氨、亚硝酸盐及其与藻毒素对两种水蚤生活史特征的影响

【作者】 向馥徽；

【导师】 杨州；

【作者基本信息】 南京师范大学 ， 水生生物学， 2011， 硕士

【摘要】 蓝藻水华集聚后腐烂分解会释放细胞内微囊藻毒素并产生衍生污染物亚硝酸盐、氨等,导致局部水域水质的严重恶化。为了确定微囊藻毒素、亚硝酸盐、氨对浮游动物的危害,本实验选取太湖常见种D. similoides, D. obtusa为受试生物,通过微囊藻毒素、亚硝酸盐、氨三种毒物对两种蚤的急性和慢性暴露实验,得出以下结果：1.氨和亚硝酸盐对D. similoides不同龄期(0.5、1、3、5、7 d)的急性实验亚硝酸盐对D. similoides各个龄期的24 h和48 h LC50都随着龄期的增加而增大,除了5日龄和7日龄之间不存在显著差异(P>0.05)外,其它各龄期之间彼此都存在显著性差异(P<0.05)；用修正的高斯模型拟合D. similoides不同龄期LC50,可知亚硝酸盐对D. similoides的24 h和48 h LC50的最大值分别为156.99和63.09mg/L,而达到最大值所对应的日龄分别为6.25和5.74天。NH3-N对不同龄期D. similoides的24 h和48 h LC50中,当到达3日龄后,LC50不再随日龄的增大而增大,5日龄的24 h和48 h LC50与3日龄的不存在显著性差异。用修正的高斯模型拟合NH3-N对D. similoides不同龄期的LC50,可知NH3-N对D. similoides 24 h和48 h LC50的最大值分别为1.74和1.33 mg/L,而达到最大值所对应的日龄分别为3.98和4.03天。用修正的高斯模型可以很好的拟合D. similoides不同龄期的LC50的变化趋势,获得达到最大LC50时所对应的日龄,这个模型可能也适用于其它种类Daphnia在急性实验中不同龄期LC50的变化趋势。2.氨和亚硝酸盐对D. similoides和D. obtusa的慢性毒理效应在氨和亚硝酸盐对D. similoides和D. obtusa的21天慢性实验中,考察了指标首次怀卵／繁殖时间、首次怀卵／繁殖体长、蜕皮次数、繁殖次数、平均每窝繁殖量、平均母体繁殖量、平均存活天数,运用四参数逻辑斯蒂方程对各指标进行模拟,可获得相应指标的EC50,对比各指标参数的最低可见效应浓度(LOEC)、最低可见无效应浓度(NOEC)及EC50,可知各参数的敏感性次序：氨对D. similoides各参数的敏感性：首次怀卵时间=首次繁殖时间=平均每窝繁殖量>平均母体繁殖量>平均繁殖窝数>平均存活天数>平均蜕皮次数。氨对D. obtusa各参数的敏感性：平均母体繁殖量>平均每窝繁殖量>首次繁殖时间=首次怀卵体长=首次生殖体长>平均繁殖窝数>平均存活天数>平均蜕皮次数。在氨对D. similoides和D. obtusa各指标的作用中,氨对D. similoides的首次怀卵／繁殖时间、D. obtusa的首次繁殖时间随着浓度的增大具有显著延长的效果,对D. similoides的首次怀卵／繁殖体长没有显著作用,但对D. obtusa的首次怀卵／繁殖体长在低浓度(0.01076,0.0538 mg/L)时具有刺激作用,体长明显长于其它各浓度组的体长。氨对D. similoides和D. obtusa的平均每窝繁殖量和平均母体繁殖量在低浓度时也表现出刺激作用。通过NH3-N对D. similoides和D. obtusa各参数的敏感性次序,知平均每窝繁殖量和平均母体繁殖量较其它指标要敏感,两指标的NOEC和LOEC分别为0.0538 mg/L和0.1076 mg/L,可知两种蚤对低浓度NH3-N的敏感性相同,比较两种蚤的EC50,D. similoides平均每窝繁殖量对NH3-N的EC50为0.58mg/L, D. obtusa平均母体繁殖量对NH3-N的EC50为0.27 mg/L,可知D. obtusa较D. siniloides对NH3-N要敏感。亚硝酸盐对D. similoides各参数的敏感性：平均母体繁殖量>平均每窝繁殖量>平均繁殖窝数>平均蜕皮次数>平均存活天数。亚硝酸盐对D. obtusa各参数的敏感性：首次生殖体长=平均母体繁殖量>平均每窝繁殖量>首次怀卵时间=首次繁殖时间>平均蜕皮次数>平均繁殖窝数>平均存活天数。在亚硝酸盐对D. similoides和D. obtusa各指标的作用中,亚硝酸盐对D.similoides的首次怀卵／繁殖时间、首次怀卵／繁殖体长以及对D. obtusa的首次怀卵／繁殖时间、首次怀卵体长都没有影响。通过各指标的敏感性次序知平均每窝繁殖量和平均母体繁殖量较其它指标要敏感。比较两种蚤平均母体繁殖量的LOEC和EC50, D. similoides分别为1 mg/L和1.56 mg/L, D. obtusa分别为0.1 mg/L和1.59mg/L,可知D. obtusa较D. similoides对低浓度的N02-N要敏感,但达到半数效应时两者的浓度几乎一样。3亚硝酸盐联合藻毒素对D. obtusa的复合实验亚硝酸盐联合藻毒素对D. obtusa的15天复合实验中,在参数首次怀卵时间(P=0.020)和首次繁殖时间(P=0.021)上都存在显著的交互作用,首次怀卵/繁殖时间不仅依赖于亚硝酸盐浓度,还依赖于藻毒素浓度,在亚硝酸盐和藻毒素的交互作用中,藻毒素表现出能一定程度上缓解亚硝酸盐对D. obtusa怀卵和繁殖的推迟作用。在其它参数首次怀卵/繁殖体长、平均每窝繁殖量、平均母体繁殖量、平均蜕皮次数及平均繁殖次数上,亚硝酸盐和藻毒素在联合毒性上表现为独立作用,因藻毒素对各参数没有显著性影响,可完全看成是亚硝酸盐对以上各参数的损害。4氨联合藻毒素对D. similoides的复合及修复实验在氨联合藻毒素对D. similoides的复合实验中,检测了首次怀卵/繁殖体长、首次怀卵/繁殖时间、平均每窝繁殖量、平均母体繁殖量、平均繁殖次数、平均蜕皮次数,在参数首次怀卵时间上氨和藻毒素存在交互作用(P=0.026),在作用过程中藻毒素表现出能一定程度上缓解氨对D. similoides怀卵的推迟作用。在参数首次繁殖时间上氨和藻毒素没有表现出显著的交互作用,但氨对D. similoides首次繁殖时间的影响受藻毒素的影响,而藻毒素对D. similoides首次繁殖时间的影响要依赖于氨浓度。对平均每窝繁殖量,氨和藻毒素没有表现出显著的交互作用,氨对D.similoides平均每窝繁殖量的影响不依赖于藻毒素浓度,但藻毒素对此指标的影响要依赖于氨浓度。氨和藻毒素对参数平均母体繁殖量表现为独立作用,二者对此参数都有一定的影响。对指标平均繁殖次数,氨和藻毒素表现为独立作用,因藻毒素没有显著性影响,可完全看成是氨对此参数的损害。对参数首次怀卵/繁殖体长、平均蜕皮次数,氨和藻毒素没有表现出毒害作用。在修复实验中,检测了参数平均蜕皮次数、平均繁殖窝数、平均每窝繁殖量、平均母体繁殖量。平均蜕皮次数和平均繁殖窝数在修复实验中各组间没有显著性差异,说明氨和藻毒素确实对两参数不存在影响。对平均每窝繁殖量和平均母体繁殖量,高浓度处理组在修复实验中繁殖量大于低浓度处理组,表现出在慢性实验中抑制因子越大,在修复实验中繁殖指标恢复的更迅猛,称为“繁殖补偿”理论,或者理解为两指标很敏感,一旦外界环境中没有了抑制因子,其恢复的也比较快。更多还原

