底泥翻耕对巢湖西部聚藻区黑臭风险的预控效果

聚藻区高有机负荷表层底泥已被证实是西巢湖黑臭频发的主要因素,但能否借鉴像控制湖泊内源污染的翻耕方式对黑臭进行预控,则有待于与过程有关的试验研究.基于湖泊底泥再悬浮特征和耕作性能设计的底泥翻耕措施,借助能够模拟湖泊风浪与沉积物再悬浮的大型装置,通过藻体堆积诱发试验,研究黑臭诱发过程中上覆水水色,ρ（Fe2+）、ρ（S2-）的动态,新生沉积物-水界面底泥关键物化指标以及底泥间隙水Fe、S变化对底泥翻耕的响应过程.结果表明:①翻耕深度对黑臭影响较大,PT15（15 cm深度的翻耕处理组）达到了对湖泛黑臭的控制,当第8~14天PT2、PT5、PT10（2、5和10 cm翻耕处理组）,CK（对照组）和Blank（空白组）相继发生黑臭时,PT15上覆水主要致黑物质为Fe2+和S2-,其质量浓度分别为PT2、PT5、PT10、CK和Blank的68.6%、79.5%、48.1%、46.7%、51.3%和75.2%、65.7%、57.1%、74.5%、75.0%.②PT15可明显提升新生泥-水界面对蓝藻堆积及缺氧环境的耐受力,黑臭诱导模拟后,其底部水体及泥-水界面的ρ（DO）、E_h和pH均远高于发生湖泛黑臭处理组,ρ（∑H₂S）却明显低于发生湖泛黑臭处理组,表层底泥间隙水中ρ（Fe2+）为0.54 mg/L,仅为发生湖泛黑臭处理组的25.3%~33.7%,ρ（Fe2+）占ρ（TFe）的比例为25.2%,远低于发生湖泛黑臭处理组（约40.0%）,表层底泥中w（AVS）（AVS表示酸可挥发性硫化物）为0.51 μg/g,仅为发生湖泛黑臭处理组的14.6%~17.2%.研究显示,底泥翻耕作为一种底泥物理改良方式,对于聚藻区内底泥,因其将有机污染负荷较重的表层翻转至了下层,阻隔了表层污染底泥中物质迁移供给和对厌氧微生物参与的控制,在藻体大量聚集和死亡的水柱环境中可较好地阻止致黑致臭物的形成,有效控制了湖泛黑臭的发生.      

Associations between Water Physicochemistry and Prymnesium parvum Presence,Abundance, and Toxicity in West Texas Reservoirs

Toxic blooms of golden alga (Prymnesium parvum) have caused substantial ecological and economic harm in freshwater and marine systems throughout the world. In North America, toxic blooms have impacted freshwater systems including large reservoirs. Management of water chemistry is one proposed option for golden alga control in these systems. The main objective of this study was to assess physicochemical characteristics of water that influence golden alga presence, abundance, and toxicity in the Upper Colorado River basin (UCR) in Texas. The UCR contains reservoirs that have experienced repeated blooms and other reservoirs where golden alga is present but has not been toxic. We quantified golden alga abundance (hemocytometer counts), ichthyotoxicity (bioassay), and water chemistry (surface grab samples) at three impacted reservoirs on the Colorado River; two reference reservoirs on the Concho River; and three sites at the confluence of these rivers. Sampling occurred monthly from January 2010 to July 2011. Impacted sites were characterized by higher specific conductance, calcium and magnesium hardness, and fluoride than reference and confluence sites. At impacted sites, golden alga abundance and toxicity were positively associated with salinity‐related variables and blooms peaked at ~10°C and generally did not occur above 20°C. Overall, these findings suggest management of land and water use to reduce hardness or salinity could produce unfavorable conditions for golden alga.     

Influence of zeta potential on the flocculation of cyanobacteria cells using chitosan modified soil

Using chitosan modified soil to flocculate and sediment algal cells has been considered as a promising strategy to combat cyanobacteria blooms in natural waters. However, the flocculation efficiency often varies with algal cells with different zeta potential (ZP) attributed to different growth phases or water conditions. This article investigated the relationship between ZP of Microcystis aeruginosa and its influence to the flocculation efficiency using chitosan modified soil. Results suggested that the optimal removal efficiency was obtained when the ZP was between -20.7 and -6.7 mV with a removal efficiency of more than 80% in 30 min and large floc size of >350 μm. When the algal cells were more negatively charged than -20.7 mV, the effect of chitosan modified soil was depressed (<60%) due to the insufficient charge density of chitosan to neutralize and destabilize the algal suspension. When the algal cells were less negative than -6.7 mV or even positively charged, a small floc size (<120 μm) was formed, which may be difficult to sink under natural water conditions. Therefore, manipulation of ZP provided a viable tool to improve the flocculation efficiency of chitosan modified soil and an important guidance for practical engineering of cyanobacteria bloom control.     

