东海原甲藻和米氏凯伦藻种间竞争对海水温度变化的响应机制

发布时间：2018-03-27 07:11

本文选题：东海原甲藻　切入点：米氏凯伦藻　出处：《华东师范大学》2014年博士论文

【摘要】：已有的研究表明,全球气候变暖,海水温度上升,对海洋浮游植物种群的演变有重要影响。东海近岸海域中肋骨条藻、东海原甲藻和米氏凯伦藻是最近几年东海赤潮高发区主要赤潮生物。硅藻和甲藻赤潮演替经常交替进行(硅藻-甲藻-硅藻),营养盐水平的变化主导着硅藻与甲藻之间的演替,但是甲藻之间更替时营养盐几乎处于同样的水平,其他因素(温度、光照和盐度等)很有可能在东海原甲藻赤潮和米氏凯伦藻赤潮演替时起了决定性的作用。本文根据甲藻赤潮发生季节海水温度不断上升的情况以及海水中磷浓度较低的事实,研究不同温度(16-28℃,甲藻赤潮能够发生的主要温度区间)和营养盐水平对东海原甲藻和米氏凯伦藻生长、光合特性以及相关基因表达的影响；探讨正常营养盐水平和在低磷情况下不同温度对东海原甲藻和米氏凯伦藻种间竞争的影响以及东海原甲藻和米氏凯伦藻间化感作用；通过统计分析历年海水表温数据与甲藻赤潮爆发之间的相关性,预估全球气候变化情景下(变暖和变冷)的甲藻赤潮爆发趋势。主要研究结果如下： (1)模拟季节变化中海水温度升高的情景,研究不同温度培养对东海原甲藻和米氏凯伦藻生长、光合作用以及Rubisco基因表达的影响,结果表明东海原甲藻和米氏凯伦藻的最适生长温度分别为20和24℃,米氏凯伦藻生长速率大于东海原甲藻；东海原甲藻和米氏凯伦藻的最大光合作用分别出现在24和28℃,低温培养(16℃)显著降低对米氏凯伦藻光合作用,东海原甲藻的光合作用能力大于米氏凯伦藻；其中东海原甲藻和米氏凯伦藻的Rubisco基因最适表达温度分别为20和24℃。 (2)通过模拟甲藻赤潮发生季节海水中磷浓度较低的情景,研究不同营养盐水平对两种藻类生长的影响,培养中期(第12天)再次添加营养盐(f/2培养基)比一次性添加营养盐相比在实验后期可以显著提高两种藻类的细胞浓度,同步测定硝酸盐和磷酸盐浓度发现,两种不同营养盐水平培养下,东海原甲藻对硝酸盐吸收利用率均不高,对磷酸盐吸收利用率则较高,米氏凯伦藻对硝酸盐和磷酸盐的吸收利用率均非常高。在低磷情况下,东海原甲藻和米氏凯伦藻的生长均受到明显的抑制。 (3)在单培养实验的基础上,模拟东海区甲藻赤潮发生双赤潮的情景,研究正常营养盐水平和低磷条件下不同温度对东海原甲藻和米氏凯伦藻的种间竞争影响。结果显示,在正常营养盐情况下东海原甲藻在低温下(16-20℃)和起始细胞浓度比占优时与米氏凯伦藻的竞争中具有较大的优势,米氏凯伦藻在高温下(24-28℃)和高起始细胞浓度下(0.8×104cells ml-1)与东海原甲藻的竞争中具有绝对的优势。在低磷条件下,东海原甲藻和米氏凯伦藻生长规律呈现出先上升而后有所下降最后或上升或被抑制下降状态,在16℃培养条件下,在不同细胞起始浓度下东海原甲藻与米氏凯伦藻的竞争中有一定优势。米氏凯伦藻在高温下(24-28℃)与东海原甲藻的竞争中具有绝对的优势。因此,低磷条件增加了米氏凯伦藻对东海原甲藻的竞争优势。 (4)通过研究不同温度对两种甲藻化感作用影响时发现,米氏凯伦藻过滤液对东海原甲藻的生长产生很大抑制作用,其中与培养温度和东海原甲藻起始细胞浓度关系密切,即培养温度越低抑制越明显,同时东海原甲藻起始细胞浓度越高抑制作用越弱,米氏凯伦藻过滤液中化感物质对热比较敏感；东海原甲藻过滤对米氏凯伦藻的生长也有一定的抑制作用,但是东海原甲藻过滤液对热不敏感,米氏凯伦藻的生长抑制程度与米氏凯伦藻对温度的适应性有一定的关联,即在最适生长温度下米氏凯伦藻受东海原甲藻过滤液影响最小,另外,起始细胞浓度对结果也会产生一定的影响,低温低起始浓度(16℃,0.35×104cells ml-1)反而对米氏凯伦藻生长具有促进作用,但其机理尚不清楚。 (5)根据对2001年至2010年间东海原甲藻和米氏凯伦藻赤潮爆发时海水表面温度变化统计分析显示,东海原甲藻赤潮爆发时海水表面温度平均为20.30℃,属于偏低温爆发的赤潮；米氏凯伦藻赤潮爆发时海水表面温度平均为23.42℃,属于偏高温爆发的赤潮；东海原甲藻和米氏凯伦藻双赤潮爆发时平均温度为20.79℃,介于两者之间。2005年(偏暖)东海原甲藻爆发面积和持续时间占优势,2008年(偏冷)米氏凯伦藻先于东海原甲藻爆发而且规模也较大,全球气候变化和东海区甲藻赤潮爆发规律存在一定的关联性,同时表明了温度变化对两种甲藻赤潮演替的重要性。总之,无论是实验室模拟两种甲藻竞争结果还是现场海水表温分析结果而言,东海赤潮高发区甲藻赤潮优势种更替过程中海水温度变化起到了非常重要的作用,温度变化对两种甲藻的生长和光合生理生化等指标的研究结果也初步阐明了东海原甲藻和米氏凯伦藻种间竞争机制。通过以上结论可以初步预估当全球变暖东海区海水温度比常年升高时米氏凯伦藻赤潮爆发规模将会扩大,反之当全球变冷东海区海水温度比常年下降时东海原甲藻赤潮爆发规模将会扩大。
[Abstract]:Previous studies show that global warming, rising sea temperatures have important influence on the evolution of marine phytoplankton populations. Costatum in coastal waters of the East China Sea, p.donghaiense and Michaelis Karen algae in recent years in the East China Sea red tide algae. Mainly diatoms and dinoflagellates (often alternating diatom succession - a algae, diatoms) changes in nutrient levels dominate the succession between diatoms and dinoflagellates, but the replacement of dinoflagellate between nutrients almost at the same level, other factors (temperature, light and salinity etc.) is likely to play a decisive role in the dinoflagellate blooms and Michaelis Karen bloom according to the succession. Red tide occurrence season seawater temperature rising and seawater phosphorus concentration is low in fact, the study of different temperature (mainly temperature range of 16-28 DEG C, dinoflagellate blooms can occur) and The level of nutrients on the growth of Prorocentrum donghaiense and Michaelis Karen algae, photosynthetic characteristics and related gene expression; explore the normal levels of nutrients and salt in low phosphorus under different temperature on p.donghaiense and Michaelis Karen algae interspecific competition and the influence of p.donghaiense and Michaelis Karen algae allelopathy over the years; through the statistical analysis of correlation between sea surface temperature data and red tide outbreak, estimated global climate change scenarios (warming and cooling) of the red tide outbreak trend. The main results are as follows:
