Sarah Vitak: This is Scientific American’s 60-Second Science. I’m Sarah Vitak.
这里是《科学美国人》的60 秒科学。我是莎拉·维塔克。
Charles Darwin’s famous trip on the HMS Beagle is primarily known for bringing us the concept of evolution. But Darwin also investigated coral reefs and their formation. One thing about reefs in particular really confused him—that conundrum became known as Darwin’s reef paradox. The paradox is this:
查尔斯·达尔文(Charles Darwin)那场举世闻名的小猎犬号(HMS Beagle)之旅主要给世人带来了“演化”这一生物概念。但是，达尔文还调查了珊瑚礁及其形成过程，其中有一个现象确实困扰过他，这一难题后来成为了达尔文珊瑚礁悖论(Darwin's reef paradox)，具体如下：
Voolstra: How can you find this lush, teeming of life in the otherwise, nutrient depleted ocean.
在营养匮乏的海洋中，为什么会存在这般生机盎然、欣欣向荣的生命呢?
Vitak: That’s Dr. Christian Voolstra, a professor at the University of Konstanz in Germany.
克里斯蒂安·福尔施特拉是德国康斯坦茨大学教授。
Voolstra: And the trick is symbiosis. Corals are basically sessile organisms or animals, so they basically pick a place and they sit and then they cannot move. So the way they make a living is that they team up with micro algae inside the tissues. And this is essentially tiny plants that do photosynthesis. And this photosynthesis generates sugars. And these sugars will be essentially delivered to the coral animals.
秘密就在于共生关系。珊瑚基本上都是固着生物或者说动物，所以一旦选定了某地，它们就留在那里，不再移动。它们的生存方式就是和组织中的微型藻类搭伙，这些微小的植物能通过光合作用产生糖分，绝大部分都会输送给珊瑚。
Vitak: These little critters across the globe are in great peril a lot of danger. According to a report from the Global Coral Reef Monitoring Network published in October 2021, we lost 14% of the world’s coral reefs in the last decade. This was mostly due to large scale bleaching events. Coral bleaching is triggered by changes in the coral's environment—including increased temperature, sunlight, or pollutants. But what exactly does it mean for coral to be bleached?
然而，全球各地的这些小动物正陷入巨大的生存危机。根据全球珊瑚礁监测网(Global Coral Reef Monitoring Network)2021 年 10 月发布的报告，过去十年内，我们损失了全球 14% 的珊瑚礁，主要原因是白化事件。珊瑚白化的导火索是珊瑚生存环境的变化，包括温度升高、阳光辐射或者污染。但珊瑚白化究竟意味着什么?
Voolstra: The color of corals comes from the photosynthetic pigments of the algae. So the minute these algae are out, the coral looks white. So what happens in bleaching is that these symbiotic algae or tiny plant cells are getting expelled out of the coral tissue.
珊瑚的颜色来自藻类光合作用的色素，珊瑚一旦失去藻类，就会发白。所谓的白化就是这些共生的藻类或者微小植物细胞在珊瑚组织里消失殆尽。
If the environmental conditions actually become better again, they can actually take up their algae again and they are fine. So this is a transitory state. But In actuality, if the environmental conditions persist, the coral literally starves to death.
倘使环境条件真能得到改善，藻类在珊瑚中重获繁荣，一切便会转危为安，所以，这是一种可逆的过渡状态，但现实中，倘若环境条件继续恶化，珊瑚就会被活活饿死。
Vitak: Dr. Voolstra and his team were really interested in research that took a new approach to helping coral cope with increased ocean temperatures: treating them with probiotics. [Christian R. Voolstra et al., Extending the natural adaptive capacity of coral holobionts]
福尔施特拉博士团队对这一研究方向非常感兴趣，他们用到了新的方法来帮助珊瑚应对逐渐升温的海洋：：用益生菌来疗养珊瑚。[Christian R. Voolstra 等人，扩展珊瑚全生物的自然适应能力]
Voolstra: The general consumer knows that you can buy yogurt with probiotic cultures, right? There are some bacteria that are good for your gut.
