鲢鱼、芦台鲌鱼对富营养化水体中藻类的控制作用

利用室内受控生态系统实验,研究鲢鱼和芦台鲌鱼对富营养化水体中藻类的控制作用.对各受控系统中藻类与浮游动物的统计数据及理化指标,进行了相关性分析和非参数检验的统计分析.实验结果显示,在一定密度下放养滤食性鲢鱼足可以起到控藻作用的.一定密度的芦台鲌鱼与水生植物联合养殖也会起到控藻作用.放养鱼类控藻都要在适当的密度下,密度过大或过小都会影响控藻效果.研究还发现,鱼类的放养会使水体中蓝藻在浮游植物中的比例增大.     

富营养化水体中藻类生长限制因素的确定及其应用

在富化营养化的巢湖，围隔实验结果表明磷和其它营养元素不是水体藻类的生长限制因素、藻类生长的正磷酸盐阈值浓度为０．０１９ｍｇ／ｌ，它低于巢湖实际浓度。湖水的矿物性浊度很高，净生产力在一米水深以下呈现负值，数据表明学强在大数时间是藻类生长的限制因素。在巢湖治理过程中，需大幅降低流域内的磷负荷，使湖水平均溶解态总磷浓度从目前的０．０４９ｍｌ／ｌ降到０．０１９ｍｇ／ｌ以下。因此巢湖在治理和恢复是一个缓慢的     

二氧化氯对水中病毒,藻类和浮游动物的失活效果

本文研究了二氧化氯对水中一些主要病毒，藻类和浮游动物的失活效果，以及不同消毒剂投量，接触时间和ｐＨ值等条件下，二氧化氯对水体中一些微生物的杀灭和失活效果。与流氯对比的结果表明：ＣｌＯ２对藻类失活效果优于或相当于液氯；ＣｌＯ２对病毒和浮游动物的失活效果显著优于液氯；ＣｌＯ２可在一广泛的ｐＨ值范围内杀灭微生物。     

浮游动物在生物操纵法除藻中的作用研究

采用室外现场实验和室内受控生态系统实验相结合的方法,研究了富营养化水体中浮游动物对藻类生长的控制作用。对浮游动物与藻类的计数与测量数据,利用SPSS统计软件进行了方差分析(LSD多重比较法)和相关性分析。实验结果显示,总磷含量比总氮含量对浮游动物生长的影响更大。浮游动物与藻类之间呈现显著或极显著相关关系,说明浮游动物群体,尤其甲壳类群体,在适当条件下对藻类群体以及其中的蓝藻有一定的控制作用。适当的鱼类密度下,浮游动物能够起有效的控藻作用,但鱼类密度过高会抑制该作用。底泥在生态系统中起重要作用,能够影响浮游动物对藻类的摄食力。     

人工介质富集附着生物对富营养化水体的净化作用

研究了人工介质富集附着生物对富营养化水体中藻类及氮、磷营养物质的去除特性,以及不同水深、水体流速和溶解氧、温度、pH等理化性质对去除效果的影响.结果表明,在静态水体条件下,组合人工介质富集附着生物对于NH4+ -N、TN、TDN、NO3- -N、TP、TDP和PO43- -P平均去除率分别为98.90%、45.15%、42.78%、38.13%、76.18%、80.11%和87.02%,藻类叶绿素a(Chl-a)含量则降低了63.53%.随着水深的增加,藻类Chl-a含量下降速度减缓,但对氮、磷营养物质的去除影响不大.随着水体流速的增加,即由静态水体转变为流速为200 L·h-1的动态水体,藻类Chl-a含量降低程度有所增加,TP和TDP去除率也有所增加,其中,静态和动态水体中Chl-a含量分别降低了63.53%和72.17%,TP去除率由76.18%增至85.13%,TDP由80.11%增至83.76%;TN去除率由45.15%降至32.02%,TDN由42.78%降至28.73%;对于NO3- -N,静态对照去除率为38.13%,而动态处理去除效果不佳;而NH4+-N和PO43--P去除率变化不大,NH4+-N由98.90%变为98.59%,PO43--P由87.02%变为86.13%.水体DO、温度、pH等理化性质特别是p(DO)对净化效果亦有一定影响.     

