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About a mile down in the Pacific Ocean floor lie what are called hydrothermal vents. These are seafloor springs that can be found along mid ocean ridge systems. They emit a super heated hydrothermal brew that could easily put on a show to rival Yellowstone’s Old Faithful. Alongside these hydrothermal vents, however, can be found a life form that is even more intriguing. This is the tube worm. Tube worms can grow as large as three meters (eight feet tall). They are firmly anchored to the ocean floor and grow upright.
The tube worm makes an impressive sight with its white tubes and delicate red plumes, which contain blood rich in hemoglobin. The white tube-like substance which forms the tube worm’s skin is made of chitin, an extremely hardy material. The tube worm, however, has neither eyes nor mouth. Neither do they have a digestive. Scientists were, therefore, perplexed as to just how this creature of the deep ate and assimilated it’s food. The discovery of red blood flowing throughout the worm rather than a blood like fluid further deepened the mystery. Inside the flaccid sac of the tube worm’s body, scientists have found a bacterial culture composed of some ten billion bacteria for every gram of tissue. It was hypothesized and then proven that the tube worm survives by means of symbiosis. In other words the tube worm feeds the bacteria and the bacteria feed the worm.
The red plumes of the tube worm gather ingredients such as oxygen and carbon that are needed by the bacteria to manufacture food. This takes place not in the overheated areas directly alongside the super hot hydrothermal vent waters, but a little distant where the freezing seawater and vent water mix. Energy for this food making process comes from hydrogen sulphide produced by the hydrothermal vents. The process by which the bacteria convert oxygen and carbon into food by means of hydrogen sulphide is known as chemosynthesis.
In order to bind all of the chemicals that are needed by the bacteria, the blood of the Tube Worm is composed of hemoglobin molecules that are thirty times larger than the hemoglobin molecules found in humans. So the blood of the tube worm carries the needed chemicals to the bacteria who, in turn, convert them into food for the tube worm.
But since the tube worm has no mouth how do the bacteria get into it in the first place? Interestingly, scientists have discovered that, at their earliest stages of development Tube Worms do indeed have mouths as well as a digestive system. The bacteria can travel through these passages until, with the passage of time, the mouth and gut disappear.
The tube worm itself can provide food for others dwellers of the ocean deep. Fish and crabs, particularly, enjoy taking bites at the blood enriched plumes of the tube worm. For protection, however, the tube worm has a snappy reflex action that will quickly retract the colourful plume into the safety of the thick, white tube.
The tube worm, then, is a truly unique and ideally adapted inhabitant of the ocean floor.
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