diatom frustule
“Colour-enhanced image of a diatom frustule. The frustule is the silicon cell wall that acts as a skeleton to support the single-celled diatom. In this image only the frustule and none of the cell contents remain. Diatoms have chloroplasts and can use sunlight to produce food. They are a major component of plankton in both fresh and salt water.” 

diatom frustule

Colour-enhanced image of a diatom frustule. The frustule is the silicon cell wall that acts as a skeleton to support the single-celled diatom. In this image only the frustule and none of the cell contents remain. Diatoms have chloroplasts and can use sunlight to produce food. They are a major component of plankton in both fresh and salt water.”