Psammon

The term Psammon (sometimes Psammion ) is derived from the Greek word psammos "sand" from and refers to the totality of living on and in the sandy substrate of the aquatic organisms. The Psammon is thus a portion of the benthos, which is the totality of occurring on and in the bottom of the water body.

Studies of microbiology sandy river bank there since 1926, when D. Sassuchin published the results of his microscopic studies on the Oka in Russia. In 1927, the term Psammon was proposed by him, " analogous to the concept Edaphon ". The characteristic of the Psammon the rivers organisms belong to the groups of algae, rotifers, Bauchhärlinge, flatworms, nematodes, tardigrades and Little Borster.

Later the term Psammon was also established for the sandy shores of the seas. Similar to the sandy banks of the rivers is given by the wave action in the field of marine subtidal a highly unstable environment situation. Plants can take root or attach difficult in the sandy environment. Therefore, there are also a few organisms that graze on plants. The inhabitants of the Psammons are largely dependent on the utilization of detritus.

Due to the grain size of the sand, the composition of the fauna of the Psammons is determined. Most animals live in the spaces between the sand grains, the " interstitial System" or Mesopsammon. They are usually between 0.3 and 1 mm in size and thus belong to the meiofauna.

From the Polish biologists Wiszniewski the proposal of a tripartite division of the living space Psammon dates:

• Eupsammon - the part of the sandy shore or sand banks, which is above the water level and only slightly influenced by the waves is
• Hygropsammon - the part of the sand bank, which is in the range of the waves and soaked by the hygroscopicity of the water constantly perfect remains
• Hydropsammon - the part that is always completely covered by water