【作者】 高咏卉；

【导师】 俞志明；

【作者基本信息】 中国科学院研究生院（海洋研究所） ， 环境科学， 2006， 硕士

【摘要】 本文以室内实验为基础,研究了改性粘土治理有害赤潮的方法对生态环境的影响。研究结果表明:有机和无机改性粘土对溶解氧(DO)、化学耗氧量(COD)、pH等主要水质因子均有改善作用;对营养盐,尤其是磷酸盐有一定的吸附作用,在外加磷酸盐为0-0.3μmol/ml范围内,吸附量随水体中磷酸盐浓度的增加而增大,有机改性粘土对海水中磷酸盐的吸附能力为:有机改性粘土Ⅰ>有机改性粘土Ⅱ>有机改性粘土Ⅲ。通过有机改性粘土对磷酸盐的吸附-再释放情况,进一步探讨了其磷酸盐的释放对赤潮异弯藻(Heterosigma akashiwo)、东海原甲藻(Prorocentrum donghaiense)等赤潮生物生长的影响。实验结果显示,经过有机改性的粘土有利于提高其对磷酸盐的吸附能力,降低对磷酸盐的解吸率,利用有机改性粘土治理赤潮可以缓解海水富营养化程度,即使被吸附的部分磷酸盐能缓慢释放,但仍不足以维持赤潮生物的正常生长。无机改性粘土对磷酸盐和硝酸盐与有机改性粘土有相似的吸附性能。其添加剂PAC的重金属含量符合沉积物排放要求,不会对环境造成压力。其次,以太平洋牡蛎(Crassostrea gigas)幼贝为对象,研究了有机改性粘土Ⅱ和无机改性粘土在对海洋底栖生物的影响。急性毒性试验中二者对牡蛎幼贝的半致死浓度(LC50)分别为4.62 g/L和2.67 g/L,均远远大于改性粘土去除赤潮藻的浓度。在能够有效去除赤潮微藻的粘土浓度条件下,经慢性毒性试验发现改性粘土对牡蛎幼贝成活率、生长和摄食略有降低,但无明显影响,在牡蛎幼贝鳃组织和消化道组织的超微结构中未发现机械损伤。最后,研究了改性粘土在对去除有毒赤潮藻过程中对底栖生物的影响。以能产生麻痹性贝毒(PSP)的塔玛亚历山大藻(A. tamarense,ATHK)为例,研究了PSP在水体中和粘土沉积层中的分布,发现改性粘土去除塔玛亚历山大藻能有效降低水体中藻细胞浓度及其所携带的PSP毒素。由于藻细胞破裂,虽然沉积层中藻细胞体内部分PSP毒素溢更多还原

【Abstract】 The primary objective of this study was to determine the environmental influences of clayflocculation in red tide blooms through laboratory test. The result as follows: When modifiedclay to control algae bloom, those water quality parameters were controlled or smoothed, suchas Dissolved Oxygen (DO), Chemical Oxygen Demand (COD) and pH. Moreover those clayscould absorp the eutrophic salt, especially phosphate. When phosphorus concentration rangedfrom 0.1μmol/mL to 0.3 μmol/mL, the phosphate adsorption amounts increased on organicmodified clays. The phosphate adsorption ability of different organic clays is: modifiedclayⅠ> modified clayⅡ> modified clayⅢ> unmodified clay. However, there is no obviousremoval ability of nitrate. To study the absorption-desorption effects on ecology, wesimulated the phosphate desorption and the consequent effect to the growth of Heterosigmaakashiwo and Prorocentrum donghaiense., the result show that d modified clay could holdmore phosphate on itself, which will be helpful to mitigate eutrophication. Moreover,phosphate desorption in sea water could not afford phytoplankton growth. Inorganic modifiedclay is similar to the organic clays of the ability on nitrates. Mitigation or control the red tid byorganic/ inorganic modified clays could enchance the water quality parameters.Then modified clays were tested for the potential environmental impact on benthicorganism. Laboratory experiments were conducted to investigate the survival and physiologicalchanges of infant oyster (Crassostrea gigas). LC50 (96h ) of organic and inorganic modifiedclay are 4.62 g/L和2.67g/L,which is higher than clay concentration in practical red tidmanagment. The percentage survivals of oysters,Filtering rate and growth in modified clays atpractical concentration are almost equal to those in control during acute and chronic toxicity. in56 days erposure in 0.10 g /L organic or inorganic modified clays. Results of TransmissionElectron microscopy showed that both clays have no physical hurt to the gill and digestivegland of infant oyster after chronic test. Clay modification was not acutely or chronically toxicin most cases.Finally, because paralytic Shellfish Poisoning (PSP) is the most serious and widespreadshellfish toxicity, this study was undertaken to assess the ability of phosphatic clay to removethe toxic dinoflagellate, A. tamarense, which produce PSP toxins. Results showed that theaddition of aqueous slurry can reduce A. tamarense and PSP from seawater. In clay sedimentwhen upon rupture or lysing of the cells, the toxins can be released into the water column asextracelluar toxin, however, it has little effect on oyster compared with control for toxinsdiluted in seawater after cell break, and oyster get lease toxicity form gulf or rupture the PSP inseawater than algae directly. Moreover, laboratory tests simulated the toxicity to C. gigas byclay flocculation of the toxic dinoflagellate, A. tamarense (ATHK), Heterosigma akashiwo andProrocentrum donghaiense. The result suggests that clay flocculation of algae cell will increasethe survival rate of infant oyster compared with untreated blooms. Therefore, modified clayshave prospective future in control harmful algal blooms as emergency methods.更多还原