内容来源：https://www.quantamagazine.org/corals-spin-tiny-vortices-to-get-oxygen-but-not-if-its-too-hot-20260805/

内容总结：

在看似宁静的海面之下，珊瑚其实正在进行一场关乎生存的“生死时速”。一项最新研究揭示，珊瑚并非被动的岩石，而是依靠其表面微小的纤毛主动制造漩涡，为自己获取氧气。然而，当海水温度过高时，这套精密的“呼吸系统”反而会失效，甚至成为珊瑚的“催命符”。

长期以来，科学家认为珊瑚只是被动地依赖水的自然扩散来获取养分和氧气。但2014年的一项突破性研究发现，珊瑚表面的毛发状纤毛会快速摆动，在边界层制造出微小的漩涡，主动将含氧海水输送到自身组织，同时清除沉积物。这种机制对夜间的珊瑚至关重要，因为此时为其提供氧气的共生藻类会停止光合作用。

然而，由哥本哈根大学等机构科学家合作完成、发表于《科学》杂志的最新研究显示，纤毛的“工作强度”与水温密切相关。实验发现，当水温升高时，水的溶氧量下降，珊瑚为了获取更多氧气，会加速纤毛的摆动，如同“水下喘息”。但当水温逼近37摄氏度时，纤毛运动开始减缓；一旦超过39摄氏度，纤毛活动彻底停止，珊瑚随即死亡。

科学家解释说，问题的关键在于，高温下珊瑚的新陈代谢加快，耗氧量急剧上升，其速度超过了纤毛搅动水流补充氧气的效率。此时，纤毛的疯狂摆动不仅无济于事，反而会消耗组织内宝贵的氧气，导致珊瑚在缺氧环境中窒息而亡。

这一发现为理解珊瑚白化提供了全新视角。以往，科学家多用共生藻的状态判断珊瑚健康，而纤毛活动或许能更直接地反映珊瑚的生存状况。研究团队指出，这或许能解释为何在同一片礁石上，有的珊瑚白化死亡，而邻近的个体却能幸存——这可能与局部水流状况和纤毛工作效率的差异有关。

研究还首次揭示了纤毛运动的复杂性：每个珊瑚息肉上的纤毛按六边形排列，协同运动，产生类似开瓶器的螺旋水流，精准地将营养物质送入口部，同时推开废物颗粒。

研究者强调，随着气候变暖加剧，海水缺氧对珊瑚的威胁可能被严重低估。长期以来，海洋酸化和高温被视为珊瑚的头号杀手，但这项研究提示，脱氧作用或许才是引发珊瑚大面积死亡的“根本元凶”。科学家坦言，我们正在“拼命追赶”对珊瑚生存机制的认识，而这一新发现，可能将彻底改写既有的珊瑚保护理论。

中文翻译：

珊瑚制造微小漩涡获取氧气，但温度过高时则无法做到

引言

乍一看，珊瑚不过是色彩斑斓的岩石——一堆堆叶瓣、石笋和枝杈从海床中伸出。

但它们绝非如此。珊瑚是形成持久群落的复杂生物，与其他动物一样，它们也需要氧气才能生存。在珊瑚的活体表面，一场求生的激烈舞蹈正在上演，这一幕肉眼无法看见，在2014年之前也不为科学界所知。那些微小的舞者是毛发状的纤毛，而对这些微型结构的新研究正揭示出珊瑚在决定自身命运方面有多么主动。

珊瑚并不幸运地拥有稳定的氧气供应，也无法移动位置去寻找氧气。白天，构成珊瑚群落的微小珊瑚虫依靠组织内进行光合作用的共生藻类获得充足氧气。但到了夜晚，这一过程停止，珊瑚虫唯一的氧气来源便是周围的水体。此时，纤毛面临生死抉择。借助科学家仍在努力理解的机制，纤毛摆动起来，产生快速流动的水漩涡，将氧气输送到珊瑚的外层组织，同时也有助于保持群落不被沉积物覆盖。

