They weren’t snakes, of course, but nematodes, also known as roundworms—and, it turns out, they’re the most common ...

The volcano's summit features a caldera—formed by volcanic eruptions—and supports vibrant hydrothermal vent ecosystems populated by microbes, tube worms, crabs, fish, octopuses and more.

Entire communities of giant tube worms and blind crabs were found thriving in these sulfurous depths. Since then, similar chemosynthetic life has been found around cold seeps, mud volcanoes ...