富营养化水体降磷对浮游植物群落结构特征的影响

浮游植物是水生态系统中物质循环和能量流动的基础,作为初级生产者,浮游植物的群落结构直接影响着水生态系统的结构和功能。在水产养殖生产中,如何根据养殖生物对生活环境的需求开展精准培水、定向培水,培养养殖生物所需要的浮游植物,在维持养殖水域生态平衡的同时又能为养殖生物提供一定的饵料资源,这一直是摆在水产科技工作者面前的重要难题和研究热点。已有的资料大都是通过添加磷的方式研究磷改变对浮游植物生长的影响,而有关富营养化水体降磷对浮游植物群落结构影响的研究尚未见报道。为此,试验通过向取自富营养化湖泊的水体中加入磷去除剂,采用Pielou均匀度指数、Mcnaughton优势度指数和Shannon多样性指数,研究自然水体中的磷被降低后水体浮游植物群落结构的变化情况。结果表明,所取富营养化水体中共检出绿藻（Chlorophyta）、硅藻（Bacillariophyta）、蓝藻（Cyanophyta）、裸藻（Euglenophyta）、隐藻（Cryptophyta）、甲藻（Pyrrophyta）6门29种（包括变种和变型）;其中绿藻、蓝藻、硅藻、隐藻、裸藻、甲藻分别有7、4、2、1、1种,分别占总种数的24.13%、13.79%、6.90%、3.45%、3.45%。富营养化水体降磷后,虽然试验组和对照组在浮游植物种类组成上没有差异,但浮游植物群落结构特征发生了很大变化,浮游植物数量明显降低,由13 238.8×104cells·L-1降低至3 997.5×104cells·L-1,下降了69.8%;浮游植物优势种从1门（蓝藻（Cyanophyta））6种增加到3门（绿藻（Chlorophyta）、硅藻（Bacillariophyta）、蓝藻（Cyanophyta））12种,优势度指数从97.29%降低至86.30%,优势种门数和优势种种数远远高于对照组,优势度明显低于对照组;同时,浮游植物多样性指数和均匀度分别从1.85和0.38升高至2.60和0.54,显示出试验组浮游植物多样性和均匀度优于对照组。研究表明富营养化水体降磷对浮游植物群落结构产生了明显影响,使群落结构处于更加复杂、完整和稳定的状态。     

扰动对水体富营养化的改善作用

利用人工构建的模拟水体系统,观察搅拌和曝气条件下水体中氮磷含量和形态的变化规律,研究和探讨了扰动对水体富营养化的改善。结果表明：（1）扰动对上覆水体氮的去除效果不明显,但是能够有效促进底泥中氨氮向水体扩散,从而使底泥中氮含量明显降低,运行99 d后,曝气反应器中底泥总氮含量从初始3.46 g.kg-1降至0.68 g.kg-1,仅为对照反应器的1/4;（2）搅拌对上覆水中磷的去除效果最佳,反应器运行期间,总磷的平均去除率为37%左右;（3）扰动能增加底泥中微生物的数量和多样性,为污染物的生物降解提供了良好的基础。合理运用扰动能够提高水中溶解氧含量,改善微生态环境,增加微生物的数量和种类,有利于水体富营养化的改善。     

三峡水库浮游植物群落特征及水体富营养化评价

基于2003—2017年三峡水库浮游植物群落结构、优势种群的变化和2017年水库干支流水质数据,全面分析浮游植物群落结构和演替特征,并运用综合营养状态指数法对水体富营养化程度进行评价。结果表明,三峡水库浮游植物种类丰富,监测期间共鉴定出浮游植物7门62属,细胞密度在7.5×10~4~2.8×10~7cell/L之间变化,Shannon-Wiener多样性指数为1.0~3.0,在α-中污带和β-中污带之间,说明三峡水库水生态环境健康状况相对较好;三峡水库浮游植物季节性演替特征呈硅藻和甲藻向蓝藻和绿藻演替的趋势,年际变化特征分析发现浮游植物密度在2008年175 m实验蓄水后大量增长,且优势藻类由河道型藻类向湖泊型藻类转化。通过监测数据分析,得出三峡水库干流处于中营养状态,支流在春季主要处于轻度富营养状态,秋季支流比春季支流的富营养化程度低,主要处于中营养状态,总氮(total nitrogen,TN)、总磷(total phosphorus,TP)和透明度(transparency,SD)为水质主要影响因子。     