2026年5月发表在《科学》杂志上的一项研究提供了新的洞见，揭示了没有大脑或肌肉骨骼系统的生物如何产生并调控这一过程——以及当周围水体变暖时会发生什么。较温暖的水体天然携带更少的氧气，这促使珊瑚越来越快地摆动纤毛，仿佛在喘息。超过一定温度后，这一系统开始适得其反；纤毛的剧烈摆动消耗掉珊瑚组织所能吸收的所有氧气，随后珊瑚虫便可能在含氧量更低的水体中窒息。

生物物理学家、海洋生物学家、数学家和建模人员目前正在合作，以更好地理解其中发挥作用的生理学和流体力学力量，以及它们与白化现象、珊瑚疾病和大规模死亡之间的关联。

这种动态图景对科学家来说有些新鲜，他们长期以来一直将珊瑚的共生藻类伙伴视为珊瑚健康状况的指标。纤毛可能提供更直接的信号，德国康斯坦茨大学研究珊瑚应激生物标志物和基因组学的海洋生物学家蕾切尔·阿尔德迪斯表示，她未参与这项研究。“正是这些更细微的细节，可以帮助我们理解为什么有些珊瑚会白化而另一些不会，（即使）它们紧紧挨在一起。”

漩涡求生

每个珊瑚群落都被一层薄薄的水边界层所包裹，该边界层的运动因珊瑚表面的摩擦而减慢。研究人员曾假设珊瑚相对于缓慢移动的边界层是被动的，仅仅依靠自然扩散来获取营养和氧气。

美国国家海洋保护区

随后在2014年，来自麻省理工学院和魏茨曼科学研究所的一个团队发表了具有开创性的研究，表明珊瑚纤毛通过与边界层相互作用，快速抽动以产生新鲜含氧海水的漩涡。直到十年前，科学家还认为纤毛只是用来移动黏液、扫除废物颗粒和其他碎屑的扫帚。这项研究不仅首次模拟了纤毛产生的微小漩涡，还揭示了纤毛对生存和新陈代谢的重要性。

起初，曾在麻省理工学院以博士后研究员身份领导2014年研究工作的微生物学家和环境工程师奥尔·夏皮罗感兴趣的是，感染珊瑚并引发疾病的微生物如何遵循浓度梯度移动，这一过程被称为趋化性。在显微镜下，他注意到了一些奇怪的现象：在边界层中，颗粒在旋转并混合在一起——完全不像他原本预期的那种被动扩散。

“对我来说，而且我认为后来对整个领域来说，这都是一种范式转变，”夏皮罗说，他目前是以色列沃尔卡尼研究所的研究员。很明显，边界层并非静止的，而是一个动态区域，纤毛在其中制造着自己的湍流。这一发现启发了夏皮罗的团队转向一个旁支课题，绘制纤毛将氧气输送到珊瑚组织的路径。“这真正改变了我们对这一（微）环境的理解，因为突然间扩散变得不再重要了，”夏皮罗说。

扩散是营养物质在水中传播的默认路径，但速度慢得令人痛苦。氧气仅仅传播1毫米就可能需要长达四分钟。这就是纤毛产生的快速流动如此重要的原因：因为自然流动的水在珊瑚表面附近减速，而珊瑚消耗氧气的速度超过了扩散供应的速度。

这是一个足以供应充足氧气的系统，尽管纤毛本身也消耗能量。但有一个缺点：随着温度升高，氧气含量下降。这时珊瑚就陷入了困境。

水下过度换气

科学家对珊瑚在水温过高时发生的一件事有着明确的理解：白化。随着水温上升，珊瑚的共生藻类受到胁迫，释放出大量对珊瑚有毒的分子。为了保护自己，珊瑚将藻类排出体外——而这些藻类是其食物、能量和氧气的主要来源——随后珊瑚很快失去颜色。这是一个缓慢的死亡过程，随着热浪席卷全球珊瑚礁，这一现象越来越常见。

