The East Pacific Ridge is a chain of volcanoes on the floor of the southeastern Pacific Ocean that runs roughly parallel to the west coast of South America.
The main part of the ridge generally lies about 3,200 km offshore, with its northernmost spurs extending to the mouth of the Gulf of California, where it merges with the transform zone of the Pacific-North American plate boundary.
From its southernmost point, it continues west-southwest as the Pacific-Antarctic Ridge, approaching Antarctica south of New Zealand.
The surface of the East Pacific Ridge is essentially smooth and flat, dropping steeply on the sides, it is highly fissured by faults, which usually occur at intervals of about 320 km.
Associated with volcanic activity are a number of hydrothermal vents, upwellings of heated seawater that often contain a variety of sulphide minerals. These vents support organisms that exist through chemosynthesis of sulphur-fixing bacteria.
Very few people will ever encounter the colonial tubeworm Oasisia sp. in the wild, i.e. in the depths of the Pacific Ocean.
Only with the help of special deep-sea submersibles is a glimpse into this biotope of black smokers and white smokers even possible, and the question arises as to how the filigree-looking tubeworms are able to live and feed at such depths and in such close proximity to the hydrothermal vents at the bottom of the deep sea.
Healthy coral reefs are among the most species-rich biotopes and thermal smokers are the most densely populated habitats in the deep sea!
An unbelievably large number of unknown species of animals can be found here, such as the colonial tubeworm Oasisia alvinae and Tevnia jerichonana, a wide variety of shrimp and crab species, molluscs,
actinia and fish.
On the diet of the worms:
Many corals have entered into a symbiosis with energy-providing dinoflagellates (zooxanthellae), and Oasisia sp. has also formed such a symbiosis with bacteria.
The symbiotic sulphur bacteria carry out an oxidation of sulphide with oxygen (chemosynthesis) to gain energy, which is passed on to the worm host.
The endosymbionts have other tasks that the mouth- and gutless worm cannot do, such as disposing of waste, the worm is only left with the task of supplying its symbionts with sufficient oxygen and sulphide.
It is interesting to note that juvenile worms do not yet have endosymbiotic bacteria, on the contrary, the young worms eat the bacteria in the first period of their life, later the bacteria penetrate the worm's tissue via the body surface and settle there.