附着性藻类生长-迁移模型及其在南水北调中线工程中的应用

附着性藻类广泛存在于自然水体中,有很强的生命力且能通过释放孢子/配子等多种方式进行繁殖与迁移.传统附着藻类生长模型往往仅考虑了藻类生长过程及水动力影响,但藻类的繁殖迁移过程也是附着藻类生活史的重要部分.通过在传统附着藻类生长模型中引入繁殖迁移过程,构建了适用于附着性藻类的生长-迁移模型,并通过相关实验结果进行了率定验证...     

不同形态氮对富营养化水源藻华暴发的潜在影响

富营养水源藻华的暴发是给水厂进行水质处理的一大难题.通过设计正交试验,研究了不同营养水平下的硝酸氮、亚硝酸氮、氨氮随藻类生长的变化情况.结果表明,在设计系列中,当N:P=36时,藻类的生长数目达到最大;藻类在吸收N源时更倾向于吸收有机氮DON而不是无机氮DIN;无机氮的利用中藻类倾向于先吸收氨氮而不是硝态氮.     

水动力条件对藻华的影响

水动力条件在湖泊富营养化及藻华爆发的过程中起着决定性的作用.研究了水动力条件对藻类生长的影响,从而找出控制藻类生长的关键因素和相关参数.对于防治藻华具有重要意义.     

遮光对潘家口水库藻类生长影响的围隔实验

藻类的生长与自身通过光照进行光合作用有着密不可分的关系.利用野外围隔实验,通过对叶绿素a含量、藻细胞密度、pH、DO、TN和TP浓度变化的分析,研究了不同的遮光方式对藻类生长的影响.实验结果表明:遮光对藻类生长有明显的抑制作用,遮光围隔内的叶绿素a含量、藻细胞密度、pH和DO含量较未遮光围隔明显偏低,TN 及TP浓度较未遮光围隔明显偏高;拆除遮光材料后,藻类能迅速恢复生长,叶绿素a含量、藻细胞密度、pH和DO含量迅速升高,TN及TP浓度迅速下降.     

利用灰色关联方法分析水位缓慢下降对藻类生长的影响

在营养盐比较丰富的水体环境中,水动力条件对藻类生长的影响程度比较突出。通过对比试验,研究水位下降对藻类生长的影响。结果表明,水位下降能改变藻类的生长速度,在一定程度上促进了藻类的生长。     

景观水藻类培养试验研究

由于水流滞缓、自净能力差,景观水体极易发生藻华,对影响藻类生长的各种因素进行研究将有助于景观水体水质的控制与改善。以天津市区的津河水及开发区西区的景观河道水为试验用水,进行室内藻类生长潜力试验研究。叶绿素数据表明,西区河水的叶绿素a浓度显著高于津河水。分组统计分析显示,可溶性磷是影响这两种水体中藻类生长的关键影响因子。对于津河水来说,其盐度较低,适度提高盐度有助于抑制藻类水华;氨氮和磷酸盐对藻类生长具有协同促进作用。而对于西区景观河道水,由于其盐度高、可溶性氮磷比过低,添加硝氮可以激发藻类生长,但更高含量的磷则会对藻类生长起到一定的抑制作用。     

镧对黄河包头段水体中混合藻类的影响

选取黄河水体中含量较多的稀土元素镧(La)作为研究对象,以引黄水库富营养化水体中的混合藻类为受试生物,进行藻类的培养试验,探讨了稀土元素对黄河水体中混合藻类生长生理的影响规律。结果表明:低浓度(2 mg/L)La对藻类的生长具有刺激作用;高浓度(50 mg/L)La对藻类的生长具有抑制作用,且浓度越高抑制作用越强;中等浓度(5～10 mg/L)La对藻类生长的刺激与抑制作用受光照强度影响;La在任何浓度下都会改变藻类种群结构、抑制水体中藻类的生物多样性,且浓度越高,抑制作用越强;引黄水库每年3月份藻类的爆发及黄河水体的富营养化可能与水体中的La有关。     

分层取水生态治理水体富营养化方法初探

近年来,城市水库水体富营养化问题日益严重,由此引起的夏季藻类数量增加现象严重影响饮用水质量,威胁居民身体健康。以秦皇岛市石河水库为例,综合其水体富营养化的具体特征和藻类生长与氮磷含量、水体流速的关系,在分析石河水库藻类生长的具体特征后,提出表层取水、加速置换适于藻类生长表层水体、生态治理水体富营养化的方法。     

小浪底水库富营养化趋势分析

通过对小浪底水库水环境、水生生物、污染源等的调查监测,分析了氮、磷、温度、光照度、流速、库区底泥等对库区藻类生长的影响,结果表明:藻类的最适宜生长的温度为25℃,光照度为7 000 lx,水流速度对藻类生长也有一定影响,在流动缓慢的水体中藻类生长比较好。研究了小浪底水库出现富营养化的主要影响因素,并进一步判断了小浪底水库富营养化状态及发展趋势,结果表明:小浪底水库以轻度营养状态为主。     

尖岗水库藻类监测及富营养化调查

水体富营养化而产生藻类生长所带来的一系列的水质恶化问题已成为全球性难题.郑州尖岗水库位于贾鲁河上游饮用水源区,是郑州唯一饮用水备用水源地,系湖泊型水源,为及时掌握其富营养状况及藻类季节性变化规律,初步对其进行了藻类监测和富营养化调查评价和分析.     

