英国南安普顿大学Jörg Wiedenmann等研究人员发现，造礁珊瑚靠光合共生体养殖和进食。相关论文于2023年8月23日在线发表在《自然》杂志上。

研究人员通过一系列长期实验表明，仅靠共生体吸收溶解的无机氮和磷就足以维持珊瑚的快速生长。接下来，考虑到宿主和共生体的氮和磷预算，研究人员确定这些营养物质是通过共生体“养殖”收集的，并通过消化多余的共生体细胞转移到宿主体内。最后，研究人员利用一个大规模的自然实验（在该实验中，海鸟为一些珊瑚礁施肥，但不为其他珊瑚礁施肥）来说明，研究人员在实验室实验中建立的共生珊瑚对溶解的无机营养物质的有效利用有可能在生态系统层面上促进野生珊瑚的生长。以共生体为食使珊瑚动物能够利用一个重要的营养库，并有助于解释共生珊瑚在营养有限的水域中取得演化和生态成功的原因。

据介绍，珊瑚礁是高度多样化的生态系统，但却能在缺乏营养的水域中茁壮成长，这种现象经常被称为达尔文悖论。珊瑚动物宿主的能量需求通常可以通过其藻类共生体过量生产富含碳的光合产物来完全满足。然而，人们对珊瑚从其共生体中获取氮和磷等重要营养物质的机制还不完全了解。

附：英文原文

Title: Reef-building corals farm and feed on their photosynthetic symbionts

Author: Wiedenmann, Jrg, DAngelo, Cecilia, Mardones, M. Loreto, Moore, Shona, Benkwitt, Cassandra E., Graham, Nicholas A. J., Hambach, Bastian, Wilson, Paul A., Vanstone, James, Eyal, Gal, Ben-Zvi, Or, Loya, Yossi, Genin, Amatzia

Issue&Volume: 2023-08-23

Abstract: Coral reefs are highly diverse ecosystems that thrive in nutrient-poor waters, a phenomenon frequently referred to as the Darwin paradox1. The energy demand of coral animal hosts can often be fully met by the excess production of carbon-rich photosynthates by their algal symbionts2,3. However, the understanding of mechanisms that enable corals to acquire the vital nutrients nitrogen and phosphorus from their symbionts is incomplete4,5,6,7,8,9. Here we show, through a series of long-term experiments, that the uptake of dissolved inorganic nitrogen and phosphorus by the symbionts alone is sufficient to sustain rapid coral growth. Next, considering the nitrogen and phosphorus budgets of host and symbionts, we identify that these nutrients are gathered through symbiont ‘farming’ and are translocated to the host by digestion of excess symbiont cells. Finally, we use a large-scale natural experiment in which seabirds fertilize some reefs but not others, to show that the efficient utilization of dissolved inorganic nutrients by symbiotic corals established in our laboratory experiments has the potential to enhance coral growth in the wild at the ecosystem level. Feeding on symbionts enables coral animals to tap into an important nutrient pool and helps to explain the evolutionary and ecological success of symbiotic corals in nutrient-limited waters.

DOI: 10.1038/s41586-023-06442-5

Source: https://www.nature.com/articles/s41586-023-06442-5