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滇池水华蓝藻群落演替及麻痹性贝毒素时空分布研究
Alternative TitleStudies on Bloom-forming Cyanobacteria Community Succession and Spatio-temporal Distribution of Paralytic Shellfish Poisons (PSPs) in Lake Dianchi
苏彦平
Subtype硕士
Thesis Advisor李敦海
2008-06-14
Degree Grantor中国科学院水生生物研究所
Place of Conferral水生生物研究所
Keyword蓝藻水华 群落演替 水华束丝藻 麻痹性贝毒素 时空分布
Abstract有毒蓝藻水华的防治是世界性环境难题。随着蓝藻水华暴发频率和强度的增加,已成为严重的环境问题之一。蓝藻水华最大的危害就是其代谢的蓝藻毒素,研究表明蓝藻毒素不仅造成水生态系统恶化,而且可能威胁到人类健康。蓝藻中束丝藻(Aphanizomenon) 等产生的PSPs毒素,属生物碱类神经毒素,其中STX对小鼠的半致死量仅为10 μg/kg,是蓝藻毒素中毒性最大的一种。近年来,我国一些富营养化水体中越来越频繁的出现水华束丝藻(Aphanizomenon flos-aquae)及其形成的水华,然而我国在淡水蓝藻水华产生的PSPs毒素方面的相关研究却较少。充分地认识和了解束丝藻水华的发生过程、产毒特性及其生态风险,对于更好地制定和实施控藻策略有重要指导意义。本文主要开展了束丝藻水华在富营养化水体滇池中的发生过程及束丝藻毒素在滇池的时空分布研究,同时初步研究了大理洱海、贵州阿哈湖和红枫湖束丝藻的产毒特性,主要内容包括: 1. 对富营养化水体滇池中束丝藻麻痹性贝毒素(PSPs)的时空分布情况进行了为期一年的研究。结果发现,滇池全湖水体中PSPs从三月份开始逐渐升高,在四月中旬达到最高值20.65 ng/mg.DW,而后略有降低并持续到5月份并仍保持较高水平(15.29 ng/mg.DW),而后迅速下降,至7月份后低于检测限。单点最高值出现在四月初,达到56.6 ng/mg.DW。在束丝藻水华发生的初期PSPs最早出现的异构体是GTX4;在束丝藻水华生物量快速增长期间,PSPs主要由GTX4及STX组成,而后GTX4被GTX1所取代。GTX5也是较早出现的一种毒素异构体,但其含量并不高,同时在束丝藻暴发期间存在少量dcGTX2,3。总体来说,滇池发生的束丝藻水华中检测到的GTXs含量低于STXs含量。在水华暴发过程中PSPs种类组成也发生着变化,可能与束丝藻自身的代谢需要及水体环境因子变化有关。 2. 研究了滇池中水华蓝藻的群落演替以及水体理化因子的变化情况。研究发现,滇池的蓝藻水华主要为微囊藻水华和束丝藻水华随时间交替发生。初步分析结果表明,束丝藻水华暴发时的水温较低,范围为15-19℃;全湖氮/磷比总体较低,氮/磷比全年平均值为15.2,大部分月份低于29,只有在5月份至6月份忽然升高,此时全湖氮磷比均高于40。在束丝藻暴发时氮为相对限制因子,在微囊藻水华暴发时磷为相对限制因子。这可能是因为束丝藻具有自身固氮的特性,在低氮磷比时比微囊藻能更有效的利用氮源。而在束丝藻水华消退时氮磷比迅速上升,可能是由于束丝藻细胞在死亡时释放了大量细胞内固定的氮。 3. 对几个高原淡水湖泊的束丝藻水华及PSPs进行了初步研究。经小鼠生物法和高效液相色谱法检测,发现贵州阿哈湖束丝藻具有较强的毒性,贵州红枫湖、大理洱海束丝藻毒性较小。PSPs含量和种类上,分别为阿哈湖:23.62 ng/mg.DW,主要为STX类;红枫湖:4.10 ng/mg.DW,主要为neoSTX:;大理:只检出dcGTX3,2.63 ng/mg.DW。这一研究结果进一步为水体安全性和人类饮用水安全保障提出了警示。 本研究可为我国淡水湖泊麻痹性贝毒素的风险评估和污染控制提供重要数据支持和依据,更进一步的研究工作应更关注PSPs毒素的生态毒理学及束丝藻水华的控制技术。
Other AbstractToxic cyanobacterial bloom in freshwater lakes and ponds has been reported frequently due to the increasing eutrophication, and it became a worldwide serious environmental problem. Cyanotoxins, one of the disasters originated from bloom-forming cyanobacteria may cause the major health concerns to humans, as well as to the wildlife. Aphanizomenon flos-aquae, one of the dominant bloom-forming species of cyanobacteria in freshwaters, can synthesize toxins belonging to alkaloid called the paralytic shellfish poisons (PSPs), of them the LD50 of STX is only 10μg/kg to mouse. In recent years, Aphanizomenon blooms were frequently observed from freshwater bodies in China. However, there was little information on the distribution of PSPs toxins in freshwater lakes. In this paper, the spatio-temporal distribution of PSPs in Lake Dianchi and other lakes such as Aha, Hongfeng and Erhai, as well as the bloom-forming cyanobacteia community succession were studied. The main results