二氧化氯对水中病毒、藻类和浮游动物的失活效果

本文研究了二氧化氯对水中一些主要病毒、藻类和浮游动物的失活效果,以及在不同消毒剂投量、接触时间和pH值等条件下,二氧化氯(ClO_2)对水体中一些微生物的杀灭和失活效果.与液氯对比的结果表明:ClO_2对藻类失活效果优于或相当于液氯;ClO_2对病毒和浮游动物的失活效果显著优于液氯;ClO_2可在一广泛的pH值范围内杀灭微生物.此外,还从理论上初步探讨了ClO_2对病毒的失活机理.研究结果表明,ClO_2是一种优良的液氯替代消毒剂,这对开展ClO_2的研究及其应用有重要意义.     

无磷洗衣粉并非控制水体富营养化的灵丹妙药

很多人认为，使用无磷洗衣粉便能有效解决令人烦恼的“水华”或“赤潮”问题。然而，无论是西方国家长达20年的实践经验，还是我国目前面临的现状显示，无磷洗衣粉对遏制水体富营养化现象作用并不十分明显!究其原因，面源污染和生活污水中的其它磷来源才是构成水体磷负荷的主要来源。因此，在国内外普遍兴建污水处理厂的前提下，是否有必要以洗涤效果不佳、可能会产生新的环境问题的无磷洗衣粉替代传统洗衣粉目前正遭到国外一些有识之士质疑。文章介绍了国外这方面的情况，并总结性地提出了我国在此方面应注意的问题。     

Grazing of phytoplankton by copepods in eastern Antarctic coastal waters

Chlorophyll a, primary productivity and grazing by copepods on phytoplankton were measured in the upper water column during the summer of 1994/1995 at a coastal site near Davis Station, East Antarctica. Chlorophyll a was at a maximum in mid-December, then dropped markedly as the coastal fast ice melted and broke‐out. Phytoplankton biomass increased again from mid‐ to late‐February. Copepods accounted for at least 65% of zooplankton biomass in the water column before sea ice break‐out, whereas larval polychaetes and ctenophores dominated after ice break‐out. Oncaeacurvata was the numerically dominant species throughout the study. The highest grazing rate (8.7 mg C␣m⁻³␣d⁻¹) was recorded on 21 December when O.␣curvata accounted for 64% of the total. Grazing had decreased markedly by 28 December (0.9 mg C m⁻³ d⁻¹); again O. curvata accounted for over 50% of the total ingested. Copepod grazing increased after ice break-out until the last experiment on 20 February (⋍5 mg C␣m⁻³␣d⁻¹). The main species responsible for grazing during this period were O. curvata, Oithonasimilis, Calanoidesacutus and unidentified copepod nauplii. It was estimated that copepods removed between 1 and 5% of primary productivity. Received: 11 October 1996 / Accepted: 22 October 1996     

Nocturnal movements of phototactic zooplankton in shallow waters

Downwardly directed light-traps were used by night, over seagrass and coral sand to investigate the existence and significance of nocturnal peaks in phototactic zooplankton. Samples each half-hour from sunset to sunrise showed that small invertebrates, mostly copepods, were trapped in large numbers once or twice a night. Each period of high catches lasted only 1 to 2 h and was often associated with periods of failing natural light (evening twilight, moonset). This pattern and its variations are explained in terms of nocturnal vertical migration, in which plankton move towards light in response to decreasing light intensity, move away from light in response to increasing light intensity, and disperse at constant light intensity. Some morning peaks are unexplained.     

Aspects of a zooplankton,phytoplankton, phosphorus system

In this paper a three-dimensional dynamical system which models the three-species system made up of phytoplankton, zooplankton and organic phosphorus nutrient in a lake environment is studied. The system is part of a more general limnological model for eutrophic lakes and impoundments which has been developed by Battelle Northwest Laboratories. It is shown that this system, henceforth referred to as Z-P-P, has a phase portrait comprised of a plane portrait embedded in the three-dimensional space R³ as an “attractor”.¹ Under a small perturbation of the nutrient equation it is shown that the system is essentially a classical Volterra-Lotka system embedded in a three-dimensional phase space R³.The system derived from Z-P-P by the addition of a term to the nutrient equation which represents the organic phosphorus contribution of dying phytoplankton is also considered. The equilibria of this system are studied and what can be deduced of the phase portrait is compared with that of the above systems. It is found that these phase portraits are qualitatively indifferent to the form of the growth rate functions for zooplankton and phytoplankton provided they are monotone increasing. Some discussion about the stability of these systems is included. Throughout this paper results are interpreted in limnological terms.     

