生物胺对赤潮藻生长的影响作用初探

选取东海赤潮高发区常见的两种甲藻[东海原甲藻(Prorocentrum donghaiense)、塔玛亚历山大藻(Alexandrium tamarense)]和两种硅藻[中肋骨条藻(Skeletonema costatum)、海链藻(Thalassiosirasp.)],以2-苯基乙胺、腐胺、亚精胺、精胺四种赤潮水体中常见的生物胺为因素,设置0、5、25、100nmol/L四个浓度水平,进行L16(45)正交添加培养实验。根据Logistic生长模型进行曲线拟合,分析得到的生长参数。结果显示,不同的生物胺对各赤潮藻生长影响的大小、趋势均存在差异。其中,2-苯基乙胺对四种赤潮藻的生长影响最显著。高浓度的2-苯基乙胺对中肋骨条藻的生长具有明显的抑制作用,对塔玛亚历山大藻的生长具有明显的促进作用。多胺物质(腐胺、亚精胺和精胺)对甲藻(东海原甲藻和塔玛亚历山大藻)生长的促进作用大于硅藻(海链藻和中肋骨条藻)。多胺中的亚精胺对塔玛亚历山大藻和海链藻的生长影响最大,精胺对东海原甲藻和中肋骨条藻的生长影响最大。多胺可能是2010年东海赤潮由中肋骨条藻向东海原甲藻演替的一个诱导因素,其中精胺可能发挥的作用较大。     

多效唑对2种海洋微藻生长和抗氧化酶活性的影响

运用实验生态学和生物化学的方法,研究了多效唑对青岛大扁藻(Platymonas helgolandica)和绿色巴夫藻(Pavlova viridis)生长和抗氧化酶活性的影响.结果表明:低浓度(≤5 mg/L)多效唑能促进绿色巴夫藻的生长,与对照组相比,多效唑处理组的干重、叶绿素a、可溶性糖和蛋白质含量均有所增加(p<0.05),而低浓度(≤5 mg/L)多效唑对青岛大扁藻的生长无明显影响;高浓度(≥15 mg/L)多效唑可显著抑制青岛大扁藻和绿色巴夫藻的生长,多效唑处理组的干重、叶绿素a、可溶性糖和蛋白质含量均低于对照组(p<0.05).多效唑对青岛大扁藻和绿色巴夫藻的96 h-EC50值分别是28.6 mg/L和24.9 mg/L. 2种微藻经不同浓度多效唑处理后,细胞内抗氧化防御系统的关键性酶超氧化物歧化酶(superoxide dismutase, SOD)和过氧化物酶(peroxidase, POD)均表现为低浓度(≤5 mg/L)的诱导作用和高浓度(≥15 mg/L)时的抑制作用;不同浓度多效唑处理后,2种微藻细胞内过氧化氢酶(catalase, CAT)活性均降低.     

翡翠贻贝对塔玛亚历山大藻的摄食及毒素积累的初步研究

塔玛亚历山大藻是一种可产生PSP毒素的海洋微藻，通过室内摄食实验，初步研究了厦门港水产养殖动物翡翠贻贝对塔玛亚历山大藻的滤食率与光照度、温度、藻液浓度等因素的关系，并对比了翡翠贻贝对其它饵料微藻的摄食压力．同时对比了不同细胞密度的塔玛亚历山大藻浓度对翡翠贻贝毒素累积的影响．     

