Sea worms are unusual creatures. Many of them look like fantastic flowers or bright flat ribbons, and there are species that cause a shiver of horror with their appearance and habits. In general, the sea worm is a very interesting creature. It can be prickly-headed, polychaete, ringed, flat, hairy, and so on. The list is really huge. In this article, we will get acquainted with several types in more detail.
Tubular polychaete marine worm
The sea worm, whose photo looks like an exotic flower, is called tubular polychaete or "Christmas tree". This striking 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 Oceans. Preference is given to shallow depths, coral thickets and clear water.
To feel protected, this marine worm builds a lime tube from calcium and carbonate ions. The animal extracts its building material directly from the water. For a bunch of ions, the "Christmas tree" allocates a specialorganic component of the two oral glands. As the worm grows, the tube has to be added, adding new rings to the end of the old shelter.
The larvae of the polychaete tubeworm are responsible for choosing a place for a house. They only start building on dead or weak corals. Sometimes they gather in entire colonies, but single houses are also quite common. Growing, corals hide the tube, leaving only an elegant multi-colored “herringbone” on the surface. By the way, the color of the sea worm is really bright and saturated. It comes in blue, yellow, red, white, pink, mottled and even black. There are a huge number of options. Non-fast specimens combine different colors.
A beautiful outdoor "Christmas tree" is not just a decoration, but gill rays that do the work of the organs of nutrition and respiration. Each marine worm has two spiral gill rays.
Polychaete annelids take care of their safety at the stage of building a house. The lime tube has a tight lid, at the slightest threat the worm is instantly drawn in and closes the entrance.
Depending on the species of Spirobranchus giganteus, they live from 4 to 8 years.
Polychaetes
Polychaetes belong to the type of annelids, class Polychaetes. More than 10 thousand species live in nature. Most of them live in the seas and lead a bottom lifestyle. Separate families (for example, Tomopteridae) live in the perialal (open sea or ocean that does not touch the bottom). Several genera live in fresh waters,for example, in Lake Baikal.
Sea Sandbag
One of the most common representatives of polychaetes is considered a ringed polychaete marine worm, whose name is marine sandworm. 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 individual 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 each contains paired bushy gills.
Sea sandworm strengthens the walls of its dwelling with mucus. The length of the mink is about 30 cm. Being in the house, the worm places the front end of the body in the horizontal section of the mink, and the rear end in the vertical section. Above the head end of the worm, a funnel forms on the ground, as it constantly swallows bottom sediments. For defecation, the sandworm exposes the rear end of the mink. At this point, the sea worm may become the prey of a predator.
Nereid
Nereida is a marine annelids. 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 a head with tentacles, a mouth, jaws and two pairs of eyes. The sides of the segments are equipped with flat processes similar to lobes. Hereconcentrated numerous long bristles.
A Nereid's breathing involves the entire surface of the body. Annelids, which are familiar to everyone, also breathe. The nereid moves, quickly sorting through the blade-like outgrowths. In this case, the body rests on the bottom with bunches of bristles. This marine annelids includes algae and small animals that are enough for their jaws on their menu.
Features of breathing
The breathing method used by Nereids can be considered an exception to the rule for this type of worm. How do the rest of the annelids breathe? What is common in the breath of marine annelids? Breathing of most species occurs through the gills, which are located on outgrowths-lobes. The gills are equipped with a large number of capillaries. Enrichment of blood with oxygen comes from the air, which is dissolved in water. Here, carbon dioxide is released into the water.
Marine flatworms
In the depths of the ocean there is another class of worms - marine flatworms. They are called ciliated or turbellarians. More than 3.5 thousand species are assigned to this class. The body of representatives is covered with ciliary epithelium, which helps to move. Some representatives of ciliary worms can only be seen under a microscope, but there are species that reach 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. Moves aroundhe crawls or swims. It is bilaterally symmetrical. Turbellarians have a flattened oval or elongated body. On the front of the body are the sense organs, and the mouth on the ventral side.
The digestive tract of eyelash worms varies by species. It can be quite primitive or quite complex, with branched intestines.
Some species of marine turbellarians are discreet and inconspicuous, but there are bright multi-colored beauties that are simply impossible not to notice.