但有时，同一片珊瑚礁上的某些珊瑚白化而另一些则不会，还有些情况下，处于热胁迫下的珊瑚在没有排出藻类的情况下就死亡了。

一个由微生物学家、工程师和生理学家组成的国际团队迫切希望了解高温如何影响纤毛，以及这是否能解释不同类型的珊瑚死亡。

图片提供：塞萨尔·帕切雷斯

“我们目前生活在一个极端情景频发的世界中，”新研究的合著者、哥本哈根大学研究流体动力学的海洋生物学家塞萨尔·帕切雷斯说。随着海洋热浪变得更加频繁，以及一个特别强烈的厄尔尼诺年可能于2026年底催化第五次全球白化事件，“珊瑚可能在短短几个小时内经历数摄氏度的温度上升，”帕切雷斯说。

为了探究高温对纤毛的影响，该团队进行了一系列24小时的实验。他们让人工饲养的石珊瑚——黄癣蜂巢珊瑚——逐步暴露于最高达39摄氏度（超过华氏102度）的水温中——这是一个极端情景，但确实可能发生。他们保持水箱黑暗，以便更好地观察纤毛在藻类不产生氧气时如何输送氧气。

研究人员每小时用高速摄像机记录微小的纤毛，捕捉它们在越来越热的水中摆动的频率。团队还使用了一种名为SensPIV的技术来追踪氧气流动。荧光且对氧气敏感的纳米颗粒“示踪”了水的漩涡，生成了氧气浓度与纤毛漩涡之间对应关系的清晰图谱。

可视化氧气的运动是团队发现的关键。在较温暖的水中，珊瑚消耗能量的速度更快，这增加了它们对氧气的需求——促使纤毛跳得更快。但周围水体中可用的溶解氧有限，随着温度攀升，纤毛开始将缺氧的水体疯狂地送往珊瑚。“珊瑚的氧气需求增长速度超过了水体漩涡加剧的速度，”合著者、哥本哈根大学海洋微生物学家米夏埃尔·屈尔说。

当水温接近37摄氏度（人体温度）时，纤毛开始减速。超过39摄氏度后，它们完全停止摆动，珊瑚死亡。这些是他们在2026年5月发表于《科学》杂志的发现。

图片提供：塞萨尔·帕切雷斯

帕切雷斯提醒不要将这些温度上限解读为统一阈值；每种珊瑚都适应了自己日常温度波动的范围。即便如此，气候变化已开始将许多珊瑚推向各自的极限，在佛罗里达等地，表层水温创纪录地接近38摄氏度。

纤毛在较热水中为何摆动更快仍然是个谜。夏皮罗说，也许海水的黏度——随温度升高而降低，使水变得更稀薄——影响了纤毛的运动。珊瑚没有中枢神经系统和大脑，但确实拥有神经元——位于所谓的神经网中——用于处理感觉信息。也许珊瑚感知到了高温或缺氧，然后某种生物机制触发了更快的摆动。“这是物理学、生物学、工程学交织在一起，这正是它真正有趣的原因，”他说。

珊瑚虫之谜

科学家目前在研究纤毛的生理特性以及整个边界层。“它比我们想象的要复杂得多，”夏皮罗说。

在帕切雷斯和屈尔于2026年5月合著的另一篇论文中，他们发现纤毛的漩涡类似于开瓶器形状。这种湍流将不需要的颗粒推离珊瑚表面，同时将营养物质导向珊瑚虫的口部。

图片提供：塞萨尔·帕切雷斯

他们发现，每个珊瑚虫上的纤毛以六边形单元排列，使纤毛运动保持流线型，这有助于解释纤毛如何协调运动以产生可预测的漩涡。“这表明珊瑚骨骼结构和活体组织在功能上是整合在一起的，”帕切雷斯说。

他说，综合来看，这些研究重新诠释了此前被忽视的纤毛运动如何赋予珊瑚一定的稳定性，并帮助它们缓冲环境变化的影响。

纤毛与白化之间的关系仍不明确，未参与这些研究的阿尔德迪斯说。但在不使用高温的条件下测试纤毛在白化过程中的表现——例如使用红光，红光也能触发白化——将有助于回答这个问题。

