基于钵水母生活史的种群动力学模型研究

发布时间：2018-02-20 08:06

本文关键词： 钵水母生活史暴发机理沙蜇横裂基质 PM模型 CPM模型海洋食物网模型　出处：《东北师范大学》2017年博士论文　论文类型：学位论文

【摘要】：近年来,水母暴发给人们的生产生活及海洋生态系统带来严重影响,成为继有害藻华之后最大的海洋生态灾害.水母数量激增源于它复杂的生活史,对于大多数钵水母而言,没有了海底水螅体的补充,再适宜的理化生环境都与其无关,海底水螅体的存在是水母暴发的充分条件.建立和研究水母生活史模型是揭示水母暴发机理的第一步也是关键一步.本文重点研究受理化环境影响的钵水母生活史模型,通过定性分析及数值模拟揭示横裂、萌发等关键过程对水母生活史各阶段的影响以及诱发水母数量激增的关键环境因子;在此基础上建立水母与浮游生物及鱼类的食物网模型,讨论各功能群与水母暴发的内在联系,揭示海底阶段对水母暴发及整个浮游生态群落的影响.本文首先给出了一般的钵水母生活史模型(PM模型),讨论了温度、天敌及基质变化对水母种群的影响.相比于天敌的减少,系统对海底基质的扩张更加敏感,海底阶段对种群数量的激增具有重要贡献;在一定范围内,温度增加将导致水媳体和水母数量增加,但过高的温度对二者都是有害的.本文随后研究了严重困扰东亚海域的巨型水母——沙蜇的生活史模型(CPM模型),为了揭示足囊休眠与萌发对沙蜇种群的影响,先后建立了常数时滞、分布时滞及考虑海底密度制约效应的泛函微分方程模型.研究表明随着足囊休眠时间的增加,系统经历Hopf分支从稳定到振荡;足囊的波动可引起水螅体的波动,但对水母体影响不大.文中结合大连附近海域表层水温的数据变化,指出温度和休眠时间共同影响足囊的数量变化;足囊的休眠与萌发不应成为水母暴发的关键因素.参数敏感性分析刻画了水螅体对基质扩张最为敏感,而水母体数量受横裂率影响最明显.此外,控制近海人为基质的扩张,可以避免海底阶段生活空间的提升,从而避免温度增加所引起的横裂率增加,同时降低浮浪幼体的存活率,增加水螅体的竞争率,进而降低沙蜇各阶段的数量,是有效可行的控制策略.水母大范围暴发是一个不争的事实,目前争论的焦点在于水母的增加是一种趋势?还是仅仅为一种周期性振荡?本文在最后建立了基于水母生活史的四维食物网模型,分析指出横裂率的增加并不总是对水母有利;藻类大量聚集将引起水母数量的增加;当控制横裂率,同时适当降低藻类增长率时,不仅水母数量可以得到控制,鱼类资源也可以得到恢复.数值分析不仅展现了水母数量的周期性振荡,而且给出了保护和恢复鱼类资源的控制策略.本文通过数学模型,刻画水母生活史,揭示环境因子对生活史各阶段的影响、关键过程和暴发机理;并将生活史耦合进食物网模型中,揭示生活史的关键过程对水母暴发的影响、藻华与水母暴发的内在联系、以及水母暴发对鱼类及整个海洋生态系统的影响.通过本文的研究,我们试图为水母暴发的机理研究提供新的模型和研究思路,为控制水母暴发及鱼类资源恢复提供相应的理论策略.
[Abstract]:In recent years, jellyfish bloom bring serious influence to the production and life of people and the marine ecosystem, become marine ecological disaster after the harmful algal blooms. The largest jellyfish due to the surge in the number of its complex life history, for most scyphozoan, no added submarine polyps, and appropriate physical and chemical environment and regardless of the existence of submarine hydra is a sufficient condition for the establishment and research of jellyfish bloom. The jellyfish life history model is the first step to reveal the mechanism of jellyfish bloom is a key step. This paper focuses on the acceptance of scyphomedusae life history model of environmental impact, through qualitative analysis and numerical simulation of transverse crack, the key influence on the germination process each stage of jellyfish life history and jellyfish induced surge in the number of key environmental factors; on the basis of the establishment of jellyfish and plankton and fish food web model, discuss the work Can the internal contact group and jellyfish bloom, reveal the effect of submarine stage of jellyfish bloom and the planktonic ecological community. This paper first gives the scyphomedusa life history general model (PM model), discussed the effect of changes in temperature, natural enemies and matrix on the jellyfish population. Reduce compared to natural enemies, the system is more sensitive to expansion submarine matrix, submarine stage has an important contribution to the surge in population; in a certain range, the temperature will lead to increase the quantity of water body and daughter-in-law jellyfish increased, but the high temperature is harmful to the two. This paper studied the life history model of mega - nemopilema nomurai plagued the East Asian sea jellyfish (CPM model), in order to reveal the Podocyst effect on Dormancy and germination of nemopilema nomurai population, has established a constant time delay, distributed delay and functional differential equation model of submarine density. The results show that with the consideration of the effect Increase the Podocyst sleep time, the system undergoes a Hopf bifurcation from steady to oscillatory; Podocyst fluctuations can cause polyp fluctuations, but has little effect on Medusa. Combining near Dalian sea surface temperature data changes in the text, pointed out that the temperature and time effect of changes in the number of dormant common Podocyst; Podocyst dormancy and should not become a key factor in the germination of jellyfish blooms. The sensitivity analysis of parameters characterize the polyp was most sensitive to the matrix expansion, and the number of Medusa by the cross crack rate is the most obvious influence. In addition, the offshore artificial control matrix expansion, can avoid the bottom stage of life space, so as to avoid the temperature caused by the increase of the transverse crack the rate of increase, and reduce the survival rate of planula, increase polyp competition rate, thereby reducing the number of stages of nemopilema nomurai, the control strategy is feasible and effective. A wide range of jellyfish outbreaks is an indisputable The fact that the focus of the debate in the increase of jellyfish is a trend? Or just a periodic oscillation? At the end of this paper established a four-dimensional food web model of jellyfish life history based on the analysis pointed out that the transverse crack rate increase is not always favorable to jellyfish; algae aggregation will lead to increased number of jellyfish; when control of transverse crack rate, lowering the algae growth rate, not only the number of jellyfish can be controlled, fish resources can also be restored. Numerical analysis not only shows the periodic oscillation of the number of jellyfish, and presents the control strategy of the protection and restoration of fish resources. Through the mathematical model, describe the jellyfish life history, revealing the environmental factor effects of the various stages of the life cycle and the key process and outbreak mechanism; and the life history of coupled into the food web model, reveals the key processes affecting life history of jellyfish outbreaks, Relationship of algal blooms and jellyfish bloom, and jellyfish bloom effect on fish and the marine ecosystem. Through this research, model and provide new research ideas for mechanism research we try to provide the theory of jellyfish blooms, the corresponding strategies to restore control of jellyfish blooms and fish resources.

【学位授予单位】：东北师范大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：O175

【相似文献】