PLANET EARTH Caves

The salamander（火蜥蜴，蝾螈） might not encounter food for several months, so when something does come along it can't afford to miss it. It's astonishing that these extraordinary cave dwellers manage to survive at all. But one cave is so inhospitable that one would not expect it to contain any life whatsoever. The water flowing out of the Villa Luz cave in Mexico is actually colored white with sulphuric acid（硫酸）.



Explorers entering this dangerous cave must wear respirators and carry monitors. Poisonous gases rise to fatal levels so quickly that an early warning system is essential. Bats survive by staying close to the skylights, but venturing deep into the cave is very dangerous indeed. The source of these toxic fumes（烟雾或气体，特指难闻且有害的烟雾或气体） lies several miles below.



Hydrogen sulphide（硫化氢） gas bubbles up from oil deposits in the earth's crust（地壳）. It mixes with oxygen and the water, and forms sulphuric acid. These are not the sort of conditions in which you would expect to find fish, yet these cave mollies seem to thrive despite the acid and the low levels of oxygen.