Cd2+胁迫对6株微藻生长及叶绿素荧光特性的影响

研究了不同浓度的Cd2+胁迫不同时间(24h、48h、72h和96h)后,6株微藻(绿色巴夫藻Pavlova viridis、等鞭金藻塔溪堤品系Tahitian Isochrysis galbana、小球藻Chlorella sp.、微绿球藻Nannochloris oculata、雨生红球藻Haematococus pluvialis和塔胞藻Pyramidomonas sp.)生长及叶绿素荧光特性的变化情况.测定的主要参数有:PSII的最大光能转化效率(Fv/Fm)、PSII的潜在活性(Fv/Fo)、PSII的实际光能转化效率(Yield)、相对光合电子传递效率(rETR)、细胞密度和叶绿素相对含量.研究结果表明,Cd2+胁迫下6株微藻的荧光参数Fv/Fm、Fv/Fo、Yield、rETR、细胞密度和叶绿素相对含量均与Cd2+浓度呈显著的负相关,均随着Cd2+浓度的增加而降低.胁迫时间对各荧光参数也有显著影响.随着胁迫时间的延长,绿色巴夫藻的Fv/Fm、Yield和rETR逐渐下降,Fv/Fo先下降后上升,至72h时又有所下降;等鞭金藻塔溪堤品系和微绿球藻的Fv/Fm、Fv/Fo、Yield和rETR随着胁迫时间的延长均逐渐下降;小球藻和雨生红球藻的上述荧光参数先下降,之后分别在48h和72h时逐渐上升;塔胞藻的上述荧光参数则先上升后下降.在Cd2+胁迫下,6株微藻细胞密度和叶绿素相对含量也显著降低,随着胁迫时间的延长,细胞密度和叶绿素相对含量下降的幅度也逐步增大.相关分析结果表明,6株微藻的叶绿素相对含量与细胞密度均呈极显著的正相关关系.通过细胞密度计算出来的Cd2+对6株微藻96h的半抑制浓度(96h-EC50)分别为绿色巴夫藻(151.538μmol/L),等鞭金藻塔溪堤品系(14.161μmol/L),小球藻(17.150μmol/L),微绿球藻(3.498μmol/L),雨生红球藻(15.205μmol/L),塔胞藻(19.722μmol/L),因此6株微藻对Cd2+的耐受性大小顺序为:绿色巴夫藻>塔胞藻>小球藻>雨生红球藻>等鞭金藻塔溪堤品系>微绿球藻.     

四溴双酚A对7种海洋微藻的急性毒性

本文研究了四溴双酚A(TBBPA)对7种海洋微藻(微拟球藻、塔胞藻、亚心形扁藻、牟氏角毛藻、三角褐指藻、湛江等鞭金藻、等鞭金藻塔溪堤品系)的急性毒性。分析了不同质量浓度TBBPA暴露下7种微藻的相对生长率、抑制率,结果显示,7种海洋微藻对TBBPA的敏感性不同,存在明显的时间—剂量效应。采用概率单位—浓度对数法得到TBBPA对牟氏角毛藻、微拟球藻、等鞭金藻塔溪堤品系、湛江等鞭金藻、塔胞藻的96h半效应浓度分别为2.59、2.64、4.23、4.35和6.71mg·L-1,均属于高毒性。同时发现牟氏角毛藻在2.44mg·L-1的TBBPA作用下96h抑制率为54.72%,微拟球藻在3.456mg·L-1的TBBPA作用下96h抑制率为70.27%,等鞭金藻塔溪堤品系在6mg·L-1的TBBPA作用下96h抑制率为76.64%,湛江等鞭金藻在2.83mg·L-1的TBBPA作用下96h抑制率为39.24%,塔胞藻在9.83mg·L-1的TBBPA作用下96h抑制率为54.21%,三角褐指藻在浓度为9.83mg·L-1的TBBPA作用下96h抑制率为22.84%,亚心形扁藻在浓度14.6mg·L-1的TBBPA作用下96h抑制率仅为14.11%。结果显示,微拟球藻和牟氏角毛藻对TBBPA最敏感,可以作为潜在的生物指示物。     

蒽与苯并[a]芘对海洋微藻致毒影响的比较研究

新月菱形藻 ,球等鞭金藻 870 1和亚心形扁藻 ,分别用不同浓度的蒽和苯并 [a]芘胁迫72 h,测定三种藻的生长速率 ,叶绿素 a含量。实验表明 ,三种微藻对蒽的敏感性由高到低依次为新月菱形藻、球等鞭金藻 870 1和亚心形扁藻 ,它们 72 h的半抑制浓度 EC50 分别是 0 .0 6 0 mg/L、0 .0 6 5mg/L和 0 .0 94 mg/L。而对苯并 [a]芘的敏感性由高到低依次为亚心形扁藻、新月菱形藻和球等鞭金藻 870 1,它们的 72 h· EC50 分别是 0 .0 76 mg/L、0 .0 88mg/L 和 >0 .10 mg/L(在本实验范围内未测到 )。叶绿素 a含量与各自的相对增长率呈一定的正相关。不同的海洋微藻对蒽和苯并 [a]芘的敏感性不同。     

