Anatomy
The blue mussel (Mytilus edulis) has the white posterior adductor muscle, which must be cut to allow the valves to open fully.
The outer shell of the mussel is composed of two hinged valves that protect it from predators and desiccation. The leaflets are attached on the outside by a ligament and close when needed thanks to a powerful internal muscles. The shell of the mussels has several functions, from the soft tissue support to protection against predators and desiccation.
The shell is composed of three layers. In the pearl mussel is a layer of iridescent nacre (mother of pearl) composed of calcium carbonate is continuously secreted by this layer, the prismatic layer, is a middle layer of the white crystals of calcium carbonate in a protein matrix, and the periostracum is an outer layer that looks like a skin pigment. The periostracum is composed of a protein called Valerie, and their function is to protect the prismatic layer from abrasion and acid dissolution.
Like most bivalves, mussels have a large organ that acts as a foot, like a tongue in shape, with a groove on the ventral surface is continuous with the byssus pit. This hole ejects a sticky discharge that enters the groove and hardens gradually when it comes into contact with seawater. This forms an extremely strong thread called byssus and with which the mussel attaches to its substrate. The byssus is also used by mussels as a defensive measure against predatory molluscs.
Feeding
Mussels are filter feeders, feeding on phytoplankton and suspended organic matter. The mussels filter the water through an opening on the edge of the mantle, the water enters the cavity shovel by the action of the cilia located on the gills. The uneaten food is expelled through another opening in the mantle. The palps of the mouth located around the particles are selected to be ingested.
A bag that empties into the stomach secretes a gelatinous rod called hyaline style that stands in the stomach and kept spinning in the style sac by cilia. The rotation of the stem lens helps to dissolve the surface layers, which releases the digestive enzymes it contains. Once digested gift directed to the digestive gland or captured by amoebocyte which are the blood cells of molluscs. These cells have immune response functions or digestive. On the tract is responsible for diapedesis, which is the function through the mantle to expel unwanted particles or undigested remains.
Distribution and habitat
Marine mussels are abundant in the lower and middle intertidal zones in temperate seas throughout the world, in the northern hemisphere and in the south.
Another marine mussel species live in tropical intertidal areas, but not the same as those of the temperate zones.
Certain species of marine mussels prefer to live in salt marshes or quiet bays, while others thrive in pounding surf, completely covering exposed rocks washed by the waves. In addition, some species have colonized abyssal depths around hydrothermal vents.
Mussels require a constant supply of fresh, clean, not muddy depths. They prefer water with a substantial mineral content, because they need calcium carbonate to build their shells. Temporarily survive out of water.
Uses