追赶进程

科学家从2014年的研究中已知纤毛在水流较低时帮助珊瑚自我通风，阿卜杜拉国王科技大学海洋生物学家大卫·萨格特说，他未参与这项研究。“但在那之前，我们一直专注于分子和代谢机制”来理解珊瑚如何进化为应对低氧条件，他说。“我们没有真正意识到有这些行为-生理机制在发挥作用。”

对萨格特来说，这项研究提出了一个关键问题：这对珊瑚将如何应对未来的气候意味着什么？

有时，同一片珊瑚礁上的珊瑚不会均匀白化，有些个体死亡而邻近的个体存活。在萨格特的同事塔德·特拉斯科特领导的新研究中，海洋生物学家发现这些斑块状的白化模式与水流减少的区域相关——这些区域因此获得的氧气更少。

接下来，屈尔和帕切雷斯的团队希望在不同条件下测试珊瑚——尤其是在正常的光暗循环下——并更好地理解驱动纤毛摆动的机制。是激活其运动的分子过程？还是较暖海水的物理学效应？两者兼而有之，还是其他什么？

萨格特说，直到过去十年，科学家才意识到脱氧在珊瑚健康中的作用。在2000年代初，海洋酸化被认为是珊瑚面临的首要问题。事后看来，脱氧是一个更大的问题，他说。新研究表明，脱氧不仅仅是白化，而且是气候变暖对珊瑚构成的致命威胁。

“我们在拼命追赶，”萨格特说。“我们迅速收集的大量信息正表明这对珊瑚来说是多么严重的问题——严重到我们开始真正重新审视关于其他环境因素（如温度和光照）的长期范式，而事实上，氧气可能一直是那个确凿的元凶。”