网状原角藻化感作用的初步研究

为明确海洋甲藻——网状原角藻(Protoceratium reticulatum)对海洋微藻的化感作用,揭示其化感物质作为植物源抑藻剂的开发潜能,本文探讨了网状原角藻藻细胞和无细胞滤液对几种海洋微藻——东海原甲藻(Prorocentrum donghaiense)、拟旋链角毛藻(Chaetoceros pseudocurvisetus)、米氏凯伦藻(Karenia mikimotoi)和赤潮异弯藻(Heterosigma akashiwo)生长的影响,并进一步选取东海原甲藻和赤潮异弯藻作为受体藻种,以塔玛亚历山大藻(Alexandrium tamarense)作为阳性对照,比较了2种甲藻的藻细胞培养液和无细胞滤液对东海原甲藻、赤潮异弯藻生长的影响差异。通过比较发现,网状原角藻的无细胞滤液比塔玛亚历山大藻能更明显的抑制东海原甲藻和赤潮异弯藻的生长,尤其是对东海原甲藻,基本阻断其生长。     

金属离子对中肋骨条藻的胁迫效应及叶绿素a 合成的影响

研究中肋骨条藻(Skeletonema costatum)生长对不同质量浓度的5种金属离子胁迫的响应,探讨5种金属离子对中肋骨条藻叶绿素a合成的影响.结果显示:生长方面,中肋骨条藻对Cd2+和Ba2+的响应较明显,培养至第10天,Cd2+质量浓度为1、10 mg/L组生长量仅有对照组的59％及43.6％; Ba2+质量浓度为2 mg/L组到第10天是对照组的69.4％,而0.5 mg/L组超过对照组38.9％;中肋骨条藻对其他金属离子的胁迫响应不明显;叶绿素合成方面,Cd2+质量浓度为1 mg/L时,叶绿素a合成量达最高,高于对照组157％;而Ba2+质量浓度为0.5、1 mg/L时,超出对照组的116％和483％;其他金属离子对中肋骨条藻叶绿素a合成均起抑制作用,各个质量浓度组均低于对照组,其中pb2+质量浓度为0.3 mg/L、Mn2+质量浓度为1 mg/L及Li+质量浓度为0.1 mg/L时,叶绿素a含量达最低值,仅为对照组的34.1％、37.5％和17.6％;结论是质量浓度为0.5 mg/L的Ba2+可促进中肋骨条藻的生长及叶绿素的合成,对其产业化规模培养具有重要意义.     

双壳类清滤率在海洋污染物毒性研究中的应用

以海湾扇贝(Argopectenirradians)和紫贻贝 (Mytilusedulis)的清滤率为指标 ,研究了金矿废水及其组分、三苯基氯化锡及塔玛亚历山大藻的毒性 ,结果表明金矿废水及其主要组分丁级黄药、CN-和重金属Cd2 +、Cu2 +、Zn2 +对海湾扇贝清滤率的半抑制浓度EC50 分别为40.6 %、7.52、0.226、0.189、0.02、1.10mg/L ;三苯基氯化锡对海湾扇贝的半抑制浓度EC50 为4.86×10-9g/L;塔玛亚历山大藻能抑制紫贻贝的清滤率,半抑制浓度EC50为6000cells/ml。由以上结果可见 ,双壳类清滤率能快速、敏感地反应污染物的影响 ,是海洋污染物毒性研究的一个良好指标。     

对二甲苯和苯乙烯对海洋微藻生长和光合能力的影响

为了探讨对二甲苯和苯乙烯对海洋微藻的毒性效应,本研究以三角褐指藻和亚心形扁藻为材料,分别比较了不同浓度的对二甲苯和苯乙烯胁迫对微藻生长以及叶绿素含量的影响,并计算对二甲苯和苯乙烯对三角褐指藻和亚心形扁藻96hEC50。研究表明,对二甲苯和苯乙烯对三角褐指藻和亚心形扁藻生长的抑制呈显著的剂量-效应关系,对二甲苯和苯乙烯对三角褐指藻96hEC50分别为60.20mg/L和47.82mg/L,对亚心形扁藻的96hEC50值分别为26.49mg/L和85.62mg/L,相比而言,三角褐指藻对苯乙烯敏感,而亚心形扁藻对对二甲苯更为敏感。同时研究还发现,对二甲苯和苯乙烯胁迫下,试验微藻的叶绿素含量均随处理浓度以及处理时间而显著降低。这些结果为评估对二甲苯和苯乙烯对海洋微藻的毒性效应提供了依据。     

