Algae and cyanobacteria
Diatoms
Diatoms (Bacillariophyta)
Single cells in glass boxes. Many boat-shaped diatoms glide slowly back and forth with no visible means of movement.
What to look for
- Golden-brown chloroplasts inside a clear, rigid shell (frustule) of two overlapping halves.
- Fine lines or dots on the shell, best seen when the cell is empty.
- Pennate (boat or needle shaped) species glide using a slit (raphe) along the shell; Bacillaria forms colonies that slide like a deck of cards.
Size in the field
Most are small: 400× shows the shape; patterns need oil immersion.
Where to find it
The brown slippery film on stones, plants and mud; almost every sample has some.
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