Sea worms are unusual creatures. Many of them look like fantastic flowers or bright flat ribbons, but there are species that cause trembling horror with their appearance and habits. In general, a sea worm is a very interesting creature. It can be spiky-headed, multi-bristled, ring-shaped, flat, hairy and so on. The list is really huge. In this article we will get acquainted with several types in more detail.
Sea worm tubular polychaete
A sea worm, the photo of which looks like an exotic flower, is called a tubular polychaete or “Christmas tree”. This vivid species belongs to the Sabellidae family. The animal's Latin name is Spirobranchus giganteus, and the English name is Christmas tree worm.
This species of marine worms lives in the tropics of the Indian and Pacific Ocean. Preference is given to shallow depths, coral thickets and clear water.
To feel protected, this marine worm builds a calcareous tube of calcium and carbonate ions. The animal extracts its building material directly from the water. For a bunch of ions, the “New Year tree” distinguishes a special organic component from two oral glands. As the worm grows, the pipe has to be added, adding new rings to the end of the old shelter.
The larvae of the multi-bristle tubular worm are responsible for the choice of a place under the house. They begin construction only on dead or weak corals. Sometimes they gather in whole colonies, but single houses are quite common. Expanding, corals hide the tube, leaving on the surface only an elegant multi-colored Christmas tree. By the way, the color of the sea worm is really bright and saturated. It is blue, yellow, red, white, pink, mottled-mottled and even black. There are a lot of options. Slow individuals combine different colors.
A beautiful outdoor “tree” is not just a decoration, but gill rays that perform the work of the organs of nutrition and respiration. Each marine worm has two spirals of gill rays.
Polychaete worms take care of their safety during the construction phase of the house. The calcareous tube has a tight lid; at the slightest threat, the worm moment draws in and slams the entrance.
Depending on the species, Spirobranchus giganteus live from 4 to 8 years.
Polychaete
Polychaetes belong to the type of annelids, the class Polychaetae. In nature, they live more than 10 thousand species. Most live in the seas and lead a bottom lifestyle. Individual families (e.g., Tomopteridae) live in the peralial (open sea or ocean, not touching the bottom). Several genera live in fresh waters, for example, in Lake Baikal.
Sandblast
One of the most common representatives of polychaetes is considered to be the ringed multi-bristled sea worm, whose name is sea sand gull. In Latin, it sounds like Arenicola marina. The animal is quite large, its length reaches 20 cm. This marine worm lives in arched minks dug in the bottom sand. The food for this species is the bottom sediment, which the worm passes through the intestines.
The body of an adult consists of three sections - thorax, abdomen and tail. The outer cover forms secondary rings that do not correspond to segmentation. There are 11 abdominal segments in the body of the worm, and in each there are paired bushy gills.
Sea sandblast strengthens the walls of his home with mucus. The length of the mink is about 30 cm. While in the house, the worm locates the front end of the body in the horizontal section of the mink, and the rear in the vertical. A funnel forms on the ground above the head end of the worm, as it constantly swallows bottom sediments. For defecation, the sandgun exposes the posterior end of the mink. At this point, the sea worm can become the prey of a predator.
Nereid
Nereida is a marine annelid worm. It is a creeping species that serves as food for many marine fish. The body of the worm consists of segments. At the front point is the head on which the tentacles, mouth, jaw and two pairs of eyes. The sides of the segments are provided with flat processes similar to lobes. Numerous long bristles are concentrated here.
In Nereids, the entire surface of the body is involved in breathing. Ringed earthworms, which are familiar to everyone , also breathe. The Nereid moves, quickly sorting out with lobiform outgrowths. In this case, the body rests on the bottom with tufts of bristles. This marine ringworm includes seaweed and small animals in its menu, which are missing from the jaws.
Breathing features
The breathing method used by the Nereids can be considered an exception to the rule for this type of worm. How do the other representatives of the ringed breathe? What is common in the breath of marine annelids? Most species breathe through the gills, which are located on outgrowths-lobes. The gills are equipped with a large number of capillaries. The enrichment of blood with oxygen comes from air, which is dissolved in water. Here, carbon dioxide is released into the water.
Marine flatworms
In the depths of the ocean, another class of worms is found - flat marine worms. They are called ciliary or turbellaria. This class includes more than 3.5 thousand species. The representatives' body is covered with ciliary epithelium, which helps to move around. Some representatives of ciliary worms can only be examined under a microscope, but there are species reaching 40 cm in length. Among flatworms, there are not only free-living marine species, but also parasitic ones, including tapeworms.
Sea flatworm is most often a predator. He moves crawling or swimming. It is a bilaterally symmetrical animal. Turbellaria have a flattened body oval or elongated. On the front of the body are the senses, and the mouth is on the abdominal side.
The digestive tract of ciliary worms depends on the species. It can be very primitive or quite complex, with a branching intestine.
Some types of marine turbellariums are discreet and inconspicuous, but there are bright multi-colored beauties, which are simply impossible not to notice.