改性粘土治理藻华对主要营养元素循环及藻毒素的影响

发布时间：2018-02-28 12:03

本文关键词： 有害藻华治理改性粘土营养元素毒素生态效应　出处：《中国科学院研究生院（海洋研究所）》2014年博士论文　论文类型：学位论文

【摘要】：随着人类活动增多、气候变化等因素影响，近年近岸有害藻华的暴发频率和规模不断增加，，其引起的海洋生态问题日益凸显。改性粘土治理有害藻华是国际上推荐的野外应急治理方法之一。本论文通过室内实验，开展改性粘土治理不同藻华生物的长期环境化学效应的研究，针对有害甲藻藻华、硅藻藻华自然消亡过程中营养盐循环特性及改性粘土絮凝后所引起水质营养环境的差异特征以及改性粘土治理有毒藻华过程中对水和沉积物环境因子、藻毒素的影响研究，结合分析大量粘土絮凝有害藻华机理、元素生物地球化学循环、粘土材料结构特性等研究文献，获得以下几方面的阶段性成果： (1)改性粘土治理方法能够高效絮凝去除高密度有害藻华生物P. micans、P.donghaiense、S. costatum、A. tamarense，由于硅藻细胞外壳含有大量硅元素，与粘土中铝元素易发生离子置换，外加硅藻细胞的自沉降特性，所以改性粘土对硅藻去除效率更为显著，改性粘土通过“互荫”效应、改变营养结构和胶体缓冲体系等方式影响有害藻华生物的微生境，显著影响其细胞代谢合成不同的荧光物质，单位藻细胞有机氮和磷短期内显著升高，改性粘土治理方法有效抑制了有害藻华生物二次增殖。 (2)自然消亡过程中藻源有机物在降解过程中会释放大量营养物质，这些营养物质可为二次藻华暴发提供物质基础，改性粘土治理方法在除藻的同时有效地改善了水质环境，水体中TN、TP大幅降低，且未出现二次释放。实验末期海洋原甲藻P. micans改性粘土絮凝后TP约去除39.28%~42.47%，TN约去除26.22%~29.93%；东海原甲藻P. donghaiense改性粘土絮凝后TP约去除51.39%，TN约去除17.24%；中肋骨条藻S. costatum改性粘土絮凝后TP约去除93.36%%~93.60%，TN约去除53.75%~71.95%；塔玛亚历山大藻A. tamarense改性粘土絮凝后TP约去除42.86%~56.30%，TN约去除20.72%~35.53%。 (3)改性粘土改变了水体中营养元素的浓度、形态比例以及元素循环过程，磷酸盐和硅酸盐以直接吸附影响为主，而溶解态无机氮以时间累加的间接效应为主，有效地降低了水体营养程度，由于不同营养元素的去除机理和速率有所不同（无机营养元素转化速率依次为v(NO3--N)v(DIP)v(NO2--N)v(NH4+-N)），造成营养结构发生改变，改性粘土促进了藻华生物对无机态营养物质的吸收，同时加快了颗粒态营养物质的沉降速率，水体中TDN/TDP比值显著增加（100），形成极度磷限制环境从而破坏了藻细胞二次增殖所需的适宜营养条件。 (4)改性土治理方法形成的藻土有机粘土复合体聚合富集沉降大量有机氮和有机磷物质进入沉积物表层，通过沉积物颗粒、改性粘土颗粒与上覆水环境的离子交换作用、金属有机物螯合作用、沉积物压实作用等机制促使营养物质在月尺度上无法快速解吸或释放，同时改性粘土具有一定的抗微生物活性特征，减缓了有机氮、磷的降解，在月尺度上无机营养盐浓度未发生改变，使得这部分有机物如化石埋赋一样保存于沉积物中；另一方面，粘土颗粒表面为某些有机物质的聚合反应提供反应位置和催化中心，改性粘土自身的表面富集和选择催化特性促使叶绿素a和藻毒素PSTs等活性有机物质转化加速，沉积物中高毒性GTX1和GTX4向较低毒性GTX2和dcGTX3转化，尤其是沉积物-海水环境中，pH值和氧化环境在PSTs降解转化过程中起重要作用，毒素由高毒性向低毒性甚至无毒物质转化速率显著加快。改性粘土治理方法形成的絮体与“海洋雪”具有一定的相似性，但絮体来源、组成、形成状态有所不同。由于改性粘土添加是人为突发过程，对于自然水体而言这一过程如海底火山喷发般能突然改变区域微生物活性和元素地球化学循环过程。所以，针对特定水体条件和藻种，在筛选改性粘土用量和去除时应深入研究生态效应信息，在大规模施行前需要进行长时间尺度生态效应研究以保证安全使用这一治理方法。尽管本课题组针对改性粘土治理方法野外应用积累了大量经验，但是我们依然建议应该对其造成的环境影响需要慎重评估。研究改性粘土治理有害藻华后期营养元素的生物地球化学规律，对于正确认识海洋中的有害藻华消亡及有害藻华治理的后期生态效应都有重要意义。
[Abstract]:With the increasing human activities, climate change and other factors, in recent years, the coastal harmful algal blooms outbreak frequency and increasing scale, marine ecological problems caused by the increasingly prominent. The modified clay treatment of harmful algal blooms is one of the internationally recommended field emergency treatment method. This paper through indoor experiments, research on long-term effects of environmental chemistry clay treatment of different algae organisms, the harmful dinoflagellate algae, differences in the characteristics of water quality and nutrition environment caused by modified clay flocculation nutrient cycling characteristics of diatom bloom in the process after the demise of the natural and modified clay treatment of toxic algal blooms in the process of water and sediment environmental factors, effects of microcystins combined with the analysis of a large amount of clay, the flocculation mechanism of harmful algal blooms, the biogeochemical cycling of elements, the study of clay material structure characteristic of literature, acquired the following form Fruit:
(1) modified clay treatment method can remove the high density of harmful algal bloom species P. micans, S. costatum, P.donghaiense, flocculation, A. tamarense, the diatom cells contain a large number of silicon shell elements, and the elements in the aluminum clay prone ion exchange, and the characteristics of diatom cell death, so the removal efficiency of modified clay on diatom more significantly, the modified clay by "shadow" effect, change the microhabitat of harmful algal blooms biological effects of nutrient structure and colloid buffer system etc., significantly affect the cell metabolism synthesis of different fluorescent materials, unit cell organic nitrogen and phosphorus increased significantly in the short term, the modified clay treatment method can effectively restrain the harmful two biological algae proliferation.