【Abstract】 Blue-green algae will release intracellular microcystin and produce secondary pollutants such as nitrite and ammonia during the degradation after cyanobacterial blooms accumulated in local region, and thus cause serious water quality problems. In order to evaluate which materials are harmful to zooplankton among nitrite、ammonia and microcystin, D. similoides and D.obtusa, the common species of zooplankton in Lake Taihu, were used in the experiments. From the acute and chronic exposure experiments of nitrite、ammonia and microcystin to D. similoides and D. obtusa,we can get the following conclusions:1 The acute toxicity of ammonia and nitrite to D. similoides at different developmental stages (0.5、1、3、5、7 d)The 24-h and 48-h LC50 of nitrite to D. similoides at different developmental stages increase as the instar grows, the other instar all have significant difference (P< 0.05) except 5 and 7 days;a modified Gaussian model was used to describe the trends of changes in LC50s at different stages in D. similoides, we can get the maximum LC50 of nitrite at 24h and 48h which were 156.99 and 63.09 mg.L-1 respectively;the age that LC50s of nitrite at 24h and 48h reached the maximum values were 6.25 and 5.74 days,respectively.The 24-h and 48-h LC50 of ammonia to D. similoides at different developmental stages will not vary with instar increasing when it was over 3 days old, and there were no significant difference between 5days and 3days on the 24-h and 48-h LC50. a modified Gaussian model was used to describe the trends of changes in LC50s at different stages in D. similoides, we can get the maximum LC50 of ammonia at 24 h and 48 h which were 1.74 and 1.33 mg L-1,respectively; the age that LC50s of ammonia at 24 and 48 h reached the maximum values were 3.98 and 4.03 days,respectively.Using the modified Gaussian model, we can describe the trends of changes in LC50s of nitrite and ammonia to D. similoides at different developmental stages.we can gain an insight into the maximum LC50 and the age that has the maximum LC50 and predict LC50s at any specific ages. We suggest that such a model might be used to describe the trend in acute toxicity of some other zooplankton species at different stages.2 The chronic toxicity effect of ammonia and nitrite to D. similoides and D. obtusaDuring the 21 days chronic experiment of ammonia and nitrite to D. similoides and D. obtusa, we evaluate the following parameters:time to first eggs/clutches、body length at first eggs/clutches、number of moults、number of clutches、mean number of offspring per clutch、mean number of offspring per female、mean survival days. And four-parameter logistic model was chosen to fit the indexes’data, we can get the