Life at the hydrothermal vents
The floor of the deep ocean is almost devoid of life, because little food can be found there. But around hydrothermal vents, life is abundant because food is abundant. Hot, mineral-rich fluids supply nutrient chemicals. Microbes, some of which eat these chemicals, form the base of the food chain for a diverse community of organisms. These vents are the only places on Earth where the ultimate source of energy for life is not sunlight but the inorganic Earth itself.
Did life begin at deep-sea vents?
This is one theory, and it is supported by several lines of evidence. First, some of the thermophilic, or heat-loving, vent microbes are the most primitive organisms known on Earth. They include Archaea, which belong to a third domain of life and are as different from bacteria as bacteria are from all other organisms. Second, complex organic molecules, the building blocks of life, are found at the vents. Third, the deep ocean was one of the few places on the early Earth that was protected from frequent meteorite bombardments and lethal radiation.
Since hydrothermal vents were first discovered in 1977, scientists have identified over 300 animal species living at them. Ninety-five percent of these are unique to the vent environment, and thus were previously unknown. Some, like the tube worms, are not closely related to anything else. Why are vent animals so unlike those elsewhere? These creatures probably took divergent evolutionary paths in the distant past. The vent community is ancient and has evolved little over millions of years.
Tube worms absorb hydrogen sulfide and other chemicals from vent fluids to feed bacteria living in them. In return, the bacteria provide the carbon necessary for the tube worms to live.
Topic: Earth Science
Subtopic: Life in Extreme Environments
Keywords: Tube worms, Ocean bottom, Life (Biology), Life--Origin, Microorganisms, Extreme environments, Hydrothermal vent ecology, marine organisms, Marine biology
Microbes are at the base of the food chain.
Some ore deposits now exposed on land originally formed in the oceans.
Just as they form today at the mid-ocean ridges, the sulfide chimneys that were to become the ores of the Kidd Creek mine, in Ontario, Canada, were forming on the seafloor 2.7 billion years ago.