The superheated seawater ejected from the vents is black because of the chemicals and metals dissolved from the surrounding lava. German came to prominence as a young researcher when he suggested that black smokers did not just appear in the Pacific. They could appear at any underwater site of volcanic activity. Other people said it was just muck off the sea floor, that ocean currents were churning up the sea floor. German was later proved correct.
Black smokers are just about the most hostile places on Earth.
Their immediate vicinity boasts temperatures of between 100C and 200C and the pressures at the bottom of the sea are 200 times those found on land. To cap it all, the black plumes contain all sorts of toxic compounds, such as mercury and arsenic. Yet numerous underwater missions have shown that life thrives there. After all, we wouldn't say that people in Bangladesh are adapted to cope with floods and storms. In the same way, these life forms might be running uphill very fast.