英文来源：

Corals Spin Tiny Vortices to Get Oxygen, but Not if It’s Too Hot
Introduction
At first glance, corals present as little more than colorful rocks — piles of lobes, stalagmites, and branches poking out from the seafloor.
They are anything but. Corals are complex creatures that form enduring colonies, and just like other animals they need oxygen to live. Across the living surface of coral, a frantic dance of survival takes place, invisible to our eyes and unknown to science before 2014. The tiny dancers are hairlike cilia, and new research into these microscopic structures is revealing just how active corals are in determining their own fate.
Corals aren’t fortunate enough to have a consistent supply of oxygen, and they can’t change location to seek it out. During the day, the tiny polyps that make up a coral colony get plenty of oxygen from the symbiotic algae that photosynthesize within their tissues. But at night that process stops, and a coral polyp’s only source of oxygen is the water around it. Then it’s do or die for the cilia. Using mechanisms scientists are still trying to understand, the cilia wave around to generate fast-moving vortices of water that circulate oxygen to the coral’s outer tissues, in addition to helping keep the colonies free of sediment.
A study published in Science in May 2026 provides new insight into how organisms with no brain or musculoskeletal system can generate and regulate this process — and what happens when the water around them warms up. Warmer water naturally carries less oxygen, which prompts corals to move their cilia faster and faster, as if gasping for breath. Above a certain temperature, the system starts to work against itself; the furious beating of cilia uses up any oxygen the coral’s tissues can absorb, and then the polyps can suffocate in the less oxygenated water. Biophysicists, marine biologists, mathematicians, and modelers are now collaborating to better understand the physiological and hydrodynamic forces at work, and how they correlate with bleaching patterns, coral disease, and mass die-offs.
This dynamic picture is somewhat new to scientists, who have long used corals’ symbiotic algal partners as indicators of their health. Cilia may serve as a more direct signal, said Rachel Alderdice, a marine biologist who studies coral stress biomarkers and genomics at the University of Konstanz in Germany and was not involved in the research. “It’s these finer details that could help us understand why some corals bleach and others don’t, [even when] they sit right beside each other.”
Swirling To Survive
Every coral colony is cushioned by a thin boundary layer of water whose movement is slowed by friction at the coral’s surface. Researchers assumed that corals were passive with respect to the slow-moving boundary layer, simply relying on natural diffusion through it to provide nutrients and oxygen.
National Marine Sanctuaries
Then, in 2014, a team from the Massachusetts Institute of Technology and the Weizmann Institute of Science published a groundbreaking study showing that coral cilia interact with the boundary layer by rapidly whipping about to generate swirls of fresh, oxygenated seawater. Until a decade ago, scientists thought of these cilia merely as brooms that move mucus and sweep away waste particles and other debris. The research not only modeled the tiny vortices created by the cilia for the first time, but also revealed the cilia’s importance for survival and metabolism.
At first, the microbiologist and environmental engineer Orr Shapiro, who led the 2014 work at MIT as a postdoctoral fellow, was interested in how microbes that infect corals and cause disease follow concentration gradients, a process called chemotaxis. Under the microscope, he noticed something weird: In the boundary layer, particles were swirling around and mixing together — not at all like the passive diffusion he had been expecting.
“That was to me, and I think later on to the entire field, sort of a paradigm shift,” said Shapiro, now a researcher at the Volcani Institute in Israel. It became clear that the boundary layer wasn’t static, but rather a dynamic zone, and one where cilia were creating their own turbulence. The realization inspired Shapiro’s team to go off on a tangent, mapping the flow of oxygen to coral tissues via cilia. “It really transformed how we understand this [micro]environment, because suddenly the diffusion is no longer really important,” Shapiro said.
Diffusion is the default route for nutrients traveling through water, but it’s painfully slow. It can take as long as four minutes for oxygen to travel just 1 millimeter. That’s why the fast-moving flows created by cilia are so important: because naturally flowing water slows down near the coral’s surface, and corals consume oxygen faster than diffusion can supply it.
It is a system that delivers enough oxygen, despite the cilia’s energy consumption. But there’s a downside: Oxygen dwindles as temperature climbs. That’s when corals run into trouble.
Hyperventilating Under Water
Scientists have a clear understanding of one thing that happens to corals when water gets too hot: bleaching. As water temperatures rise, a coral’s symbiotic algae become stressed and release molecules that are toxic to the coral in large quantities. To protect itself, the coral expels its own algae — a primary food, energy, and oxygen source — and soon loses its color. It’s a slow death and an increasingly common occurrence as heat waves sweep across the world’s reefs.
But sometimes, some corals on a reef bleach while others don’t, and in other cases corals under heat stress die without expelling their algae.
An international team of microbiologists, engineers, and physiologists was eager to understand how heat affects cilia, and whether this could explain different types of coral death.
Courtesy of Cesar Pacherres