indexes’EC50,respectively, contrast the LOEC、NOEC and EC50 among the indexes, The order of sensitivity of all indexes was as following:Ammonia to D. similoides:time to first eggs/clutches=mean number of total offspring per clutch> mean number of total offspring per female> mean number clutches> mean survival days> mean number moults.Ammonia to D. obtusa:mean number of total offspring per female>mean number of total offspring per clutch>time to first clutches=body length at first eggs/clutches>mean number clutches> mean survival days> mean number moults.Of the all indexes of ammonia to D. similoides and D. obtusa, the time to first eggs/clutches of D. similoides and time to first clutches of D. obtusa was significantly delayed with ammonia increasing, ammonia to D. similoides body length at first eggs/clutch have no significantly effect, but to D. obtusa’ body length at first eggs/clutch have a stimulation at low concentration (0.01076,0.0538 mg/L), the body length is longer than other concentrations’. To mean number of offspring per clutch and mean number of total offspring per female stimulation effect also appear at low concentration. From the order of sensitivityof all indexes,we know mean number of offspring per clutch and mean number of total offspring per female was the most sensitive indexes in both D. similoides and D. obtusa,the two index’s NOEC and LOEC is 0.0538 mg/L and 0.1076mg/L respectively,it suggests both Daphnia has the same sensitivity to low ammonia concentration,then assessing the EC50,mean number of offspring per brood of D. similoides was 0.58 mg/L,mean number of total offspring per female of D. obtusa was 0.27 mg/L, it suggests D. obtusa was more sensitive than D. similoides.Nitrite to D. similoides:mean number of total offspring per female> mean number of total offspring per clutch>mean number clutches>mean number moults>mean survival days.Nitrite to D. obtusa:body length at first clutches= mean number of total offspring per female> mean number of total offspring per clutch>time to first eggs/clutches>mean number moults>mean number clutches>mean survival days.During the nitrite to D. similoides and D. obtusa’ experiment,the time to first eggs/clutches、body length at first eggs/clutches of D. similoides and time to first eggs/clutches、body length at first eggs of D. obtusa was not effected.through the order of sensitivity of all indexes, mean number of total offspring per female and mean number of total offspring per clutch was the most sensitive.Contrast the LOEC and EC50 of mean number of total offspring per female among the two species, D. similoides was 1 mg/L and 1.56 mg/L respectively, D. obtusa was 0.1 mg/L and 1.59 mg/L respectively,it suggests D. obtusa was more sensitive than D. similoides to low nitrite concentration, but the value at which they reach the EC50 concentration was almost the same3 Combined effects of nitrite and microcystin to D. obtusaDuring the 