氮磷营养盐与有机汞联合作用对微氏海链藻生长的影响

探讨在高营养盐（氮、磷、硅分别为浮游植物生长的营养盐阚值≥40、50、9倍）条件下，氮浓度及氮磷摩尔比值[n（N）／n（P）]变化、汞（甲基汞和乙基汞）对微氏海链藻（Thalassiosira weissflogii）生长的影响。结果表明，高营养盐区海链藻的生长遵循营养盐限制的唯一因子论；氮浓度和氮磷比提高促进生长，当n（N）／n（P）=64则呈抑制效应；生长初期，甲基汞和乙基汞均产生毒性抑制作用，生长中后期，适量甲基汞（浓度≤1．0μg／L）、乙基汞（浓度≤0．5μg／L）却呈兴奋效应，促进生长；汞形态不同，剂量-效应关系不同。氮和有机汞是海链藻生长的刺激因子。适度有机汞污染与氮富营养化对微氏海链藻的生长产生协同效应。     

不同适温海洋富油微藻在富碳培养条件下的油脂积累特性研究

本实验分别针对3株低温藻株:微拟球藻Nannochloropsis sp.ZL-12、四爿藻Tetraselmis chui ZL-33和小球藻Chlorellasp.ZL-45,3株中温藻株:球等鞭金藻Isochrysis galbana CCMM5001、等鞭金藻Isochrysis sp.CCMM5002和微拟球藻Nannochloropsis sp.CCMM7001,3株高温藻株:微拟球藻Nannochloropsis sp.JN1、绿色巴夫藻Pavlova viridis JN2和海洋小球藻Chlorellasp.JN3,研究了在通入0.03%(空气)、5%、10%3个CO2浓度梯度条件下的生长特性,同时考察了其总酯及中性脂的累积情况。结果显示,富碳培养有利于不同温度条件下9株藻株的生长,除微拟球藻Nannochloropsis sp.CCMM7001最适生长的CO2浓度为5%外,其余8株藻株最适生长的CO2浓度均为10%。在低温和高温条件下,6株海洋富油微藻在通入10%CO2时具有最大生物量产率,在中温条件下球等鞭金藻和等鞭金藻在通入10%CO2时获得最大生物量产率,而微拟球藻在通入5%时获得最大生物量产率,随着CO2浓度的增加,9株藻株的总脂含量和中性脂含量有明显提高。低温和中温藻株的总脂含量高于高温藻株的总脂含量,从中性脂的累积规律来看,9株藻株均在平台期的累积达到最大值,GC-MS分析结果表明,9株微藻适合制备生物柴油的C14~C18系脂肪酸相对含量在不同CO2条件下基本保持不变,维持在90%左右。实验结果显示,所研究的藻株作为富油高固碳优良藻株,具备用于海洋生物质能耦合CO2减排开发的潜力。     

Effect of Mercury Chloride on the Chlorophyl <Emphasis Type="Italic">a</Emphasis> and Pheophytin Content in Marine Microalgae: Measuring the Flow of Autotrophic Phytoplankton Using Sediment Traps Data

The present work aimed to study the influence of mercuric chloride (HgCl₂) on pigment content (chlorophyll a and pheophytin) in sediment traps on the basis of experimental data. The marine microalgal cultures of Conticribra weissflogii (Mediophyceae), Tetraselmis viridis (Chlorodendrophyceae), Amphidinium carterae (Dinophyceae), Nannochloropsis sp. (Eustigmatophyceae) were used. The obtained results revealed that the influence of mercury on pigment content as well as on photosynthetic activity was different in different species. The considerable decrease in phytopigments content was observed in Amphidinium carterae and Conticribra weissflogii, while the proportion of pheophytin increased. The pigment content of Tetraselmis viridis was not different from the control line, while for Nannochloropsis sp. the increase in pigment concentration was noticed. The complete immediate inhibition of photosynthetic activity was observed in Conticribra weissflogii, Tetraselmis viridis, Amphidinium carterae, while Nannochloropsis sp. responded only after 24 h of exposition. The pigment degradation rate was almost the same for diatoms and dinoflagellates. The equation for estimating the phytopigments content in sediment traps, that takes into consideration the exposition time, is proposed.     

