is a field of hydrothermal vents
in the mid-Atlantic ocean
that differ significantly from the black smoker
vents found in the late 1970s. The vents were discovered in December 2000 during a National Science Foundation
expedition to the mid-Atlantic. A second expedition mounted in 2003 used DSV Alvin
to explore the vents. The details of the chemistry and biology of the Lost City hydrothermal field were published in March 2005.
The vents are located on the seafloor mountain Atlantis Massif
, where reactions between seawater and upper mantle peridotite
- and hydrogen
-rich fluids that are highly alkaline
9 to 11) , with temperatures ranging from <40° to 90°C. There is a field of about 30 chimneys made of calcium carbonate
30 to 60 meters tall, with a number of smaller chimneys.
Lost City vents release methane
into the surrounding water; they do not produce significant amounts of carbon dioxide
, hydrogen sulfide
or metals, which are the major outputs of volcanic black smoker
vents. The temperature and pH of water surrounding the two types of vent is also significantly different. Strontium
, and oxygen isotope
data and radiocarbon
ages document at least 30,000 years of hydrothermal activity driven by serpentinization
reactions at Lost City, making the Lost City older than known black smoker vents by at least two orders of magnitude. Correspondingly, Lost City and black smoker vents support vastly different lifeforms.
The Lost City... Read More