普通消费者都知道，我们能在超市里买到含有益生菌的酸奶，某些细菌有益于我们的肠道健康。
Vitak: Just like humans, coral have a microbiome; a community of microorganisms that live on or inside them. Previous work had shown that bolstering the coral’s bacterial microbiome by giving them doses of probiotics helped them survive challenging conditions. The process is similar to how we work with microbiomes and probiotics in people.
就和人类一样，珊瑚也有微生物组：一群生活在珊瑚表面或者内部的微生物群落。先前的研究已经表明，为珊瑚供给一定剂量的益生菌以支持珊瑚的微生物菌群落，能够帮助珊瑚在充满挑战的环境下生存下来，这一过程类似于人体摄入微生物组和益生菌。
Voolstra: You extract microbes from these very resilient individuals, and then you literally transplant them or offer them to less resilient individuals of the same coral species. So it's not that you're putting something there that wasn't there, but it's really like this human fecal transplants. You have a healthy donor, and you offer these bacteria to an affected recipient.
从复原能力强劲的珊瑚个体中提取出微生物，然后直接将它们移植或提供给同一珊瑚物种中复原能力较弱的个体。所以不是说放了一些原本没有的东西进去，而是非常像人类的粪便移植。我们拥有健康供体，将这些健康细菌提供给健康有损的一方。
Vitak: This had already been shown as a proof of concept in previous research. But Dr. Voolstra and his team wanted to drill down and understand it a bit better.
在先前的研究中，这一做法已得到概念性证明，福尔施特拉团队想进行更深入的调查，以求透彻理解。
To do the experiment, they worked in what they call “mesochosms”—sort of a sweet spot between a sterile isolated lab setting and a totally wild reef setting. Basically, they had aquariums with multiple types of corals and some other critters. This allowed them to control conditions but also get a slightly more real-world result.
为了展开实验，他们用到了“围隔实验”(mesocosm)环境，一种介于无菌隔离实验室和完全野生珊瑚礁环境之间的最佳实验环境。具体来说，他们在水缸中饲养了多种类型的珊瑚以及一些其他小动物，这让他们能够控制实验条件，同时获得更接近现实世界的结果。
One very convenient thing about working with coral is that they are colonial organisms.
而研究珊瑚的一大便利之处在与珊瑚是群体生物。
Voolstra: Which means that they consist of repetition of the same building blocks. From one colony, you can generate many, many fragments or pieces that all have the exact same genotype with this exact same environmental history. And then you can put them into different conditions.
这表明它们由重复的构建模块组成，取其中一小块，便可以生成许多许多片段，这些片段都拥有完全相同的基因型和环境史。然后，你可以把它们放入不同环境条件中。
Vitak: Once they had their fragments they treated some of them with a mixture of bacteria that they had carefully isolated, selected, and grown from resilient coral—and, of course, they wanted to have a control for their experiment as well, so they gave some a placebo saline solution.
一旦团队获得了自己的生物片段，他们就会用细菌混合物来进行处理，这些细菌由团队精心分离、选择出来，来自复原能力强的珊瑚。当然，还得有对照组，于是他们给其中一部分珊瑚提供了一些安慰剂盐溶液。
Finally, they slowly cranked up the heat to simulate ocean warming.
最后，他们慢慢提高热量以模拟海洋变暖的过程。
Voolstra: And this was a very long experiment that essentially lasted over 75 days.
这是一个非常长的实验，一共持续了75天以上。
Vitak: What they found was fascinating. All the coral showed signs of bleaching as the temperature increased, but the coral treated with probiotics recovered faster. And they were 40% more likely to survive.