(1) the seasonal variation in simulated seawater temperature rise situation, study different culture temperatures on p.donghaiense and Michaelis Karen of algae growth, photosynthesis and the influence of the expression of Rubisco gene, results showed that the optimum growth temperature of Prorocentrum donghaiense and Michaelis Karen algae were 20 and greater than 24 DEG C, Michaelis Prorocentrum the growth rate of algae Karen; maximum photosynthesis of Prorocentrum donghaiense and Michaelis Karen algae respectively in 24 and 28 DEG C, cultivated at low temperature (16 DEG C) significantly decreased on Michaelis Karen algae photosynthesis, Prorocentrum Michaelis photosynthesis ability than Karen algae; the Rubisco gene of Prorocentrum donghaiense and Michaelis Karen was the optimal the expression of temperature were 20 and 24 degrees.
(2) through the simulation of dinoflagellate red tide occurrence season water phosphorus concentration is low situation, effects of different nutrient levels on the growth of two species of algae, culture medium (twelfth days) to add nutrients (f/2 medium) than adding nutrients than in the later stage of the experiment can significantly improve the cell concentration of two algae, simultaneous determination of nitrate and phosphate concentration, two different nutrient levels under cultivation, Prorocentrum absorption and utilization rate is not high on nitrate, phosphate uptake and utilization rate is higher, the Michaelis Karen algae on nitrate and phosphate uptake rates are very high in low phosphorus conditions. Michaelis, p.donghaiense and Karen algae growth was inhibited.
(3) in the single culture on the basis of experiment, simulation of two red tide dinoflagellate red tide in the East China Sea region on the scene, salt level normal nutrition and low phosphorus under different temperature on p.donghaiense and Michaelis Karen algae interspecific competition effect. The results show that under normal circumstances the nutrient dinoflagellates in the East China Sea low temperature (16-20 DEG C) and initial cell concentration has more advantages than dominant and Michaelis Karen algae competition, Michaelis Karen algae at high temperature (24-28 DEG C) and high initial cell concentration (0.8 * 104cells ML-1) has the absolute advantage and Prorocentrum competition in low phosphorus conditions. Under the growth rule of p.donghaiense and Michaelis Karen algae showed increased and then decreased finally or rise or suppressed decline, 16 degrees in the culture conditions in different initial cell concentration of Prorocentrum donghaiense and Michaelis Karen competition in some algae Advantage. Karen's algae have absolute advantage in the competition at the high temperature (24-28 degrees) and the original dinoflagellate in the East China Sea. Therefore, the low phosphorus condition increased the competitive advantage of Michaelis Karen algae to the original dinoflagellate.
