Join DIVE AND DISCOVER on a one-week expedition
to some of the Earth's most spectacular hydrothermal vents.
DIVE AND DISCOVER's first voyage takes you to the Gulf of California,
the sliver of ocean separating Baja California from mainland Mexico.
It's a place of stunning scenery where mountains rise sharply above
blue water and white beaches, where the warm waters are rich in marine
life, and where California gray whales return every winter to give
Deep beneath the blue waters lie even more stunning
biological and geological wonders. Here can be found part of
the global mid-ocean
where the Earth's crust is born. Large fractures called transform
across the seafloor. Between these faults lie deep basins where
the seafloor is spreading apart. It is within these basins where
new ocean crust emerges and scalding seawater jets out of hydrothermal
vents like smoke from a locomotive.
In 1980, researchers from the Scripps Institution
of Oceanography in La Jolla, California, sent the deep-sea robot
DeepTow down to map one of these mid-ocean ridge spreading centers-the
2,000 meter-deep Guaymas Basin. There they discovered spectacular black
Surrounding the smokers was a lush community of deep-sea organisms
ranging from tubeworms and giant clams to the tiny microorganisms
that feed off of chemicals spouting out of the vents.
Now a team of scientists led by Dr. Craig Cary
and Dr. George Luther of the University of Delaware and Dr. Anna-Louise
Reysenbach of Portland State University has returned to Guaymas
Basin. The scientists will dive to hydrothermal vents on the
seafloor on board Alvin, the Woods Hole Oceanographic Institution’s
deep-diving research submarine. There they will map the vents
and surrounding seafloor, collect minerals from the chimneys,
and analyze the chemicals spouting up from the vents. Finally
they will collect and study the fascinating organisms that depend
on these chemicals to survive.
This research will not only provide valuable information
about deep-sea vent biology and chemistry, it may provide tantalizing
clues about the origin of life on Earth.
Join Drs. Cary, Luther and Reysenbach and their
team of scientists, students and engineers on each exciting dive
into the Guaymas Basin.
The biological communities that have evolved
around hydrothermal vents thrive in conditions that are almost
unimaginable. The organisms live in total darkness. They feed
off of chemicals that are toxic to most other living things,
including people. Some of these organisms survive in water
hotter than 100°C (212°F).
Yet scientists now hypothesize that the first life
on Earth may have evolved under these hot and corrosive conditions.
Genetic analysis has shown that many of the microbes that live
around vents today are closely related to these first microbes.
Scientists diving to to vents in Guaymas Basin
will begin to test the theory that life may have originated around
hydrothermal vents or under similar conditions. They will search
for clues in the chemicals coming out of the vents and among
the microbes that live around the vents.
Pyrite the Key?
The Guaymas Basin team is focusing their attention on one mineral
in particular. This mineral is called pyrite, or fools gold.
Black smoker chimneys are made of pyrite.
Pyrite is formed when hydrogen sulfide (H2S) and
iron monosulfide (FeS) react. Both of these chemicals are present
in the hydrothermal fluid that jets out of the vents.
Here is the chemical reaction:
hydrogen sulfide (H2S) + iron monosulfide (FeS) -- -----> pyrite
(FeS2) + hydrogen gas (H2) + energy
Some scientists now propose that this chemical
reaction may have played a key role in the origin of life.
Providing Energy for Life
All organisms need energy to survive. We get energy from the food
we eat. Plants get energy from the sun. The microbes that inhabit
hydrothermal vents get their energy from chemicals in the hydrothermal
fluids. The process by which organisms harvest energy from chemicals
is called chemosynthesis.
Some scientists propose that the first microbes
may have gotten their energy from the chemical reaction between
H2S and FeS that forms pyrite. Another possibility is that the
microbes got their energy from hydrogen gas that is produced
during the pyrite reaction. Today, there are many microbes living
in high-temperature waters that use hydrogen as an energy source.
Testing the Hypothesis
The scientists on this cruise will begin to test the hypothesis
that life originated around hydrothermal vents or under similar
conditions. One of the first tests is to try and find microbes
living today that use the pyrite reaction to get energy.
- They will use an extremely sensitive chemical
sensor called a voltametric microelectrode attached to Alvin
to detect hydrogen sulfide (H2S) and iron monosulfide (FeS).
Remember that these are the chemicals that react to form pyrite.
- Using Alvin, they will collect vent
chimney samples and microbes from areas where they find high
concentrations of H2S and FeS and bring them back up to the
ship for analysis. They will identify and catalog all of the
microbes they find.
- Finally they will try to culture (grow) the
microbes in an environment where H2S and FeS are reacting to
form pyrite. Using this experimental approach, the scientists
will test whether these microbes can survive by using the energy
from the pyrite reaction.