(2) algae source organic natural death process will release a large amount of nutrients during the degradation process, these nutrients can provide the material basis for the two time the outbreak of algal blooms, modified clay treatment method improves water environment effectively while removing algae in water, TN, TP significantly reduced, and did not appear two release. At the end of the experiment Prorocentrum P. micans modified clay flocculation after removal of 39.28%~42.47% TP about TN, about the removal of 26.22%~29.93%; dinoflagellate P. donghaiense modified clay flocculation TP after removal of about 51.39%, about 17.24% TN removal; Skeletonema costatum S. costatum modified clay flocculation TP after removal of about 93.36%%~93.60%, TN about the removal of 53.75%~71.95%; Alexander A. tamarense tajmar algae modified clay flocculation after removal of TP about 42.86%~56.30%, TN about the removal of 20.72%~35.53%.
(3) modified clay changed the concentration of nutrient elements in the water, the proportion of form and element cycle, mainly by direct adsorption effects of phosphate and silicate, and dissolved inorganic nitrogen in the indirect effect time accumulation, effectively reduce the water eutrophication degree, different from the removal mechanism and rate in different nutrient elements (inorganic nutrients conversion rate were V (NO3--N) V (DIP) V (NO2--N) V (NH4+-N)), the nutrition structure changed, modified clay can promote the absorption of algae biological inorganic nutrients, and accelerate the sedimentation rate of particulate nutrients in the water, the ratio of TDN/TDP significantly increase (100), a form of extreme environment to the destruction of phosphorus limited algae cell proliferation two times the optimal nutritional conditions.
(4) organic clay soil algae complex formation of modified soil treatment methods of polymerization enrichment of settlements of a large number of organic nitrogen and organic phosphorus substances into the surface sediments, the sediment particles, modified clay particles and ion exchange effect of overlying water environment, metal organic chelation, sediment compaction and other mechanisms that promote the nutrients in monthly scale not quick desorption or release of the modified clay has certain characteristics of anti microbial activity, slowing the degradation of organic nitrogen, phosphorus, in the month scale inorganic nutrient concentrations did not change, so this part of organic matter such as fossil buried sediments deposited in the same host; on the other hand, the clay particle surface the polymerization of organic materials to provide the location of the response and the catalytic center, modified clay's surface enrichment and selective catalytic properties to chlorophyll a and algal toxins such as PSTs activity of organic compounds The acceleration of the transformation of matter, the high toxicity of GTX1 and GTX4 in sediments from GTX2 to lower toxicity and dcGTX3 transformation, especially the sediment water environment, plays an important role in pH and oxidation environment transformation process in the degradation of PSTs, from high to low toxic poisonous toxins or non-toxic substance conversion rate significantly accelerated.
Floc formation of modified clay treatment method and the "marine snow" has a certain similarity, but the floc origin, composition, form different. Because the modified clay is added for emergency process, for the process of natural water such as a submarine volcano eruption can suddenly change regional geochemical and microbial activity cycle. Therefore, according to the specific conditions of water and algae, we should study the ecological effect of information in the screening of modified clay dosage and removal, before the implementation of the need for research in large scale ecological effect of long time using this method to ensure safety management. Although the research group for the modified clay treatment field accumulation a lot of experience, but we still suggest that environmental impact should be the need to carefully assess students. To study the modified clay treatment of harmful algal blooms late nutrition elements The geochemical law is of great significance to the correct understanding of the extinction of the harmful algal blooms in the ocean and the late ecological effects of harmful algal blooms.

【学位授予单位】：中国科学院研究生院（海洋研究所）
【学位级别】：博士
【学位授予年份】：2014
【分类号】：X55

【参考文献】