Are invasives bad? Not always, researchers say

In 1988, a mysterious invader washed upon the New Jersey shore. The Asian shore crab likely arrived in ballast from commercial ships, and it found its new home to be quite agreeable. More than two decades later, the crab, ...

A crystal clear view of chalk formation

(PhysOrg.com) -- It has a beautiful, but also an unpleasant side: crystallization determines the shape of precious stones, but also causes the lime scale in washing machines. How this comes about, has been known for a long ...

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Mussel

The common name mussel is used for members of several families of clams or bivalvia mollusca, from saltwater and freshwater habitats. These groups have in common a shell whose outline is elongated and asymmetrical compared with other edible clams, which are often more or less rounded or oval.

The word "mussel" is most frequently used to mean the edible bivalves of the marine family Mytilidae, most of which live on exposed shores in the intertidal zone, attached by means of their strong byssal threads ("beard") to a firm substrate. A few species (in the genus Bathymodiolus) have colonised hydrothermal vents associated with deep ocean ridges.

In most marine mussels the shell is longer than it is wide, being wedge-shaped or asymmetrical. The external colour of the shell is often dark blue, blackish, or brown, while the interior is silvery and somewhat nacreous.

The word "mussel" is also used for many freshwater bivalves, including the freshwater pearl mussels. Freshwater mussel species inhabit lakes, ponds, rivers, creeks, canals, grouped in a different subclass, despite some very superficial similarities in appearance.

Freshwater Zebra mussels and their relatives in the family Dreissenidae are not related to previously mentioned groups, even though they resemble many Mytilus species in shape, and live attached to rocks and other hard surfaces in a similar manner, using a byssus. They are classified with the Heterodonta, the taxonomic group which includes most of the bivalves commonly referred to as "clams".

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