Deep sea vents are also
known as hydrothermal vents, deepwater seeps, deep sea springs
or hydro-thermal vents. They are in the planet’s surface and are great submarine
geysers generated because of the geothermal energy. There are hydrothermal vents
in several zones of the planet; nevertheless, the first submarine hydrothermal vents
that were studied and probably the most famous are to the east of the Galapagos
Islands.
The hydrothermal vents are usually formed along the Mid Ocean ridges in locations
where two tectonic plates are diverging; this circumstance creates a great geothermal
energy that generates the hydrothermal vents, which are mainly sea water which is
expelled with great pressure and high temperature, because of the magma that heated
the water. The hydrothermal vents situated near Galápagos were formed because of
the split of the Farallon plate into two separate plates, the Cocos Plate at north and the Nazca Plate at the south. They are commonly more than 2438 meters (8000
feet) below the surface of the ocean.
The hydrothermal vents are flows of emerged water which are mixed quickly with several
minerals like manganese, copper, zinc, iron, mineral anhydrite, and sulfides. The
water emerges at temperatures that can reach 400ºC .The hydrothermal vents; shape
some times roughly cylindrical chimney structures composed by mineral particles
from the thermal water flow. These chimneys reach heights of until 60 meters. Some
of these chimneys expelled water of dark color;
therefore they are called “black
smokers”.
The most impressive about these geothermal systems is the life that they sustain.
Even before the discovery of these hydrothermal vents, scientists thought that the
existence of life to this deep, temperature and without sunlight was not possible.
Nevertheless, this fantastic discovery demonstrated that life can be adapted and
thrive in almost any environment; the hydrothermal vent’s discovery changed forever
the vision we had about the biology in the Earth.
Most organisms in the planet get its energy from the sunlight; plant cells use the
sun’s energy to generate the organic compounds (carbohydrates, oxygen, etc.) and
the energy that they need to survive, other organisms of upper levels in the food
chain, exploit also the solar energy when they eat photosynthetic organisms or even
when they respire. Scientists knew the existence of several organisms in the deep
sea; but they thought that these organisms are sustained by a nutrients rain from
the upper levels of the ocean; that is to say, they depended also of the sun’s energy
to survive. However, the organisms that inhabit the zone around the hydrothermal
vents depend only of the resources generated by the hydrothermal chimneys. The first
link in the food chain of this system is an amazing chemosynthetic bacterium, which
use sulfur compounds like hydrogen sulfide and the geothermal energy to produce
energy and organic material. Most organisms of the ecosystem use these bacteria
as food; that means, chemosynthetic bacterium is the base of the life in the hydrothermal
vents.
Hydrothermal fluid are expelled of the vents containing hydrogen sulfide, the chemosynthetic
bacterium around the vents take hydrogen sulfide, oxygen and carbon dioxide from
the water. Later, bacterium use these compounds to get energy by braking down the
hydrogen sulfide; with the energy generated and oxygen, the microbes convert carbon
dioxide into sugars; finally, bacterium release sulfur and water. This process similar
to the photosynthesis, allow to survive the bacterium and the rest of ecosystem’s
organisms of the hydrothermal vents.
This marvelous unique type of ecosystem sustains a great
variety of organisms such
as pogonophorans, gastropods, annelids, bivalve, amongst other. All they are perfectly
adapted to survive in the extreme environmental condition of the hydrothermal vents;
a great example of this fact is the great number of large communities of tube worms
that inhabit this ecosystem; these worms absorb nutrients directly trough their
tissues in a symbiotic relationship with the chemosynthetic bacterium. There are
also blind crabs (they don’t need to see because there is not light), pink ventfish,
sea cucumbers, sponges, brittle stars, around 48 mollusk species and many other
unique species.
History
In 1977 a chemosynthetic ecosystem was discovered surrounded a set of submarine
hydrothermal vents along the Galapagos Rift in the East Pacific Rise. Bu,t only
two years later in 1979 a group of biologists came back to the zone to study the
hydrothermal vent communities. Scientists used to see the hydrothermal vents, an
ONR research submersible called ALVIN. Thanks to this research, this same year,
Peter Lonsdale published a work about the hydrothermal vent life, which showed for
first time to the world the existence of this wonderful new universe.
Life Around Hydrothermal Vents
The discovery of this new ecosystem revolutionized the biology, because it showed
that the life in the Earth could exist in extreme environments and on unexpected
ways. Since 1979, scientists have discovered around 300 species of life living around
the hydrothermal vents. There raised questions that never entered our minds before,
such as what special features do organisms have to live at hydrothermal vents? Why
do different kinds of animals live different vent sites? How the animals migrate
to other vent site? and many other questions.
Since 1979, several other hydrothermal vents have been discovered and studied, such
as the Kermadec Arc in New Zealand that is still explored by the company Neptune
Resources NL.
One of the vents discovered recently is the Medusa hydrothermal, which
is located in the Pacific Ocean offshore of Costa Rica, this deep sea vent was discovered
in 2007. Wherever, it looks along the ridge, it finds hydrothermal vents and the
vents in different regions of the ocean host very different animals.
Nevertheless, since the discovery of the hydrothermal vents a new dilemma was born;
since, these places are not only a wonderful ecosystem; they are also a new source
of rich for the mining.
The great quantities of minerals that are in the hydrothermal vents could be exploited
via deposition of seafloor massive sulfide deposits, as is done in Mt Isa in Queensland
Australia. Several mineral explorations companies have showed its interest for the
extraction of minerals directly from the hydrothermal fields. This kind of underwater
mining involves the construction of new infrastructures, which could harm seriously the delicate
ecosystem around the hydrothermal vents. Therefore; more studies must
be done before allowing the mining activities in these unique places; since, if
the hydrothermal vents are destroyed, we will destroy also a whole universe of life,
which until recently we did not know and about which we know still very little.
The preservation of the deep sea vents and the ecosystems linked to them is a responsibility
of entire humanity. The major challenge of the future is to design more efficient
ways of exploring the remaining 90 percent of the ocean ridge that we have not still
discovered.