Earthworm granules

Earthworm granules are being actively researched in Environmental Studies for their potential in both stratigraphic and dating studies.  They are deposited in soils and sediments by most UK earthworm species, and vary in size from a maximum of about 2.5 mm (see Lumbricus terrestris large example) down to as little as 50 µm.  The granules are aggregations of calcite crystals (see Lumbricus terrestris close-up) with varying degrees of crystal alignment and different amounts of intercrystalline cement.  They have largely unsystematic morphologies both within and between species, but often show some characteristic shapes.  The tendency towards parallel constituent crystals in Octolasion cyaneum (see Octolasion cyaneum 1 and Octolasion cyaneum 2), for example, appears to be a fairly constant phenomenon, as does the elongated (frequently banana-shaped) form in granules of Lumbricus rubellus (see Lumbricus rubellus).  However, in all cases, characteristic morphologies are only part of a species assemblage, and other less defined shapes are also present.

Lumbricus terrestris large example 

 

 

 

 

 

 

 

 

 

 

Lumbricus terrestris close-up 

 

 

 

 

 

 

 

 

 

 

Octolasion cyaneum 1 

 

 

 

 

 

 

Octolasion cyaneum 2 

 

 

 

 

 

 

 

 

 

 

 

Lumbricus rubellus