Apparent predation on ichthyoplankton by zooplankton and fishes in nearshore waters of southern California

Plankton collected at discrete depths in Santa Monica Bay, California, USA, during January 1982 were examined for fish eggs and larvae that had been attacked or consumed by zooplankton. The bongo net remained open for only 3 min and samples were preserved within 5 min of capture. Juvenile and adult fishes that had been captured by otter trawl and preserved within 20 min of capture were examined for ingested fish eggs and larvae. Three copepods (Corycaeus anglicus, Labidocera trispinosa, and Tortanus discaudatus), one euphausid larva (Nyctiphanes simplex), one amphipod (Monoculoides sp.), and an unidentified decapod larva were found attached to fish larvae in the preserved plankton samples (attachment to 23% of the fish larvae was observed in one sample). Overall, about 5% of the white croaker (Genyonemus lineatus) larvae and 2% of the northern anchovy (Engraulis mordax) larvae had attached zooplankton predators. Most fish larvae with attached zooplankton predators were small. We found no indication of zooplankton predation on fish eggs. Few fish eggs and larvae were found in the digestive tracts of juvenile or adult fishes, and the ingested fish larvae were relatively large. The discussion considers apparent preyspecificity of the zooplankton predators as well as potential biases that may be associated with preserved samples collected by nets.     

Microzooplankton grazing and selectivity of phytoplankton in coastal waters

Microzooplankton grazing activity in the Celtic Sea and Carmarthen Bay in summer 1983 and autumn 1984 was investigated by applying a dilution technique to high-performance liquid chromatographic (HPLC) analysis of photosynthetic pigments in phytoplankton present within natural microplankton communities. Specific grazing rates on phytoplankton, as measured by the utilisation of chlorophyll a, were high and varied seasonally. In surface waters during the autumn, grazing varied between 0.4 d^-1 in the bay and 1.0 d^-1 in the Celtic Sea, indicating that 30 and 65% of the algal standing stocks, respectively, were grazed daily. Grazing rates by microzooplankton within the thermocline in summer suggest that 13 to 42% of the crop was grazed each day. Microzooplankton showed selection for algae containing chlorophyll b, in spite of a predominance of chlorophyll c within the phytoplankton community. Changes in taxon-specific carotenoids indicated strong selection for peridinin, lutein and alloxanthin and selection against fucoxanthin and diadinoxanthin. This indicates a trophic preference by microzooplankton for dinoflagellates, cryptophytes, chlorophytes and prasinophytes and selection against diatoms, even when the latter group forms the largest crop within the phytoplankton. Interestingly, those algal taxa preferentially grazed also showed the highest specific growth-rates, suggesting a dynamic feed-back between microzooplankton and phytoplankton. Conversion of grazing rates on each pigment into chlorophyll a equivalents suggests firstly, that in only one experiment could all the grazed chlorophyll a be accounted for by the attrition of other chlorophylls and carotenoids, and secondly that in spite of negative selection, a greater mass of diatoms could be grazed by microzooplankton than any other algal taxon. The former may be due either to a fundamental difference in the break-down rates of chlorophyll a compared to other pigments, or to cyanobacteria forming a significant food source for microzooplankton. In either case, chlorophyll a is considered to be a good measure of grazing activity by microzooplankton.     

Numerical behavior of a zooplankton,phytoplankton and phosphorus system

Several numerical features of a three-dimensional dynamical system which models the three species system made up of phytoplankton, zooplankton and organic phosphorus nutrient in a lake environment are presented. Certain properties of this system, such as the existence of limit cycles, are demonstrated numerically. It is shown that in certain time domains the system may be stiff, thus requiring the use of suitable algorithms.     

