赤潮生消过程中赤潮藻类稳定同位素组成变化

发布时间：2018-04-28 14:57

本文选题：赤潮藻 + 营养盐　；参考：《大连海事大学》2015年硕士论文

【摘要】：为了探索赤潮发生机理及监测预防的新思路和方法,本研究在实验室条件下,以塔玛亚历山大藻(Alexandrium tamareme)、裸甲藻(Gymnodinium aerucyinosum Stein)、中肋骨条藻(Skeletonema costatum)和小新月菱形藻(Nitzschia closterium)为实验材料,在以Conway培养基培养下,测定这四种赤潮藻(分属甲藻和硅藻)模拟赤潮生消过程中重要监测指标(细胞数量、营养盐浓度)的变化,探讨不同生长阶段微藻的碳、氮稳定同位素特征值与之相关变化规律。培养过程分为单种培养和两种不同组合的混合培养,在此基础上对比分析了微藻单种培养与种群竞争培养过程中细胞数量、营养盐浓度以及碳、氮稳定同位素的组成变化规律的异同。理论依据是赤潮过程伴随营养状况如碳源及氮源等的变化,赤潮藻类对生源元素的选择性吸收将导致碳、氮稳定同位素的动力学分馏,即当营养元素充足时,赤潮藻会优先选择吸收能级较低的12C和14N,营养不足时则被迫吸收较重的13C和15N。实验结果表明：藻种生长过程可明显分为四个阶段：适应期、对数生长期、稳定生长期及衰亡期；氮、磷营养盐浓度随培养时间呈下降趋势,与细胞数量的变化有很好的相关性,微藻对于氮源的吸收利用取决于微藻的种类、外部环境中不同氮源的相对浓度是否达到微藻吸收的最适浓度,相对于氮源来说,微藻对磷源的需求相对较少,四种实验藻种均对磷酸盐有储存能力；甲藻在增殖过程中几乎不消耗硅酸盐,而其却是硅藻生长分裂必不可少的元素；在一次完整的赤潮发生过程中,碳稳定同位素组成(δ13C值)随时间显示出减小趋势或基本维持稳定,而氮稳定同位素组成(6’5N值)值则显示增大趋势；微藻竞争培养中615N的变化趋势没有改变,与单种培养相比有更正的值,变化范围更广,并与细胞数量、氮源的变化有很好的相关性,δ13C值的变化显示碳元素吸收过程中没有明显分馏现象,但与单种相比有更正的值。因此,赤潮藻的碳、氮稳定同位素组成可以为赤潮监测提供了可能的新指标和新方法,为初步探索赤潮机理提供一定数据基础。
[Abstract]:In order to explore the mechanism of red tide and its monitoring and prevention, we used Alexandrium tamaremeg, Gymnodinium aerucyinosum Steinnum, Skeletonema costatum and Nitzschia closteriumas as experimental materials under laboratory conditions. In Conway culture medium, the changes of the important monitoring indexes (cell number, nutrient concentration) of the four species of red tide algae (belonging to Proroidophyta and diatom) during simulated red tide generation and elimination were determined, and the carbon of microalgae in different growth stages was studied. The characteristic values of nitrogen stable isotopes are correlated with them. The culturing process was divided into single culture and mixed culture of two different combinations. On the basis of this, the cell number, nutrient concentration and carbon in the process of single microalgae culture and population competition culture were compared and analyzed. Differences and similarities of the composition of nitrogen stable isotopes. The theoretical basis is that the process of red tide is accompanied by changes of nutrition such as carbon source and nitrogen source. The selective absorption of biological elements by red tide algae will lead to the kinetic fractionation of stable isotopes of carbon and nitrogen, that is, when the nutrient elements are sufficient, Red tide algae preferred 12C and 14N with lower absorption energy levels, and were forced to absorb more 13C and 15N when they were undernourished. The results show that the growth process of algae can be obviously divided into four stages: adaptation period, logarithmic growth period, stable growth period and decaying stage, and the concentration of nitrogen and phosphorus decreases with culture time. The absorption and utilization of nitrogen sources by microalgae depends on the species of microalgae, and whether the relative concentrations of different nitrogen sources in external environment reach the optimum concentration of microalgae, as opposed to nitrogen sources, There is relatively little demand for phosphorus sources in microalgae, and the four experimental algae species have the ability to store phosphate, while Pyrophyta almost does not consume silicate in the process of proliferation, but it is an essential element for the growth and division of diatoms. During a complete red tide, the carbon stable isotopic composition (未 13 C) showed a decreasing trend or remained stable with time, while the nitrogen stable isotope composition showed an increasing trend. The change trend of 615N in the competition culture of microalgae was not changed. Compared with the single culture, the change range of 615N was wider than that of single culture, and the change range was wider than that of single culture. The change of nitrogen source has a good correlation. The change of 未 13C value shows that there is no obvious fractionation phenomenon in carbon absorption process, but there is a corrected value compared with the single one. Therefore, the stable isotopic composition of carbon and nitrogen of red tide algae can provide a new index and a new method for red tide monitoring, and provide a certain data basis for preliminary exploration of red tide mechanism.
【学位授予单位】：大连海事大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X55

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