are as follows: 1. The spatio-temporal distribution of PSPs from Aphanizomenon in Lake Dianchi was investigated for one year. The PSPs toxin in Dianchi began to appear in March, and then increased gradually to the highest level (20.65 ng/mgDW) in mid April. After a short term of decreasing, the content of PSP toxins keeping a steady level (15.29 ng/mg.DW) till May. And then PSPs content in cyanobacterial biomass drop quickly to the detecting limit in July. Moreover, toxin analogues varied greatly during the water bloom occurring process. In the early stage of Aphanizomenon bloom, Gonyautoxin-4 (GTX4) was detected first, and in the fast growing stage of Aphanizomenon bloom the two main analogues were saxitoxins (STX) and Gonyautoxin-4 (GTX4), then GTX4 was replaced by GTX1. GTX5 also appeared early, but the content was very low. And a few dcGTX2,3 was also detected during the blooming process. In general, the total content of STXs was much higher than GTXs in Lake Dianchi. 2. The bloom-froming cyanobacteria community succession and the physical and chemical parameters of water in Lake Dianchi were investigated from Dec.2006 to Nov.2007. Results showed that the dominant genera of cyanobacterial bloom were Microcystis and Aphanizomenon. The temperatures (15-19℃) for Aphanizomenon bloom occurring were lower than those (20-23℃) for Microcystis bloom. N/P ratios in Lake Diachi were not very high, with an average value of 15.2 for one year. For most months it was lower than 29, only raised in May and June and generally higher than 40. The ratio of N/P was low when Aphanizomenon bloom occurred, it domonstrated that Aphanizomenon was more competitive than Microcystis when TN was the limiting factor. 3. The toxicity of Aphanizomenon blooms from lakes Aha, Hongfeng and Erhai was also investigated. Standard mouse bioassay showed the Aphanizomenon blooms from lakes Aha and Hongfeng were toxic, while the toxicity of the Aphanizomenon bloom from Erhai is very low. The Oshima’ method for PSPs analysis by HPLC revealed Aphanizomenon blooms from these lakes produce PSPs toxins. The contents of PSPs in lakes Aha, Hongfeng and Erhai were 23.62 ng/mgDW, 4.10 ng/mgDW,2.63 ng/mg?DW respectively, with respective main toxins were STX, neoSTX and dcGTX3. For reducing contamination and assessing the health risk caused by PSPs, the current study is of crucial importance, and further researches concerning the ecotoxicology of PSPs and control methods for Aphanizomenon bloom are necessary.
Pages105
Language中文
Document Type学位论文
Identifierhttp://ir.ihb.ac.cn/handle/342005/12338
Collection学位论文
Recommended Citation
GB/T 7714
苏彦平. 滇池水华蓝藻群落演替及麻痹性贝毒素时空分布研究[D]. 水生生物研究所. 中国科学院水生生物研究所,2008.
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