纳米TiO2 对海洋生源要素含量及威氏海链藻生长的影响

探讨不同质量浓度纳米TiO2(0,4,8,12,16,20 mg/L)对海洋生源要素(N,P,Si,Fe)含量及威氏海链藻(Thalassiosira weissflogii)生长的影响。实验结果表明:随纳米二氧化钛浓度增大,对海洋生源要素的吸附率有不同程度的提高,海洋生源要素含量下降,对磷和铁的影响最为明显;纳米二氧化钛吸附对氮磷比和硅磷比影响很大,氮磷比为68~126,硅磷比为74~135,而对硅氮比影响很小基本维持在1。纳米二氧化钛对威氏海链藻生长有明显抑制,并存在剂量—效应关系,与海洋生源要素含量影响存在相关性。     

环烷酸对淡水微藻生理生化特征的影响

环烷酸是高酸原油的主要污染组分,对水生生态系统造成潜在威胁。在不同浓度环烷酸处理下对两种模式淡水微藻——莱茵衣藻(Chlamydomonas reinhardtii)和小球藻(Chlorella vulgaris)进行了96 h的连续培养,研究了环烷酸胁迫对两种淡水微藻种群及生理生化特征的影响,旨在为水生生态系统中环烷酸污染的生态风险预测与规避提供前瞻性的研究资料。研究结果表明,低浓度环烷酸(0.5～4 mg/L)会刺激淡水微藻的种群增长,而高浓度环烷酸(8～16 mg/L)会抑制淡水微藻的种群增长,造成急性毒性损伤。低浓度环烷酸处理下两种微藻叶绿素a含量上升,脂质积累,高浓度环烷酸处理下两种微藻叶绿素a含量下降而多糖含量上升,推测环烷酸剂量可能会影响淡水微藻能量存储方式。两种微藻在环烷酸胁迫下均会受到氧化损伤,造成活性氧(reactive oxygen species,ROS)含量上升,两种微藻抗氧化酶超氧化物歧化酶(superoxide dismutase,SOD)和过氧化氢酶(catalase,CAT)对环烷酸处理具有种属差异;高浓度环烷酸对淡水微藻的急性损伤具有时间效应,毒性随...     

Ecological consequence of the introduction of the polychaete Marenzelleria cf. viridis into a shallow-water biotope of the northern Baltic Sea

Effects of the North American polychaete Marenzelleria cf. viridis on a simple shallow-water benthic community of the northern Baltic Sea were studied in a field experiment combining natural densities of dominating macrofaunal species. The presence of M. cf. viridis increased benthic production (chlorophyll a) and reduced the survival of the native polychaete Nereis diversicolor. Adult Macoma balthica caused a significant mortality on M. cf. viridis whereas adult Cerastoderma glaucum had no effect on M. cf. viridis. We suggest that the competitive interactions between M. cf. viridis and M. balthica are a possible key factor determining the distribution pattern of M. cf. viridis in the Baltic Sea.     

重金属锌对海洋微藻藻源氨基酸产出的影响

锌是海洋微藻生长必需的金属元素,低浓度时可促进微藻的生长,而在高浓度时则表现为抑制其生长。受人类活动的影响,海洋中锌有富集增加的趋势,从而会对海洋微藻的生长产生影响。本论文探究了锌离子以及纳米氧化锌对硅藻中肋骨条藻(Skeletonemacostatum)和新月菱形藻(Nitzschia closterium)生长的影响,特别是对藻源氨基酸产生的影响,结果发现:纳米金属颗粒会通过释放离子的形式抑制海洋浮游植物的生长,中肋骨条藻比新月菱形藻对锌的响应更敏感。锌离子和纳米氧化锌可通过抑制浮游植物的生长来减少氨基酸的释放量和改变藻源氨基酸的种类,从而可能会对海洋氮循环过程产生影响。     

