The distribution of mussels is unlimited. The Arctic Ocean, the Pacific and Atlantic coasts, the Black and Azov Seas, the Hudson Bay, Greenland are just a small part of their habitats.
Very interesting marine creatures - mussels. The structure of their shells is characterized by a number of characteristic features due to their habitat.
Mussel habitat conditions
In the shallow water in saline seawater, mussels are attached to underwater reefs, breakwaters, and stones using bisus threads. The structure of the shells, great strength, as well as a streamlined shape give an excellent opportunity for their dwelling in the surf zone with a rapid current.
The life expectancy of mussels, living in different conditions, is different. Black Sea live about 5 years, northern - 10. True centenarians - Pacific mussels, living for three decades.
Mussels are absolutely unpretentious creatures:
- For them are unicellular algae, phytoplankton, bacteria;
- Food enters the body as a result of filtration of sea water;
- On a small area form many thousands of settlements - mussel banks;
- The infancy of the mussel passes among plankton, and when the eggs become larvae and overgrown with shells, they adhere to rocks, stones and any other hard surfaces.
Mussels: external structure
Mussels are bivalves. ссиня-чёрная раковина взрослого моллюска, покрывающая удлинённое тело, имеет форму клина, а также гладкую поверхность с тонкими линиями нарастания. Light-yellow or black-blue pine and black shell of an adult mollusk covering an elongated body, has the form of a wedge, and also a smooth surface with thin lines of growth. The shape of the shell is determined by the species and subspecies of the mollusk.
The external structure of the mussel has distinctive features:
- Symmetrical left and right valves are connected by a muscular tissue and a flexible ligament;
- The valves close very tightly as a result of contraction of the adductor muscle and protect the body of the mollusc from any external action;
- мидии; The tip of the shell is closer to the front edge - this creates a recognizable image of the mussel;
- цвет ; The outer surface of the shell has a calcareous composition and a dark color ;
- имеет слой перламутра – гипостракум. The inner part of the shell has a layer of nacre - gipostrakum.
– так формируются жемчужины. A grain of sand that has fallen into the space between the leaf and the mantle is gradually enveloped in mother-of-pearl - this is how the pearls form.
Mussels: the internal structure
которого выглядит следующим образом: Mussel is a shellfish whose structure is as follows:
- The body is formed from the trunk and leg, deprived of the motor function due to the sedentary lifestyle of the mollusk.
- The head is absent, there are no such digestive organs as the salivary glands, jaws, pharynx.
- The mouth is at the base of the leg and connects with a short esophagus opening into the stomach.
- The glands secrete the bisus - strong threads of protein origin, which are necessary for fixing on the bottom of the reservoir.
- в задней части. The body is covered by a mantle, which falls free folds on the sides and fuses in the back. Siphons are formed here, that is, food and air tubes.
- определяет дыхательную систему и систему питания . The internal structure of the mussel determines the respiratory system and the food system .
- Mollusks breathe with the help of gills under the mantle and serve as a filter, which pumps up to 70 liters of sea water per day. On the gills is a lot of cilia, due to their work on the body is water, which delivers to the oral blades nutrient microorganisms.
- Inedible particles, as well as excreta, are excreted by the excretory siphon of the mussel.
- The structure of the heart is represented by two atriums and one ventricle, from which two aortas, dividing into several arteries, depart.
- The circulatory system is not closed.
- The nervous system is represented by the nerve nodes that adhere to each other with nerve trunks.
- Tactile organs are represented by oral blades and tactile cells located along the edge of the mantle, in the lamellar gills and in the leg.
Mussels are used in different spheres of life. The structure of beautiful shells makes marine creatures almost indispensable in the manufacture of souvenirs and ornaments. The pearlescent layer gives a special decorative effect to the products.
At the same time, mussels are a real find for true connoisseurs of sea delicacies. Residents of seacoast since childhood are familiar with the special ritual of cooking mussels: they are collected from the sea day, cleaned and cooked right on the beach. On an industrial scale, mollusks are caught by dredges, which are raked from the seabed all in order for the subsequent sorting of the caught.
Mussels, which have a delicate delicate taste, can decorate any feast: they are fried, boiled, smoked, marinated and even eaten alive.