Cyanobacterial bloom dynamics in Lake Taihu

<正>Lake Taihu is the third largest freshwater lake in China and serves as an important drinking water source for the local populace;however,decades of excessive nutrient loading fueled by anthropogenic activities have resulted in hypertrophic conditions,promoting the annual formation of nuisance phytoplankton blooms(Chen et al.,2003;Duan et al.,2009)     

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...     

铁改进型蓝藻生物炭的制备及对地表水中磷的协同吸附机制

为缓解水体富营养化以及蓝藻堆积问题,采用经过聚合硫酸铁(PFS)脱水后的蓝藻制备生物炭吸附水体中的磷酸盐,其中生物炭经过水蒸气活化调节孔隙结构.通过响应面法对蓝藻生物炭的制备条件进行优化.当PFS投加量为458 mg·L^-1、碳化温度为433℃和生物炭前体物与水蒸气的质量比为1∶11.选取不加PFS生物炭(F₀H₁₁-433)与加PFS生物炭(F₄₅₈H₁₁-43)进行X射线衍射(XRD)、傅里叶红外光谱(FTIR)、 Zeta电位和拉曼光谱(Raman)表征,来研究蓝藻生物炭与PFS对磷酸盐的去除是否具有协同效应.结果表明,与F₀H₁₁-433相比,F₄₅₈H₁₁-433表面出现铁氧化物,零电荷点(pH_pzc)从4.41提高到6.19,生物炭的无序、缺陷程度得到提高.准二级动力学模型和Langmuir模型适用于描述F₄₅₈H₁₁     

太湖金墅港区域冬春季硅藻群落变化及其影响因素分析

采用Illumina高通量测序技术研究太湖金墅港区域的硅藻群落结构及其与环境因子之间的相关性。2019年11月—2020年4月共检测到28个属的硅藻种类,主要包括小环藻属（Cyclotella sp.）、菱形藻属（Nitzschia sp.）、直链藻属（Aulacoseira sp.）、波缘藻属（Cymatopleura sp.）、辐环藻属（Actinocyclus sp.）和骨条藻属（Skeletonema sp.）等,还出现了海洋生境种类海链藻属（Thalassiosira sp.）。结果表明,12月和3月硅藻为金墅港水域的优势种,水温与硅藻群落数量的相关性最强。     

二氧化氯预氧化对藻类絮体形态的影响

针对高含藻高含盐杨埕水库原水藻类特征,采用聚合氯化铝(PAC)、硫酸铝(AS)、聚合硫酸铁(PFS)和氯化铁(FC)4种混凝剂进行混凝除藻试验,用图像法对藻类絮体的分形维数进行测定,分析混凝剂种类及投量、二氧化氯投加量等因素对混凝除藻效果及藻类絮体形态的影响。结果表明,杨埕水库夏季藻类种属相对较为单一,以小型色球藻、微小平裂藻、不整齐蓝纤维藻为优势藻类;4种混凝剂的除藻性能优劣依次为:AS>PAC>PFS>AC。在AS最佳投加量(以Al2SO4计)70 mg/L下,藻类的去除率为85.3%。此时,杨埕水库夏季藻类以藻类絮体分形维数值为1.54,形成的絮体密实且沉降性好。以AS为混凝剂,投加量为70 mg/L下,二氧化氯投加量为0.8 mg/L时助凝效果最好,藻类的去除率比单独投加AS时提高了6.3%,藻类絮体分形维数值为1.71,形成的藻类絮体更加密实。二氧化氯过量投加无益于藻类去除。     

藻类对偶氮染料的降解及定量结构-生物降解性研究

通过研究普通小球藻（ Chlorella vulgaris） 、蛋白核小球藻（Chlorella pyrenoidosa） 、斜生栅藻（Scenedes nusobliquus） 对偶氮染料的降解作用,筛选出优势藻种并优化降解条件;对单偶氮染料进行了定量结构—生物降解性相关关系（QSBR） 研究．3 种藻均能利用偶氮染料为其生长的唯一 C、 N 源,使染料脱色,蛋白核小球藻具有更强的脱色能力;且藻在无 N 环境中的脱色率明显高于无 C 和正常环境;pH 值对染料脱色影响较大,最佳pH值为中性;不同结构的单偶氮染料生物降解性相差很大,脱色率为9.1 ％ （89.9 ％ , QSBR 研究表明, 偶氮键的最低未占据轨道能量是控制生物降解的主要因素,而脱色率与染料的分子量无关．     

三价砷对藻类群落结构的影响

为了探讨三价砷对微型生物群落结构的影响,进而评价水质,采用Ｃａｉｒｎｓ提出的ＰＦＵ方法在群落级水下上模拟研究了Ａｓ＾３＋对藻类群落的毒性,结果表明,藻类类群随着Ａｓ＾３＋浓度增大而减少,多样性指数随Ａｓ＾３＋浓度增加而明显下降,藻类群落迁入速率随时间延长而下降,消失速度则随时间而上升,Ａｓ＾３＋对藻类群落结构在ＬＯＥＣ为３２ｍｇ／Ｌ和５６ｍｇ／ＬＮＯＥＣ为１ｍｇ／Ｌ,结果表明用藻类群落在ＰＦＵ上群