The determination of heme b in marine phyto- and bacterioplankton

A method for the quantification of heme b in marine phyto- and bacterioplankton is described. Heme b was extracted from filtered cells using a solution of 2.5% octyl β-glucopyranoside in 0.02 M ammonium hydroxide. The extract was analysed by high performance liquid chromatography diode array spectrophotometry. Maximum absorbance for heme b was at 400 nm. Heme b was separated from other pigments using a polystyrene divinyl benzene stationary phase and a gradient elution programme with 0.1% (v:v) nonafluoropentanoic acid in water and 50:50 (v:v) isopropanol:acetonitrile as the mobile phases. Heme b was quantified using Fe (III) protoporphyrin IX chloride (hemin) standards. The detection limit, calculated from 3 × s.d. of the lowest standard was 0.08 pmol or 1.57 nM with a 50 μL injection volume. The first data for heme b in marine phyto- and bacterioplankton are reported. Heme b contents are reported for the eukaryotes Thalassiosira weissflogii, Thalassiosira oceanica, Dunaliella tertiolecta and Emiliania huxleyi, and the prokaryotes Synechococcus WH8102, WH7803, RCC307, Erythrobacter litoralis, Roseobacter denitrificans and Vibrio natriegens. For T. weissflogii, T. oceanica, D. tertiolecta and E. huxleyi cellular heme b concentrations varied between 12 and 60 μmol L^− 1 and chlorophyll a to heme b ratios varied between 216 and 309.     

Experimental studies on dimethylsulfide (DMS) and dimethylsulfoniopropionate (DMSP) production by four marine microalgae

The production of dimethylsulfide (DMS) and dimethylsulfoniopropionate (DMSP) by marine microalgae was investigated to elucidate more on the role of marine phytoplankton in ocean-atmosphere interactions in the global biogeochemical sulfur cycle.Axenic laboratory cultures of four marine microalgae–Isochrysis galbana 8701,Pavlova viridis,Platymonas sp.and Chlorella were tested for DMSP production and conversion into DMS.Among these four microalgae,Isochrysis galbana 8701 and Pavlova viridis are two species of Haptophyta,while Chlorella and Platymonas sp.belong to Chlorophyta.The results demonstrate that the four algae can produce various amounts of DMS(P),and their DMS(P) production was species specific.With similar cell size,more DMS was released by Haptophyta than that by Chlorophyta.DMS and dissolved DMSP (DMSPd) concentrations in algal cultures varied significantly during their life cycles.The highest release of DMS appeared in the senescent period for all the four algae.Variations in DMSP concentrations were in strong compliance with variations in algal cell densities during the growing period.A highly significant correlation was observed between the DMS and DMSPd concentrations in algal cultures,and there was a time lag for the variation trend of the DMS concentrations as compared with that of the DMSPd.The consistency of variation patterns of DMS and DMSPd implies that the DMSPd produced by phytoplankton cells has a marked effect on the production of DMS.In the present study,the authors’ results specify the significant contribution of the marine phytoplankton to DMS(P) production and the importance of biological control of DMS concentrations in oceanic water.     

Allelopathic interactions between the macroalga Ulva pertusa and eight microalgal species

Growth of Ulva pertusa and eight microalgal species, Heterosigma akashiwo, Skeletonema costatum, Tetraselmis subcordiformis, Nitzschia closterium, Chaetoceros gracile, Chroomonas placoidea 1967, Isochrysis galbana 8701, and Alexandrium tamarense, was examined in a series of batch, semi-continuous and isolated co-cultures (U. pertusa and one microalgal species). The results of the experiments with co-cultures confirmed the secretion of allelopathic substances by U. pertusa. Growth was significantly (p<0.05) suppressed in each of the macroalgal species in batch co-cultures, nutrient replete semi-continuous co-cultures and isolated co-cultures. The percentage growth reduction varied between 42 and 100% in batch co-cultures, between 28 and 100% in semi-continuous co-cultures, and between 21 and 100% in isolated co-cultures. In addition, we examined the potential allelopathic effect of U. pertusa culture filtrate. The Ulva culture filtrate significantly (p<0.01) inhibited the growth of C. placoidea from 2 days after incubation until the end of the experiment, and it exhibited no inhibitory effect on the growth of the other microalgal species. This may suggest that the allelochemicals released from U. pertusa are rapidly degradable.The microalgae tested exhibited different (stimulatory, inhibitory or no) effects on the growth of U. pertusa. U. pertusa grew faster with H. akashiwo (+16%) and S. costatum (+9%), less with T. subcordiformis (−20%), N. closterium (−23%) and C. gracile (−30%), but was not significantly affected by I. galbana, A. tamarense and C. placoidea. The microalgae tested exhibited no clear allelopathic effects on U. pertusa.