流速对藻类生长影响的试验研究

水华的发生除与营养盐、光照等条件有关外,还和水体的流速等水文条件有关.以故宫筒子河为例,分析了推流技术对水体水华的抑制效果,证明增加水体流速可以在一定程度上抑制水华.在此基础上介绍了水体流速对藻类生长影响的试验研究,探讨了水体流速与藻类生长的关系.     

水动力条件对富营养化影响规律探讨

富营养化防治的技术关键，是需要了解抑制藻类生长的外部环境条件及其影响作用规律．基于国内外对气候条件和营养盐条件对藻类生长速率影响研究成果基础上，采用机理分析和实际案例分析相结合的方法，重点探讨了以流速为表征要素的水动力条件对藻类生长速率的影响特点，并且以三峡库区支流大宁河为例，初步建立了流速对藻类生长速率影响规律的经验关系式，为预测三峡库区富营养化演变态势提供基础，进而为有效防治富营养化提供技术支撑．     

Optimal dosing time of acid algaecide for restraining algal growth

Restraining algal growth by algaecide has been studied by many researchers, but the dosing time has not yet been studied. In this study, we examined the appropriate dosing time of algaecide through a series of experiments. In the experiments, the pH value of water is significantly affected by Microcystis aeruginosa, and the variation of the pH value is in favor of the growth of the alga. Therefore, using acid algaecide in the period with maximum pH values, i.e., the stable phase, would change the acidity-alkalinity of the water significantly, and would negatively affect algal growth. Acid algaecide does not eliminate the alga effectively if the acid algaecide is dosed in the logarithmic growth phase. Using acid algaecide in the decline phase after algal bloom not only is unfavorable for eliminating the alga, but also prolongs the decline phase, and even brings about next larger algal bloom.     

Seasonal and spatial variation in algal growth potential and growth-limiting nutrients in a shallow endorheic lake: Lake Pátzcuaro (Mexico)

The present research focused on the functional role of the phytoplankton of an economically important endorheic tropical lake from the perspective of algal growth bioassays. The algal growth potential of the lake water was compared for littoral and pelagic sites during the wet and dry seasons. Algal growth potentials at open waters reached minimum and maximum values following the seasonal alternation of dilution (by rain) and concentration (by evaporation) respectively. Conversely, at southern littoral stations high algal growth responses related to the availability of nutrients from point contamination sites. There was no such effect at nearby offshore sites or elsewhere in the lake which suggests filtration and competitive interactions for these nutrients between phytoplankton and littoral macrophytes. Nitrogen and phosphorus both acted consistently as limiting nutrients at open waters by colimitation. Nitrogen to phosphorus ratios seemed to approach equilibrium where limitation easily shifted to one element or the other temporally and spatially.     

Environmental factors controlling phytoplankton dynamics in a large floodplain river with emphasis on cyanobacteria

Harmful algal blooms are occurring in large river ecosystems and at the mouth of large rivers with increasing frequency. In lentic systems, the chemical and physical conditions that promote harmful algal blooms are somewhat predictable but tracking prevalence and conditions that promote harmful algal blooms in lotic systems is much more difficult. We captured two of the most extreme discharge years within the last 20 years occurring in the Upper Mississippi River, allowing a natural experiment that evaluated how major shifts in discharge drive environmental variation and associated shifts in phytoplankton. Statistical models describing significant environmental covariates for phytoplankton assemblages and specific taxa were developed and used to identify management‐relevant numeric breakpoints at which environmental variables may promote the growth of specific phytoplankton and/or cyanobacteria. Our analyses supported that potentially toxin‐producing cyanobacteria dominate under high phosphorus concentration, low nitrogen concentration, low nitrogen‐to‐phosphorus ratio, low turbulence, low flushing, adequate light and warm temperatures. Cyanobacteria dominated in 2009 when low discharge and low flushing likely led to optimal growth environments for Dolichospermum, Aphanizomenon and Microcystis. Rarely will a single factor lead to the dominance, but multiple positive factors working in concert can lead to cyanobacteria proliferation in large rivers. Certain isolated backwaters with high phosphorus, low nitrogen, warm water temperatures and low potential for flushing could benefit from increased connection to channel inputs to reduce cyanobacterial dominance. Numerous examples of this type of habitat currently exist in the Upper Mississippi River and could benefit from reconnection to channel habitats.     

