Bioerosion Process

Erosion of the substrate occurs in many steps and the process by which it occurs has, until recently, been a topic of debate.

Bioerosion occurs by the following steps*:

1. Penetration by the etching cell begins along the cell-substrate interface via mechanical and chemical means, dissolving the substrate around the contours of the cell forming an etching in the substrate. Historically, debate had sparked on whether it was just mechanical or chemical means involved (Rutzler and Rieger 1973) but now it is recognised that both are used (Cobb 1969).

2. As deeper etchings occur downward into the substrate, extensions(filopodia) from the edge of the etching cell come in contact with the substrate moving down into the gap made by the cell.

3. The filopodia eventually come together and surround a small fragment, removing it from the substrate and is then released into the aquiferous system where it is eventually expelled into the water.  

        

4. Once an etching cell has been involved in the etching process and engulfed a fragment, the cell disintegrates and more are regenerated.