Biologists have observed a variety of smaller crustaceans around vents, including miniature lobsters called galatheids, and amphipods resembling sand fleas. They have also seen snail-like limpets the size of BBs, sea anemones, snakelike fish with bulging eyes, and even octopuses. While octopuses are at the upper end of the vent's food chain, bacteria are at the bottom. They are the first organisms to colonize newly formed vents, arriving in a snowlike flurry and then settling to form white mats or tendrils attached to the ocean floor. Bacteria have been found living beneath the ocean's floor, and it seems likely that they emerge from below when the conditions are right.
Vent bacteria can withstand higher temperatures than any other organism.
That makes them attractive to researchers who are developing heat-stable enzymes for genetic engineering, and culturing bacteria designed to break down toxic waste. However, the intense heat is limited to a small area. Within less than an inch of the vent opening, the water temperature drops to 2 C, the ambient temperature of deep seawater. Most of the creatures that congregate around vents live at temperatures just above freezing. Thus chemicals are the key to vent life, not heat.