Muck

Mulm ( ndd. Molm , 'disintegrating earth, dust'; see Mull ) is a loose sediment of organic material, mostly consisting of plant residues , with bacteria , minerals and metabolic end products .

Origin of the word Mulm

The word mulm has been attested since the 17th century in the form molm in Low German . This is a substantivized m derivation of the verb grind → crush them and goes back to the same root, as well as mulch . The word melm also denotes sand in old West Germanic languages ​​and ore in the Scandinavian languages ​​in the form of malm .

As an adjective, it means queasy , rotten. The metaphorical meaning derived from this for "uncomfortable" is relatively modern and has only been documented since the 20th century.

Mulm in the forest

When dead wood decomposes, humification begins . Then one no longer speaks of wood, but of sludge , which consists of wood shavings and excrement of dead wood insects .

Mulm caves

Mulm cave on the trunk of a common beech

A sludge cave is the accumulation of sludge in the trunk of a dead, hollow, living or dead tree. They are among the rarest habitats in Germany , especially the xylobiont beetles.

Mulm in the water

As sludge or wulch also the precursor of is sludge (digested sludge) understood, for example, the bottom of an aquarium , fish pond , bathing or swimming pond or parts thereof covered. This sludge consists largely of detritus , microorganisms ( single cells ), bacteria and trace elements . It is more coarsely structured than mud and can also contain dead plant parts. The nitrates and tannins resulting from working through the sludge get into the filter and become filter sludge there . Is also what to suspended matter from penetrating into the ground as sludge or Mudde designated.

Mulm has various influences on the aquarium:

• Mulm offers an ideal settlement area for Nitrobacter , which break down pollutants
• Mulm stabilizes the aquarium climate with a favorable redox value .
• Small organisms live in the Mulm, which fish and shrimp serve as food
• Mulm can rot if there is insufficient oxygen ( anaerobic ).

Mulm in the sound engineering

Mulm is a special technical term in creative sound recording technology for dark, blurred and unclear, washed-out sound.

Individual evidence

1. ^ Speight 1989, Schmidl 2003

Web links

Wiktionary: Mulm  - explanations of meanings, word origins, synonyms, translations

• http://www.waldwissen.net/wald/naturschutz/arten/lwf_schatztruhe_buche/index_DE Treasure chests in the beech forest