体上呈先上升后下降的趋势,最大值出现在8月初,为0.036 8 mg.(m2.d)-1;下沉速率则呈现先缓慢上升后急剧下降的趋势,最大值出现在9月初,为0.032 1 mg.(m2.d)-1.多元逐步回归统计表明,温度是巢湖藻类生物量变化最为显著的影响因子,其次为总氮(TN)和总磷(TP).     

太湖饮用水源地蓝藻水华预警监测体系的构建

从预警机制的建立与分工、预警监测时间的确定、预警监测的启动、预警信息的发布、预警监测的终止、预警监测的工作流程等方面，建立了太湖引用水源地蓝藻水华预警监测体系。指出了政府必须在资金、物资、人才、技术等方面给予预警监测体系充足的保障，确保预警监测体系长期有效地运行。     

Non-microcystin producing Microcystis wesenbergii (Komárek) Komárek (Cyanobacteria) representing a main waterbloom-forming species in Chinese waters

It is well known that several morphospecies of Microcystis, such as Microcystis aeruginosa (Kützing) Lemmermann and Microcystis viridis (A. Brown) Lemmermann can produce hepatotoxic microcystins. However, previous studies gave contradictory conclusions about microcystin production of Microcystis wesenbergii (Komárek) Komárek. In the present study, ten Microcystis morphospecies were identified in waterblooms of seven Chinese waterbodies, and Microcystis wesenbergii was shown as the dominant species in these waters. More than 250 single colonies of M. wesenbergii were chosen, under morphological identification, to examine whether M. wesenbergii produce hepatotoxic microcystin by using multiplex PCR for molecular detection of a region (mcyA) of microcystin synthesis genes, and chemical analyses of microcystin content by ELISA and HPLC for 21 isolated strains of M. wesenbergii from these waters were also performed. Both molecular and chemical methods demonstrated that M. wesenbergii from Chinese waters did not produce microcystin.     

Visible light photocatalytic bismuth oxide coatings are effective at suppressing aquatic cyanobacteria and degrading free-floating genomic DNA

Access to safe drinking water free from microbial pollution is an issue of global concern. The use of photocatalytic thin films in water treatment has focused on titanium dioxide, which requires UV-activation, proving a potential barrier to upscaling and implementation in the real world. Visible-light-activated photocatalytic thin films, such as bismuth oxide, have recently been shown to have antimicrobial properties. However, more understanding of the photocatalytic effect on the microbial population in water is required. Glass beads coated with bismuth oxide were incubated with either Microcystis aeruginosa, Anabaena sp. or free-floating genomic DNA. The presence of bismuth oxide-coated glass beads was able to rapidly stop a population of cyanobacteria from increasing. The coated beads were also able to degrade genomic DNA. Leachate from the beads showed no increase in toxicity against human liver cells. This data demonstrates the efficacy of bismuth oxide-coated glass beads for controlling potentially dangerous cyanobacterial populations, whilst potentially reducing the amount of free-floating genomic DNA (an essential issue in the face of antimicrobial resistance) – all of which should be essential considerations in emerging water treatment technologies.     

鄱阳湖蓝藻分布及其影响因素分析

利用鄱阳湖的原位监测数据,分析鄱阳湖水华蓝藻的分布现状及其影响因素,探索鄱阳湖水华蓝藻的源头.研究结果表明,鄱阳湖浮游植物的优势种为硅藻,蓝藻为鄱阳湖的次级优势种,蓝藻在浮游植物总生物量的比例有逐年增加的趋势.水华蓝藻的主要优势种为鱼腥藻,其次为微囊藻和浮游蓝丝藻. 鄱阳湖蓝藻水华形成初期的基本规律为水华蓝藻在营养盐浓度相对较高且水流较缓的内湾及尾闾区生长分布,在夏秋季水位较高时在水流和风的作用下向主航道输移聚集. 结合鄱阳湖水文特点,主航道的水华蓝藻聚集有可能是上游四个湖区的蓝藻向下游漂移综合作用的结果.研究成果可为控制鄱阳蓝藻水华区域风险灾害提供基础数据.     

重金属离子胁迫对赤潮微藻的急性毒性

重金属污染和赤潮都是较为突出的海洋环境问题,为给相关研究提供基础试验数据,在实验室条件下研究了Cu2+、Cd2+、Zn2+对米氏凯伦藻和微小原甲藻的急性毒性效应. 通过2种藻的EC₅₀(半数抑制浓度)比较了其敏感性差异,分析了不同浓度重金属胁迫对微藻的影响;同时,利用TEM (transmission electronic microscopy,透射电镜技术)和FCM (flow cytometry,流式细胞术)研究了重金属Cu2+的急性毒性胁迫在亚细胞水平上对米氏凯伦藻的损伤. 其中,Cu2+、Cd2+、Zn2+对微小原甲藻的48 h EC₅₀和96 h EC₅₀分别为0.514和0.276 mg/L、0.835和1.215 mg/L及4.376和7.976 mg/L;对米氏凯伦藻的48 h EC₅₀和96 h EC₅₀分别为1.881和1.881 mg/L、5.405和6.268 mg/L及13.134 和18.732 mg/L. 结果表明:2种微藻的种群相对增长率随着胁迫浓度的增加而下降,3种重金属离子的毒性表现出Cu2+>Cd2+>Zn2+的趋势,微小原甲藻对重金属胁迫更敏感;Cu2+胁迫可使米氏凯伦藻细胞体积增大,内容物复杂程度增高,但叶绿素a的MFI(mean fluorescence intensity,平均荧光强度)的变化不明显;Cu2+胁迫对藻膜结构的损伤较明显,但对线粒体及叶绿体的结构影响不明显.