(4) found by studying the effect of temperature on the two dinoflagellate species allelopathic effects, growth of Michaelis Karen algae filtrate of P. donghaiense produced a significant inhibition of the close relationship between temperature and cultivation of p.donghaiense and initial cell concentration, namely the cultivation of low temperature is more obvious inhibition, and Prorocentrum the higher the concentration of algal initial cell inhibition weaker, Michaelis Karen algae filtrate in allelochemicals is sensitive to heat; it also had certain inhibitory effects on the growth of Michaelis Karen algae Prorocentrum donghaiense filter, but the filtered liquid is not sensitive to heat, is related to the degree of the growth inhibition and adaptability Michaelis Karen Karen on temperature Michaelis algae algae, the optimum growth temperature by Michaelis Karen algae Prorocentrum filter liquid minimal impact, in addition, the initial cell concentration on the results will have a certain impact, low temperature low The initial concentration (16 C, 0.35 x 104cells ML-1) has a promoting effect on the growth of Karen algae, but its mechanism is not clear.
(5) according to the outbreak of Prorocentrum Michaelis and Karen bloom in the East China Sea from 2001 to 2010, when the sea surface temperature change statistical analysis showed that the dinoflagellate blooms at the outbreak of the average sea surface temperature is 20.30 DEG C, the temperature is low in red tide outbreak; Michaelis Karen bloom burst when the average sea surface temperature is 23.42 DEG C the outbreak of red tide, belongs to a relatively high temperature; Prorocentrum donghaiense and Michaelis Karen at the outbreak of red tide algae double the average temperature of 20.79 degrees, between.2005 years (warmer) HAB outbreak area and duration of dominant, 2008 (cold) Michaelis Karen before the outbreak of algal dinoflagellate and larger scale the global climate change, and the East China Sea red tide outbreak law there is a certain correlation, also shows the importance of temperature change on the two red tide dinoflagellate succession.
In short, whether it is the laboratory simulation of two dinoflagellate species competition results or seawater surface temperature analysis results, changes of seawater temperature in East China Sea red tide dinoflagellate HAB areas change of dominant species plays a very important role, the effect of temperature on the two dinoflagellate species growth and Photosynthetic Physiological and biochemical indexes of the preliminary clarify the p.donghaiense and Michaelis Karen algae interspecific competition mechanism. The above conclusions can be a preliminary estimate of global warming when the seawater temperature rises than the East China Sea region perennial Michaelis Karen bloom outbreak scale will be expanded when the global cooling in the East China Sea water temperature than normal decline dinoflagellate blooms outbreak will be expanded.

【学位授予单位】：华东师范大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：X55

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