Everything about Black Smokers totally explained
A
black smoker or sea vent, is a type of
hydrothermal vent found on the
ocean floor. They are formed in fields hundreds of meters wide when
superheated water from below
Earth's
crust comes through the ocean floor. This water is rich in dissolved
minerals from the crust, most notably
sulfides. When it comes in contact with cold ocean water, many minerals precipitate, forming a black chimney-like structure around each vent. The metal sulfides that are deposited can become
massive sulfide ore deposits in time.
Black smokers were discovered in 1977 on the
East Pacific Rise by scientists from
Scripps Institution of Oceanography. They were observed using a small submersible vehicle called
Alvin. Now black smokers are known to exist in the
Atlantic and
Pacific Oceans, at an average depth of 2100
meters. The temperature of the water at the vent can reach 400
°C, but doesn't usually boil at the seafloor because the water pressure at that depth exceeds the
vapor pressure of the aqueous
solution. The water is also extremely
acidic, often having a
pH value as low as 2.8 — approximately that of
vinegar. Each year 1.4 × 10
14 kg (370 trillion gallons) of water is passed through black smokers.
Ecosystems
Although life is very sparse at these depths, black smokers are the center of entire
ecosystems. Sunlight is nonexistent, so many organisms — such as
archaea and
extremophiles — convert the heat,
methane, and
sulfur compounds provided by black smokers into energy through a process called
chemosynthesis. More complex life forms like
clams and
tubeworms feed on these organisms. The organisms at the base of the
food chain also deposit minerals into the base of the black smoker, therefore completing the
life cycle.
A species of phototrophic bacterium has been found living near a black smoker off the coast of
Mexico at a depth of 2500 m. No sunlight penetrates that far into the waters. Instead, the bacteria, part of the
Chlorobiaceae family, use the faint glow from the black smoker for
photosynthesis. This is the first organism discovered in nature to use a light other than sunlight for photosynthesis (Beatty,
et al., 2005).
New and unusual species are constantly being discovered in the neighborhood of black smokers: for instance, the
Pompeii worm in the 1980s, and a
scaly-foot gastropod in 2001 during an expedition to
Indian Ocean's Kairei hydrothermal vent field. The latter uses iron sulfides (
pyrite and greigite) for the structure of its dermal
sclerites (hardened body parts), instead of
calcium carbonate. The extreme pressure of 2500 m of water (approximately 25
megapascals or 246.73
atmosphere) is thought to play a role in stabilizing iron sulfide for biological purposes. This armor plating probably serves as a defense against the venomous
radula (teeth) of
predatory
snails in that community. This snail, which is unique in its kind, hasn't yet been named.
Further Information
Get more info on 'Black Smokers'.
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