This part of the museum, unlike most other parts, is designed not taxonomically, but “ecologically”, so the main object of this part is not a particular taxonomic group but a community of diverse animals that constitute a very specific ecosystem, “submerged” into the depth of the ocean. Hydrothermal ecosystem is the only ecosystem of its own kind on the Earth caused to the existence by specific planetary-scale processes taking place in the bowels of the Earth.
The vents in question are
formed in the spreading zones, i.e. in the areas of slow (from 1-2 to 18-
The ocean water penetrates into the crust by cracks of the young bark to become oversaturated with minerals and heated and then returns to the ocean through the hydrothermal vents. The most hot vents with black or dark water similar superficially to the smoke are called black smokers, and more cold vents of whitish water are called white smokers.
The vents are effusions of warm (up to 30-40° C) or very hot (up to 370-400° C) water, the so-called fluid of oversaturated compounds of sulfur, iron, manganese, and some other chemical elements, and a myriad of bacteria living at the temperatures up to 110° C.
The water near these specific volcanoes is almost fresh, very acidic and rich in hydrogen sulfide. The “fireplace chimneys” of these smokers are growing onto this “liquid ore” with fantastic speed, sometimes several meters per month.
Finding of hydrothermal vents
on the bottom of the
A fantastic world was opened in which ocean water in contact with the hot interior of the Earth gave rise to a very rich life. This was true oases among desert landscapes of the deep seas.
Within the first 20 years (1977-1997) of study of quite rich hydrothermal fauna, discovered were more than 450 species of animals, 97% of which appeared to be new to science. With discovery of new vents and more detailed study of already known ones, more and more new kinds of organisms are constantly being discovered.
Biomass of the hydrothermal
animal communities is
Stunning impression was produced
by first photographs taken by submarines, which managed to capture the thickets
of white tubes up to
The front end of the worm's body bears a complex tentacular apparatus. The central tentacles are richly supplied with blood saturated with respiratory pigment hemoglobin, therefore they are bright red in color. Gas exchange is carried out through them. One of the characteristic features of Vestimentifera is a spongy tissue that occupies most of their body. This tissue, called trophosome, serves as the seat of the symbiotic bacteria that can hold more than 30% of its volume and supply their hosts with the nutrients.
Symbionts are capable of utilizing hydrogen sulfide effused by smokers in great amount. Process for producing organic compounds by means of oxidation of inorganic compounds is called chemosynthesis, which unlike photosynthesis does not require any light. They provide the oxidation of sulphides, which are toxic to all multicellulate animals. So bacteria are a key link in the entire food pyramid in the ecosystems of hydrothermal vents.
There are several rather large
(up to 18-
The outer walls of vent craters,
where the water temperature reaches about 100° C, is covered by a continuous “carpet”
formed by colonial polychaete worms of the genera Alvinella and Paralvinella.
These worms live in thin leathery tubes produced by themselves, but use to come
out of the tubes from time to time and float around, moving away to a distance
Numerous shrimps of the genus Rimicaris living in enormous clusters directly on the vents also feed upon bacteria settling on the shrimps’ gills. The latter totally devoid of eyes, but have a special sensory organ located on their back. This organ allows to shrimps to keep themselves within a narrow range between zone of very hot and cold waters.
There are specific predators feeding on other hydrothermal inhabitatns; these are blind white crabs of the genera Bythograea and Cyanograea. They are joined by several widespread predators of the oceanic depths, such as king crabs (Neolithodes, Paralomis) and some fish.
Discovery of hydrothermal communities showed that the Sun is, though the main, but not the only source of energy for life on Earth.
Role of hemobiosis in the life