“We’re living in a world right now of extreme scenarios,” said Cesar Pacherres, a co-author of the new study and a marine biologist at the University of Copenhagen who studies fluid dynamics. As marine heat waves become more common, and as a particularly strong El Niño year threatens to catalyze a fifth global bleaching event in late 2026, “corals can experience an increase in temperature of several degrees in a time frame of a few hours,” Pacherres said.
To explore heat’s impact on cilia, the team ran a series of 24-hour experiments. They exposed aquarium-raised stony coral called Porites lutea to incrementally higher water temperatures up to 39 degrees Celsius (more than 102 degrees Fahrenheit) — an extreme scenario, but one that could occur. They kept the tanks dark to better observe how cilia transport oxygen when algae aren’t producing any.
Every hour, the researchers recorded the microscopic cilia with a high-speed camera to capture how frequently they moved as they were exposed to warmer and warmer water. The team also used a technology called SensPIV to track oxygen flow. Fluorescent, oxygen-reactive nanoparticles “traced” the water swirls, creating a vivid map of how oxygen concentrations corresponded to the cilia’s vortices.
Visualizing the movement of oxygen was key to the team’s findings. In warmer water, corals burned energy faster, which increased their demand for oxygen — prompting the cilia to dance faster. But there’s only so much dissolved oxygen available in the surrounding water, and as temperatures climbed, the cilia started to send oxygen-deficient water toward the coral in their frenzy. “The oxygen demand of the coral increased faster than the increased swirling of the water,” said co-author Michael Kühl, a marine microbiologist at the University of Copenhagen.
When the water approached 37 degrees Celsius (the temperature of the human body), the cilia started to slow down. Past 39 degrees Celsius, they shut down altogether, and the coral died. These were the findings they reported in Science in May 2026.
Courtesy of Cesar Pacherres
Pacherres cautioned against interpreting these temperature limits as a standard threshold; each species of coral is adapted to its own range of daily temperature fluctuations. Even so, climate change has started to push many corals toward their respective limits, with record-high surface water temperatures nearing 38 degrees Celsius in places such as Florida.
Why the cilia move faster in hotter water remains a mystery. Perhaps seawater’s viscosity — which decreases as temperature increases, making the water thinner —affects ciliary movements, Shapiro said. Corals lack a central nervous system and brain, but they do have neurons — inside what’s called a nerve net — to process sensory information. Perhaps the coral senses heat or lack of oxygen, and some biological mechanism then triggers the faster beating. “It’s physics, biology, engineering, all mixed up together, which is what makes it really interesting,” he said.
A Polyp Puzzle
Scientists are now investigating cilia physiology and the boundary layer as a whole. “It’s much more complex than we thought,” Shapiro said.
In another paper co-authored by Pacherres and Kühl in May 2026, they found that cilia’s vortices resemble corkscrews. The turbulence pushes unwanted particles away from the coral’s surface while redirecting nutrients toward polyps’ mouths.
Courtesy of Cesar Pacherres
The cilia on each polyp, they found, are arranged in hexagonal units that keep ciliary movement streamlined, which helps explain how cilia can coordinate their movement to produce predictable swirls. “It demonstrates that coral skeletal architecture and living tissue are functionally integrated,” Pacherres said.
Combined, the studies recontextualize how ciliary movement, previously overlooked, gives corals some stability and buffers them against environmental change, he said.
The relationship between cilia and bleaching remains ambiguous, said Alderdice, who was not involved in the studies. But testing cilia under bleaching conditions without heat — by using red light, for example, which can also trigger bleaching — would help answer this question.
Playing Catch-Up
Scientists knew from the 2014 work that cilia help corals self-ventilate when water flow is low, said David Suggett, a marine biologist at King Abdullah University of Science and Technology who wasn’t involved in the research. “But until this point, we had been focusing on molecular and metabolic machinery” to understand how corals evolved to deal with low-oxygen conditions, he said. “We hadn’t really appreciated that there are these behavioral-physiological mechanisms at play.”
For Suggett, the research raises a critical question: What does this say about how corals will deal with future climates?
Sometimes, corals of a single reef don’t bleach evenly, with some individuals dying off while their neighbors persist. In new research led by Suggett’s colleague Tadd Truscott, marine biologists are finding that these patchy bleaching patterns are correlated with areas of reduced water flow — areas therefore receiving less oxygen.
Next, Kühl and Pacherres’ team wants to test corals under different conditions — especially under normal light-dark cycles — and to better understand the mechanism driving ciliary beating. Is it a molecular process that activates their movement? The physics of warmer seawater? A bit of both, or something else?
It’s only in the past decade that scientists have realized the role of deoxygenation in coral health, Suggett said. Ocean acidification took center stage as the primary concern for corals in the early 2000s. In hindsight, deoxygenation was a much bigger issue, he said. The new research suggests that deoxygenation, not just bleaching, is a fatal threat to corals resulting from a hotter climate.
“We’re playing massive catch-up,” Suggett said. “The amount of information we’re gathering quickly is demonstrating just what a problem for corals it is — so much so that we’re starting to really revisit long-standing paradigms of the role of other environmental factors, like temperature and light, where in fact, it could be oxygen that’s been the smoking gun all along.”