他们的发现相当奇妙。随着温度的升高，所有珊瑚都表现出白化的迹象，但是接受了益生菌的珊瑚恢复得更快些，生存几率也增加了40%。
Voolstra: Okay, like as a coral biologist, or as a biologist, in general, I think you're usually very happy if you have a 5% effect or something observable that you can count with reasonable numbers. This is massive. I mean, if you almost double the survivorship, this is huge.
好吧，就像作为珊瑚生物学家，或者作为生物学家，一般来说，我认为如果你有5%的影响或可以用合理数字计算的可观察到的东西，想必会很高兴。这次的数字相当巨大，我的意思是，如果能将这一存活率翻一番，这个数字可以算是非常大了。
Vitak: The team also looked at how adding this probiotic cocktail changed the coral’s microbiome and—how it changed the coral itself. Adding the probiotic changed the composition of the coral’s microbiome.
团队还调查了添加这一益生菌混合物如何改变珊瑚的微生物组，又如何改变珊瑚本身。添加益生菌改变了珊瑚微生物组的组成。
Voolstra: It also instigated a change in the expression of certain genes in the coral host. And those genes, were really kind of the go-to genes that you would bet on if this is for increased recovery.
而且还引发了珊瑚宿主体内特定基因表达的改变。如果是为了增强恢复力，那你真会打赌就是这些基因了。
Vitak: So basically—things like repair genes, immunity genes, and stress response genes.
所以具体来说，就是修复基因、免疫基因和应激反应基因。
Voolstra: So this is kind of the cliffhanger of this study, you actually change stuff in the host. And in the correlate host, and we don't know how long these changes will stay on. Of course, if those changes can be kept long term, you would not need to keep this probiotic treatment going on and on, right?
这也是这项研究留下的悬念，你实际上改变了宿主体内的一些东西，而我们不知道这些变化会留存多久，如果能够长期保持，你将不再需要重复益生菌疗法了，不是吗?
Vitak: Which would be amazing in terms of translating this to the real world.
那到时候将这个消息传递给现实世界时，一定会非常有意思。
Voolstra: I mean, there’s 300,000 square kilometers of coral reef. There's billions of coral. So if you want to bring a little magic potion underwater and inoculate each coral, this becomes unmanageable. No organism makes a living in isolation. And I think we're just getting better at understanding this.
我想说，地球上有30万平方千米的珊瑚礁，数十亿的珊瑚。所以，如果你想要在水下撒上一点魔法灵药，让每一个珊瑚都能‘接种’到，那么结果可能无法控制。在这个星球上，没有一种生物可以完全与世隔绝，独自存活，我想我们现在对这一点的理解也越来越深刻了。
Vitak: Thanks for listening. For Scientific American’s 60 Second Science, I’m Sarah Vitak.
感谢收听。以上是《科学美国人》的60秒科学，莎拉·维塔克报道。
Sarah Vitak: This is Scientific American’s 60-Second Science. I’m Sarah Vitak.
Charles Darwin’s famous trip on the HMS Beagle is primarily known for bringing us the concept of evolution. But Darwin also investigated coral reefs and their formation. One thing about reefs in particular really confused him—that conundrum became known as Darwin’s reef paradox. The paradox is this:
Voolstra: How can you find this lush, teeming of life in the otherwise, nutrient depleted ocean.
Vitak: That’s Dr. Christian Voolstra, a professor at the University of Konstanz in Germany.
Voolstra: And the trick is symbiosis. Corals are basically sessile organisms or animals, so they basically pick a place and they sit and then they cannot move. So the way they make a living is that they team up with micro algae inside the tissues. And this is essentially tiny plants that do photosynthesis. And this photosynthesis generates sugars. And these sugars will be essentially delivered to the coral animals.
Vitak: These little critters across the globe are in great peril a lot of danger. According to a report from the Global Coral Reef Monitoring Network published in October 2021, we lost 14% of the world’s coral reefs in the last decade. This was mostly due to large scale bleaching events. Coral bleaching is triggered by changes in the coral's environment—including increased temperature, sunlight, or pollutants. But what exactly does it mean for coral to be bleached?
