Smoke in the Water

A black smoker chimney billows from a hydrothermal vent site called “Snake Pit” on the Mid-Atlantic Ridge. It was photographed by scientists Holger Jannasch and Cindy Van Dover diving in the WHOI-operated human-occupied submersible Alvin in 1993. Black smokers are so named because they appear to spew dark smoke from tall, rocky chimneys. The “smoke” is actually made of dark, fine-grained, mineral-rich particles suspended in plumes of superheated fluids. The “chimneys” are made of minerals that have precipitated from scalding vent waters as they met cold seawater and solidified into lengthening structures. Black smokers were first discovered 40 years ago. (Photo courtesy of Woods Hole Oceanographic Institution Archives)