珊瑚是複雜的群體生物，需要氧氣才能存活。白天，共生藻類通過光合作用為珊瑚提供充足的氧氣，但夜間這一過程停止，珊瑚只能依賴周圍海水中的溶解氧。珊瑚表面的微小纖毛會快速擺動，產生渦旋將含氧海水輸送至組織表層，這一機制直到2014年才被科學家發現，徹底改變了人們對珊瑚邊界層的認知——它並非被動擴散區域，而是由纖毛主動驅動的動態環境。

2026年5月發表於《科學》期刊的一項研究揭示了水溫升高對珊瑚纖毛的影響。研究團隊將石珊瑚暴露於逐步升高的水溫中（最高達39°C），並利用螢光奈米粒子追蹤氧氣流動。結果顯示，水溫升高時珊瑚代謝加快、氧氣需求增加，纖毛隨之加速擺動；然而當溫度接近37°C時纖毛開始減速，超過39°C後完全停止運作，珊瑚隨即死亡。這如同珊瑚在水下「過度換氣」——纖毛愈拼命攪動，反而將缺氧的水推向珊瑚表面。

這項研究為理解珊瑚在氣候變遷下的命運提供了新視角。科學家過去主要以共生藻類的白化現象作為珊瑚健康指標，但纖毛可能是更直接的信號，有助於解釋為何同一礁體上有些珊瑚白化而鄰近個體卻安然無恙。研究者還發現纖毛排列呈六角形單元、產生螺旋狀渦旋，顯示珊瑚骨骼結構與活體組織具有功能整合性。目前學界正重新審視脫氧對珊瑚的致命威脅，認為氧氣匱乏可能才是珊瑚大規模死亡的根本原因。

Corals are complex colonial organisms that depend on oxygen for survival. During the day, symbiotic algae supply ample oxygen through photosynthesis, but at night corals must rely solely on dissolved oxygen in surrounding seawater. Hairlike cilia on the coral surface beat rapidly to generate vortices that deliver oxygenated water to the tissue — a mechanism discovered only in 2014 that fundamentally shifted scientists' understanding of the coral boundary layer from a passive diffusion zone to an actively driven, dynamic microenvironment.

A May 2026 study published in Science investigated how rising water temperatures affect coral cilia. Researchers exposed stony coral to incrementally higher temperatures up to 39°C while tracking oxygen flow with fluorescent nanoparticles. As temperatures rose, corals' metabolic demand for oxygen increased and cilia beat faster in response. However, near 37°C the cilia began to slow, and beyond 39°C they stopped entirely, leading to coral death. In essence, the corals were hyperventilating underwater — their frantic ciliary beating ultimately drew oxygen-depleted water toward the tissue rather than replenishing it.

The findings offer a new lens for understanding coral fate under climate change. Scientists have traditionally relied on algal bleaching as the primary health indicator, but cilia may provide a more direct signal — potentially explaining why neighboring corals on the same reef respond differently to heat stress. Additional research revealed that cilia are arranged in hexagonal units producing corkscrew-shaped vortices, demonstrating functional integration between coral skeletal architecture and living tissue. The scientific community is now reassessing deoxygenation as a critical and possibly primary driver of coral mortality, suggesting that oxygen deprivation — not bleaching alone — may be the smoking gun behind mass die-offs in a warming ocean.