how hydrothermal vents form
The process begins when water seeps down through cracks into the Earth's crust, usually in volcanically active regions of the sea floor like the mid-ocean ridge. The magma within the Earth's layers cause the water to become superheated, at which point the water rises up out of the ocean floor. On the way, it picks up dissolved minerals, and deposits these upon mixing with the cooler seawater above. The towering chimney structures form as a result of these minerals solidifying.
There are a number of varieties of hydrothermal vents, each one characterised by its specific mineral content. Black smokers emit hotter, darker plumes, building chimneys over 180 feet tall (50 metres). They have high levels of sulphides that precipitate out of the vent fluid to form the black smoke.
Another vent variety is the white smoker, which has a mineral content of barium, calcium and silicon.
To conclude, deep sea vents are able to support a unique ecosystem and a community of highly-specialised and unique organisms in the deep. The islands of diversity and productivity that they form in the otherwise lifeless depths are sites of outstanding scientific interest, providing a relatively new insight into how life evolves, forms and adapts to a harsh environment. But with these vents only having been discovered in the 1970s, there remains a wealth of secrets in the deep sea, yet to be discovered.