The ecological distribution and comparative photobiology of symbiotic dinoflagellates from reef corals in Belize: Potential implications for coral bleaching
The ecological distribution and comparative photobiology of symbiotic dinoflagellates from reef corals in Belize: Potential implications for coral bleaching
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伯利兹珊瑚礁共生甲藻的生态分布和比较光生物学：对珊瑚白化的潜在影响
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发表时间：
2006
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通讯作者：
Rebecca M. Thur
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作者：
M. Warner;T. Lajeunesse;Jennifer D. Robison;Rebecca M. Thur
对伯利兹珊瑚礁 1‐25 m 深度范围内的八种常见珊瑚礁物种进行了共生藻属甲藻的光生物学和分布研究。使用内部转录间隔区 2 区域的聚合酶链反应变性梯度电泳对共生体进行遗传鉴定，揭示了某些共生体类型在宿主特异性和深度分区方面的显着差异。发现每个宿主分类单元都与该地区存在的有限的共生体子集相关。种内变异在较浅的地点（1-8 m）最大，其中多达五个独特的共生体分布在单个宿主群体中（例如 Montastraea faveolata）。在深度（15-25 m），群落之间的差异很小，其中一种藻类类型与一个物种的大多数或所有群落相关。光系统 II (PSII) 的最大光化学效率和光适应效率通过活性叶绿素荧光测定，并用于评估光合潜力的潜在差异。在正常环境条件下，在特定深度的同一珊瑚物种中发生的不同共生体之间几乎没有或没有注意到生理差异，但在同一深度的珊瑚物种之间注意到 PSII 效率的种间差异。短期漂白实验表明，与滨珊瑚中的 A4a 共生体相比，M. faveolata 中的共生体 B1 和 C7 经历了更高程度的热诱导光抑制。在 M. faveolata 中观察到的 PSII 失活的差异模式可以通过该珊瑚中存在不同的共生体种群来解释。一些珊瑚内共生体之间 PSII 的原位最大激发压力的差异可以提供不同物种的珊瑚或具有不同共生体的单个菌落如何响应自然热应激事件的预测性测量。
The photobiology and distribution of dinoflagellates in the genus Symbiodinium was investigated for eight common reef coral species over a depth range of 1‐25 m on a coral reef in Belize. The genetic identification of symbionts using polymerase chain reaction‐denaturing gradient electrophoresis of the internal transcribed spacer 2 region revealed marked differences in host specificity and depth zonation for certain symbiont types. Each host taxon was found to associate with a limited subset of symbionts that exist in the region. Intraspecific variation was greatest at the shallower sites (1‐8 m), where as many as five distinctive symbionts were distributed among a single host population (e.g., Montastraea faveolata). At depth (15‐25 m), variation from colony to colony was minimal, where one algal type associated with most or all the colonies of a species. The maximal photochemical efficiency and light‐acclimated efficiency of photosystem II (PSII) were determined by active chlorophyll fluorescence and used to assess potential differences in photosynthetic potential. Under normal ambient conditions, little or no physiological differences were noted among different symbionts occurring in the same species of coral at a particular depth, yet interspecific differences in PSII efficiency were noted between coral species at the same depth. Short‐term bleaching experiments showed that symbionts B1 and C7 within M. faveolata experienced a higher degree of thermally induced photoinhibition relative to A4a symbionts in Porites astreoides. The differential patterns of PSII inactivation observed within M. faveolata could be explained by the presence of different symbiont populations within this coral. Differences in in situ maximum excitation pressure on PSII between symbionts within some corals may provide a predictive measure of how different species of coral or individual colonies with different symbionts would respond to natural thermal stress events.