Voolstra: The color of corals comes from the photosynthetic pigments of the algae. So the minute these algae are out, the coral looks white. So what happens in bleaching is that these symbiotic algae or tiny plant cells are getting expelled out of the coral tissue.
If the environmental conditions actually become better again, they can actually take up their algae again and they are fine. So this is a transitory state. But In actuality, if the environmental conditions persist, the coral literally starves to death.
Vitak: Dr. Voolstra and his team were really interested in research that took a new approach to helping coral cope with increased ocean temperatures: treating them with probiotics. [Christian R. Voolstra et al., Extending the natural adaptive capacity of coral holobionts]
Voolstra: The general consumer knows that you can buy yogurt with probiotic cultures, right? There are some bacteria that are good for your gut.
Vitak: Just like humans, coral have a microbiome; a community of microorganisms that live on or inside them. Previous work had shown that bolstering the coral’s bacterial microbiome by giving them doses of probiotics helped them survive challenging conditions. The process is similar to how we work with microbiomes and probiotics in people.
Voolstra: You extract microbes from these very resilient individuals, and then you literally transplant them or offer them to less resilient individuals of the same coral species. So it's not that you're putting something there that wasn't there, but it's really like this human fecal transplants. You have a healthy donor, and you offer these bacteria to an affected recipient.
Vitak: This had already been shown as a proof of concept in previous research. But Dr. Voolstra and his team wanted to drill down and understand it a bit better.
To do the experiment, they worked in what they call “mesochosms”—sort of a sweet spot between a sterile isolated lab setting and a totally wild reef setting. Basically, they had aquariums with multiple types of corals and some other critters. This allowed them to control conditions but also get a slightly more real-world result.
One very convenient thing about working with coral is that they are colonial organisms.
Voolstra: Which means that they consist of repetition of the same building blocks. From one colony, you can generate many, many fragments or pieces that all have the exact same genotype with this exact same environmental history. And then you can put them into different conditions.
Vitak: Once they had their fragments they treated some of them with a mixture of bacteria that they had carefully isolated, selected, and grown from resilient coral—and, of course, they wanted to have a control for their experiment as well, so they gave some a placebo saline solution.
Finally, they slowly cranked up the heat to simulate ocean warming.
Voolstra: And this was a very long experiment that essentially lasted over 75 days.
Vitak: What they found was fascinating. All the coral showed signs of bleaching as the temperature increased, but the coral treated with probiotics recovered faster. And they were 40% more likely to survive.
Voolstra: Okay, like as a coral biologist, or as a biologist, in general, I think you're usually very happy if you have a 5% effect or something observable that you can count with reasonable numbers. This is massive. I mean, if you almost double the survivorship, this is huge.
Vitak: The team also looked at how adding this probiotic cocktail changed the coral’s microbiome and—how it changed the coral itself. Adding the probiotic changed the composition of the coral’s microbiome.
Voolstra: It also instigated a change in the expression of certain genes in the coral host. And those genes, were really kind of the go-to genes that you would bet on if this is for increased recovery.
Vitak: So basically—things like repair genes, immunity genes, and stress response genes.
Voolstra: So this is kind of the cliffhanger of this study, you actually change stuff in the host. And in the correlate host, and we don't know how long these changes will stay on. Of course, if those changes can be kept long term, you would not need to keep this probiotic treatment going on and on, right?
Vitak: Which would be amazing in terms of translating this to the real world.
Voolstra: I mean, there’s 300,000 square kilometers of coral reef. There's billions of coral. So if you want to bring a little magic potion underwater and inoculate each coral, this becomes unmanageable. No organism makes a living in isolation. And I think we're just getting better at understanding this.
Vitak: Thanks for listening. For Scientific American’s 60 Second Science, I’m Sarah Vitak.
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