A Methods Manual for the Collection, Preparation and Analysis of ...

4. Diatoms – Colony formation and attachmentDiatoms release mucilage through various structures in the cell wall to facilitate locomotionor attachment of the cells to various substrata. Mucilage secretions can also be used to formcolonies of various patterns. This material must be eliminated for microscopic detailedexamination of the cell wall. After a diatom sample has undergone the necessary steps toprepare it for light microscopy at high magnifications all that can be seen is a silica structure.This skeleton or cell wall is typically referred to as the frustule. Chemical treatmenteliminates all organic material from both inside as well as outside the cell walls.1 23 45 6Fig. 1 shows the attachment of Cymbella sp. to a substratum with a mucilage stalks. Fig. 2 showsEncyonema caespitosum inhabiting a mucilage tube. Fig. 3 shows the dichotomously branchingmucilage stalks to which cells of Gomphonema sp. are attached. Fig. 4 Melosira varians with cellsattached both to the substratum and each other by mucilage pads. Fig. 5 stellar colonies of thediatom Asterionella formosa. Fig. 6 Achnanthidium minutissimum attached by means of mucilagestalks to Lyngbya sp.6