辽东湾海月水母对高温低氧环境的行为响应机制

In Liaodong Bay, the moon jellyfish Aurelia sp.1 is the most common scyphozoan species and often blooms to cause detrimental effects on commercial fisheries and nuclear power plant. In preliminary studies, we have found Aurelia sp.1 frequently can appear in oxygen minimum zones and has the hypoxic tolerance during summer, resulting in high recruitment of polyp and consequent mass occurrence of jellyfish. However, the changing characteristics and adaptive strategies of reproductive behavior of Aurelia sp.1 in response to high temperature and hypoxia stresses are unknown, and the spatiotemporal pattern in distribution of Aurelia sp.1 in Liaodong Bay is also unclear. With the method of aquatic organism behavioral research and species distribution models, we will throughout this project, explore the recruitment modes of polyp population based on sexual and asexual reproduction: (1) investigate the ecophysiological response, such as swimming behavior, survival, and settlement of planula, and development of settled polyps, in high temperature and hypoxia conditions. 2) Compare the different asexual reproductions of polyps on an individual basis at high temperature and hypoxia. 3) Clarify the effects of temperature on the distribution area of Aurelia sp.1 in Liaodong Bay. The results of this study should be essentially used in clarifying the seasonal change of population and the adaptive strategy in different life stages, and revealing the outbreak mechanism, and would help in determining the probability of future bloom development and in installing effective means and ways of countermeasures, and provide a scientific basis for strengthening early warning.

海月水母(Aurelia sp.1)是辽东湾常见的钵水母种类，对环境的适应特性使其在夏季低氧区内获得竞争优势，形成暴发现象，给沿岸渔业经济和核电安全造成巨大影响。在我们前期研究中发现，海月水母能够耐受高温低氧的环境，其行为及无性繁殖方式受环境影响显著，但目前关于在高温低氧下的行为响应机制及温度升高对辽东湾海月水母分布的影响尚不清楚。本项目聚焦高温低氧对海月水母的繁殖行为及分布变化的影响，拟采用行为生态学等技术手段，研究海月水母浮浪幼虫在高温低氧环境下的运动行为及适应性特征；阐明高温低氧下海月水母无性繁殖方式的选择及贡献差异，明确不同繁殖行为对高温低氧环境的适应性机制。在此基础上，运用物种分布模型研究温度升高对水母体在辽东湾分布的短期及长期的潜在影响。研究结果对查明海月水母的季节性动态变化，深入了解生活史各阶段的适应性对策及暴发机理具有重要意义，为海月水母暴发预警及有效治理提供科学依据。

海月水母是辽东湾常见的钵水母种类，对环境的适应特性使其在海区获得竞争优势，形成暴发现象，给沿岸渔业经济造成巨大损失。本项目通过室内受控实验和野外现场调查相结合的方式研究了海月水母对环境条件变化的响应机制。采用逐个观察与宏观数量统计相结合的方式，确定了温度及溶解氧影响下浮浪幼虫的行为变化特征，揭示了高温低氧条件下浮浪幼虫的行为响应模式，证明了在高温低氧条件下海月水母浮浪幼虫有能力迅速附着以扩张螅状体种群。通过对螅状体繁殖行为的观察，定性和定量的分析了螅状体不同无性繁殖方式产生的原因，发生时间，产生条件等；在螅状体繁殖行为观察的基础上，进一步明确了温度对螅状体无性繁殖方式及繁殖与生长上能量分配的调控模式。通过环境因子对碟状体存活生长的实验研究，查明了海月水母碟状体最适的温盐范围，深入研究了碟状体可耐受的温盐极限。从浮游态到底栖固着态再到浮游态的不同时期，揭示了环境变化调控水母种群数量变动的根源。同时进一步探索了海月水母体在辽东湾的分布及影响因素，研究结果对查明海月水母的季节性动态变化，深入了解生活史各阶段的适应性对策及暴发机理具有重要意义。