The role of zooxanthellae in the thermal tolerance of corals: a 'nugget of hope' for coral reefs in an era of climate change
The role of zooxanthellae in the thermal tolerance of corals: a 'nugget of hope' for coral reefs in an era of climate change
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DOI：
10.1098/rspb.2006.3567
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发表时间：
2006-09-22
影响因子：
4.7
通讯作者：
van Oppen, Madeleine J. H.
中科院分区：
文献类型：
--
作者：
Berkelmans, Ray;van Oppen, Madeleine J. H.
珊瑚礁能否在全球变暖造成的预计温度上升中生存下来，将在很大程度上取决于珊瑚在今后几十年中适应或适应极端温度上升的能力。许多珊瑚物种对温度压力高度敏感，近几十年来压力（漂白）事件的数量有所增加。我们通过移植和实验操作，研究了一种常见且分布广泛的印度太平洋硬珊瑚物种Acropora millepora的驯化潜力。我们表明，成年珊瑚，至少在某些情况下，能够获得增加的耐热性和增加的耐受性是一个直接的结果，在共生体类型的变化主导他们的组织从共生藻C型到D。我们的数据表明，我们实验中共生体类型的变化是由于珊瑚组织中已经存在的现有类型的洗牌，而不是通过从环境中的外源吸收。珊瑚将其主要共生体类型改变为D（已知最耐热的类型）所获得的耐受性增加的水平约为1-1.5摄氏度。这是第一个研究表明，热驯化是因果关系的共生体类型，并提供了新的见解珊瑚窝藏混合藻类种群的生态优势。虽然这种增加对许多珊瑚物种具有巨大的生态意义，但在没有其他热适应/适应机制的情况下，可能不足以在未来100年的预测海表温度情景下生存下来。然而，在温室气体减排措施到位的同时，这可能足以“争取时间”。
The ability of coral reefs to survive the projected increases in temperature due to global warming will depend largely on the ability of corals to adapt or acclimatize to increased temperature extremes over the next few decades. Many coral species are highly sensitive to temperature stress and the number of stress (bleaching) episodes has increased in recent decades. We investigated the acclimatization potential of Acropora millepora, a common and widespread Indo-Pacific hard coral species, through transplantation and experimental manipulation. We show that adult corals, at least in some circumstances, are capable of acquiring increased thermal tolerance and that the increased tolerance is a direct result of a change in the symbiont type dominating their tissues from Symbiodinium type C to D. Our data suggest that the change in symbiont type in our experiment was due to a shuffling of existing types already present in coral tissues, not through exogenous uptake from the environment. The level of increased tolerance gained by the corals changing their dominant symbiont type to D (the most thermally resistant type known) is around 1-1.5 degrees C. This is the first study to show that thermal acclimatization is causally related to symbiont type and provides new insight into the ecological advantage of corals harbouring mixed algal populations. While this increase is of huge ecological significance for many coral species, in the absence of other mechanisms of thermal acclimatization/adaptation, it may not be sufficient to survive climate change under predicted sea surface temperature scenarios over the next 100 years. However, it may be enough to 'buy time' while greenhouse reduction measures are put in place.