丙烯酰胺对水环境中典型微藻的毒性效应

作为可疑致癌物,丙烯酰胺(acrylamide,AM)是目前各国政府和广大民众普遍关注的重要污染物.为探究AM对水体生物的毒性效应及可能存在的生态风险,本文以海洋微藻东海原甲藻(Prorocentrum donghaiense)和淡水微藻莱茵衣藻(Chlamydomonas reinhardtii)为研究对象,采用室内培养法,测定了不同暴露浓度的AM对2种微藻生长、形态和生理状态的影响.结果显示,AM对2种藻类生长均有显著的抑制作用(P0.05),96 h半抑制质量浓度(EC_(50))分别为22.79 mg·L~(-1)和161.8 mg·L~(-1);最高无抑制浓度(NOEC)分别为1.04 mg·L~(-1)和9.84 mg·L~(-1).不同微藻对AM胁迫的响应存在较大的差异性,与莱茵衣藻相比,东海原甲藻对AM更敏感.扫描电镜(SEM)和透射电镜(TEM)结果显示,当受到AM影响时,2种藻细胞严重变形,表现出塌陷、质壁分离、空泡数量增多和叶绿体片层结构少量断裂等现象;叶绿素含量和F_v/F_m(PSⅡ最大光化学量子产量)测试表明AM可以通过破坏微藻的光合系统而抑制光合作用.AM对东海原甲藻属于中毒性物质,对莱茵衣藻属于低毒性物质.     

Diel changes in phytoplankton photosynthetic efficiency in Brackish waters

From 18 to 23 September 1974, investigations on the diel changes in phytoplankton were carried out in the Baltic Sea. Every 4 h, water samples were collected from 2 and 15 m, and PO₄, chlorophyll a, temperature, salinity, pH, phytoplankton composition and phytoplankton light photosynthesis relationship were determined. Continuous measurements of surface irradiance and some estimations of zooplankton were also made. P ^B (photosynthesis per unit chlorophyll a at low light levels of 2·10^-2 cal cm^-2 min^-1) revealed only random variation during the sampling period, i.e., 1.0 to 1.6 mg C (mg chlorophyll a)^-1 h^-1. P _m ^B (Light-saturated photosynthesis per unit of chlorophyll a) displayed pronounced diel fluctuations with the highest value of about 6 mg C (mg chlorophyll a)^-1 h^-1 around noon, and the lowest value of about 2.5 mg C (mg chlorophyll a)^-1 h^-1 during the night, during which latter period the value of P _m ^B was more or less constant. Reasons for the diel fluctuations are discussed, and an equation which describes these fluctuations is proposed. Using this equation, the daily phytoplankton production estimated in incubators by a previously described method can be corrected for the time of day at which samples are collected.     

罗非鱼对富营养型水体中沉水植物苦草的影响

通过室外模拟实验,分别设置罗非鱼组和无鱼对照组的两组处理,研究了尼罗罗非鱼（Oreochromis niloticus）对富营养型水体中沉水植物苦草（Vallisneria spiralis）的影响。结果表明：罗非鱼显著地增加了水中总氮和总磷的质量浓度,同时浮游植物的生物量（叶绿素a）也明显增加;罗非鱼组中的附着藻类的生物量却显著低于无鱼的对照组;罗非鱼组中苦草的相对生长率为-10mg·g-1·d-1,显著低于对照组中苦草的相对生长率7mg·g-1·d-1。罗非鱼的直接牧食可能是苦草生物量降低的主要原因。研究说明,过高的罗非鱼密度会导致沉水植被退化,要保持沉水植被为优势的湖泊清水态,必须控制罗非鱼密度。     

Phosphorus dynamics associated with phytoplankton blooms in eutrophic Mikawa Bay,Japan

Changes in the phosphorus components of the particulate matter in seawater were studied in the eutrophicated waters of Mikawa Bay, Japan, during summer 1981. The contents of particulate phosphorus and hot-water extractable intracellular phosphorus displayed remarkable changes associated with phytoplankton blooms caused by wind-induced or upwelling-associated nutrient enrichment from the bottom water layers. Nanoplankton <10 m accounted for much of the particulate phosphorus (70 to 79% in June and July, and 44 to 78% in August and September); the contribution of large-sized phytoplankton >25 m varied from 9 to 49%, the peak values being attained under red-tide conditions. The capacity for phosphorus storage in cells was low in nanoplankton cells, high in large phytoplankton species. Differences in rates of phosphorus storage and growth between nanoplankton and large phytoplankton accounted for fluctuations in particulate phosphorus which were closely associated with fluctuations in phytoplankton blooms in Mikaw Bay.