The Pompeii worm. Source
The Pompeii worm. Source

On average, humans do not have to deal with temperatures that exceed 35° C, with the hottest human populated places staying between 33-36°C, with occasional bursts of heat reaching 42°C. When we get hot, we always have options – find shade, take a layer of clothing off, find some cool water. Life, however, is not quite as simple for all creatures on this earth and this is a tale only too true for the Pompeii worm (see above). The Pompeii worm, Alvinella pompejana, is a deep sea polychaete and is known as the most heat tolerant animal on earth due to its ability to live in temperatures reaching 80°C. It is classed a thermophile, meaning that it lives and survives in an area of extreme temperature, which in this case is extreme heat. The first pompeii worm was first identified almost 21 years after its habitat, the hydrothermal vent system, was first discovered, and about 10 years after it was first discovered by french marine biologists, showing how difficult this environment is to study. The body of the worm can reach 13cm in length, and they are naturally pink in colour with a grey coat, with large tentacle like gills on the head, red in colour due to the presence of haemoglobin. Curiously, the head of the worm rests in temperatures as low as 22° C, while the tail of the worm resides in temperatures reaching 80°C, showing an extreme diversity across the worm in temperature tolerance.

 

The head of the Pompeii worm sticks out of the tube in which it builds and resides. Source
The head of the Pompeii worm sticks out of the tube in which it builds and resides. Source

It’s getting hot in here, so put on all your tubes!

The Pompeii worm attaches itself to the smokers of hydrothermal vents, usually called black smokers due to the amount of black material that they emit, which contains a high level of sulfur and is therefore highly toxic, not only to the worm but to all life living in the community. To combat the high temperatures and toxicity, the Pompeii worm builds itself a paper like tube, attached to the chimney of the smoker, which is heat resistant. Around the smokers of the hydrothermal vents, there can eventually be a whole colony of these tube like structures. While the head of the worm sticks out of the tube, it is immersed in water that is much cooler than the water which the tail is exposed to. When searching for food, the worm leaves the tube altogether and can reach water as cold as 10°C. This diversity in temperature that the worm is exposed to makes it one of the most complex heat tolerant animals currently known to science.

 

They’re so symbiotic together

The Pompeii worm without N. profundicola present and hence a lack of the grey fleecy coat usually seen. Source
The Pompeii worm without N. profundicola present and hence a lack of the grey fleecy coat usually seen. Source

The Pompeii worm does not work alone while building itself a home. On the back of the worm is a thermophilic bacteria, which forms a fleece like cover over the worm, providing the grey colour on an otherwise pink worm. The bacteria, Nautilia profundicola, form a symbiotic relationship with the worm, meaning that both the worm and the bacteria benefit from the arrangement. Via tiny glands on its back, the worm secretes mucus, containing high levels of eurythermal enzymes, which feeds the bacteria and in return, the bacteria act as a heat shield towards the worm, or at least providing a layer of insulation.

The bacteria are highly specialised, in that they also detoxify the surrounding water. Within the clouds of black material that are emitted by the smokers are high concentrations of many toxic chemicals, not just sulfur. Heavy metals, such as lead, cadmium, zinc and copper are also contained within these clouds, which would make life almost impossible inside theses vents. The act of creating insulation for the worm shifts through the chemicals inside the tube and starts to create a detoxified environment. Recent investigation of the pompeii worm itself has also shown that the gills of the worm detoxify the sulfide in the water, which could possibly explain the need for the head to stick out of the tube. The bacteria are also chemolithotrophs, meaning they not only aid the ecology of the pompeii worm, but also the general ecology of the hydrothermal vent community.

Everyone wants a piece of the bacteria

The bacteria, N. profundicola, could show to be particularly usesful in the scientific community. Researchers investigating the symbiotic relationship between that of the Pompeii worm and N. profundicola have suggested that the enzymes used in the thermal insulation of the worm could be isolated and used in a variety of areas. These include pharmaceutical production, making batch production easier, and in food processing by making the food more heat tolerant and safer to eat in things such as ready meals. The toxicity lowering properties that the bacteria exhibits could also be used combat toxic wastelands. The problem, however, is gathering enough specimens of either the Pompeii worm or the bacteria to be able to isolate the enzyme. The deep sea and hydrothermal vent environment is difficult to replicate in a laboratory, as the combination of the extreme temperature and toxicity is incredibly dangerous to humans and also difficult to contain, were it possible to create. With the progression of science, it may one day be possible to isolate the enzyme, meaning that the symbiotic relationship between the Pompeii worm and N. profundicola could eventually an incredibly useful relationship in many areas of human life.

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