15days combined experiment,the parameters time to first eggs(P=0.020)and time to first clutches (P=0.021) all have significant interaction, the influence of time to first eggs/clutches not only depends on nitrite concentration,but also depends on microcystin concentration,during the combined effects of nitrite and microcystin, microcystin can reduce the harmful effects caused by nitrite on delaying time to first eggs/clutches. On the remaining parameters:body length at eggs/clutches、mean number of offspring per clutch, mean number of total offspring per female, mean number moultes,mean number clutches, nitrite and microcystin represent single effect, because microcystin didn’t exert significant influence on the parameters, we think the harmful effects was caused by nitrite.4 Combined effects of ammonia and microcystin to D. similoides and recovery experimentDuring the combined effects of ammonia and microcystin to D. similoides,we evaluate the parameters as following:time to first eggs/clutches, body length at first eggs/clutches, mean number of offspring per brood, mean number of total offspring per female, mean number clutches, mean number moultes. On the time to first eggs ammonia and microcystin represent interaction (P=0.026) and microcystin can reduce ammonia to delay time to first eggs. On the time to first clutches ammonia and microcystin don’t represent significant interaction effect but both influence the parameters depending on each other. On the mean number of offspring per clutch, ammonia and microcystin don’t represent significant interaction effect, ammonia can influence the parameter itself, but microcystin influence it depending on ammonia. On the mean number of offspring per female, ammonia and microcystin represent independently, both influence it respectively. On the mean number clutches, ammonia and microcystin represent independently,but microcystin don’t represent significant influence, we think the all harm was affected by nitrite. On the remaining parameters, ammonia and microcystin didn’t represent any harmful effects.In the recovery experiment, we evaluate mean number moultes,mean number clutches, mean number of offspring per clutch, mean number of offspring per female.there was no significant difference between different concentrations on mean number moultes and mean number clutches in recovery,from this,we could conclude that ammonia and microcystin didnt have influence on the two parameters.as for the remaining two parameters, the offspring of high concentration treatments is higher than that of low concentration treatments in recovery experiment, it showed that individuals exposed to higher concentrations in chronic experiment had more fast recovery speed on reproduction index in recovery experiment,which is called’catch-up reproduction’theory. Maybe these two parameters are very sensitive, they will recovery rapidly when the suppression disappeared.更多还原