Dragon Hole: World's deepest underwater cave has no oxygen below 100m
Dragon Hole, once considered the planet's deepest underwater cave in the South China Sea, drops to a staggering 301 meters—and below about 100 meters, oxygen levels drop to zero.
That means fish and most complex life can't survive there, but something else is thriving.
Microbes rule where nothing else can
Even without oxygen, Dragon Hole is buzzing with microbial life.
Two main "no-oxygen" zones are packed with sulfur-eating bacteria—think of them as tiny survivors built for extremes.
Deeper down, other bacteria handle rising hydrogen sulfide levels, showing off nature's wild adaptability.
Why does this matter?
Scientists found hundreds of new bacteria and deep-sea viruses here—some totally new to science.
Studying these tough microbes could help us understand how life might exist on early Earth or even on other planets.
Plus, it's a reminder that some of our planet's coolest mysteries are still hidden underwater.