Phytoplankton community and algal growth potential in Taipinghu Reservoir, Anhui Province, China

An integrated investigation of the community structure and growth potential of algae in Taipinghu Reservoir, Anhui Province, China, was conducted from July 1993 to October 1994. A total of 112 algal species belonging to eight phyla were observed. Green algae were the dominant population, representing 55% of the total recorded taxa. Diatoms and blue‐green algae formed the second and the third largest algal groups, respectively. The total species and population of algae were relatively steady in spring, summer and autumn, but exhibited some variety in winter. Compared to earlier data, the species richness decreased by 36% and the number of genera decreased by 23% over an eight‐year period. The maximum values of the annual mean cell count, biomass and chlorophyll a concentration appeared in summer and the minimum in winter. The algal growth potential of the original water without supplemental nutrients was much lower than that of the control culture, but equal to or a little higher than the control culture which was supplemented with complete nutrients. The study results imply that phosphorus is the limiting nutrient for algal growth and that the trophic status of the reservoir is changing from mesotrophic to eutrophic. Based on these data, some advice on how to manage the reservoir is offered.     

Management of agricultural practices results in declines of filamentous algae in the lake littoral

Filamentous algal cover was quantified during periods of peak biomass from 2001 to 2007 in six littoral macrophyte beds in Conesus Lake, New York (USA). Three of the study sites were adjacent to streams that drained sub-watersheds where extensive agricultural best management practices (BMPs) designed to reduce nutrient runoff were implemented beginning in 2003. Three other study sites were downstream from sub-watersheds where only a few or no BMPs were implemented by landowners. For the sites that received extensive management, comparisons of the Pre-BMP baseline period (2–3 yrs) to the Post-BMP period (4 yrs) revealed that algal cover was statistically lower than baseline in eight of eleven years (72.7%). For the three sites where limited or no management was implemented, the percent cover of filamentous algae was lower than Pre-BMP baseline levels in only three of twelve years (25%). Where major reductions in cover of filamentous algae occurred, positive relationships existed with summer stream loading of nitrate and soluble reactive phosphorus to the nearshore. In some cases only nitrate loading was significantly correlated with percent cover, indicating that the relative importance of nitrogen and phosphorus to algal growth near streams may be determined by the characteristics and land use within each sub-watershed. Agricultural BMPs targeting nutrient and suspended solid runoff can effectively reduce filamentous algal growth locally along the lake littoral zone on a time scale of months to a few years and with moderate commitment of resources. This work offers a new perspective for management of the growing problem of littoral algal growth in the embayments and drowned river mouths of the Great Lakes.     

邻苯二酚和邻苯三酚对藻类化感作用的试验

以藻类细胞的叶绿素a含量变化为指标来分析不同浓度的邻苯二酚和邻苯三酚对蛋白核小球藻以及斜生栅藻生长代谢的化感作用程度,初步确定了邻苯二酚(O-Dihydroxybenzene)和邻苯三酚(Pyrogallol)对两种藻类生长抑制程度最高的投加量,为筛选高效抑藻化感物质及其最佳作用浓度提供了试验依据.     

Seasonal variations of phytoplankton species in Lake Victoria and the influence of iron and zinc ions on the dominant species identified during 2006–2007 studies

The current study was conducted for 2 years (2006 and 2007) during January, April and September to investigate seasonal variations in biological parameters and planktonic biodiversity observed at four sampling sites (MRM, M500, SRM and S500) in Lake Victoria. Blue‐green algae (Cyanophyta) dominated the lakeshore waters of Lake Victoria, comprising 54.1% of the total algal content, compared to 24.4% for diatoms and 14.7% for green algae (Chlorophyta). Euglenophytes and dinoflagellates both constitute <10% of the algal biomass. The algal distribution at the Sango Bay sampling sites, however, is different in that it is dominated by diatoms, in contrast to Murchison Bay, which was dominated by blue‐green algae. This study also investigated the influence of iron (Fe²⁺and Fe³⁺) and zinc (Zn²⁺) ions on four strains of microcystis (CYN 464, CYN 465, CYN 478 and CYN 522) isolated from Murchison Bay in Lake Victoria. The suggestion that iron species and zinc ions might limit phytoplankton growth in Lake Victoria was tested by enriching algal culture media with different metal concentrations. Based on measurements of the algal biomass of four species of Lake Victoria, the algal biomass of the four microcystis strains generally decreased with increased zinc and Fe²⁺ concentrations. The algal biomass of the four strains, however, increased with increased Fe³⁺ concentrations. This response to different metal concentrations provides evidence that high Zn²⁺ and Fe²⁺ ion concentrations limit phytoplankton growth and species distribution. The availability of Fe³⁺ ions is an important selective force on Lake Victoria phytoplankton communities.