Sunday, May 22, 2011

Life in a few Drops of Water: Desmids

This is the second in the series of images of some of the organisms found in just a few drops of water collected from a pond in a disused quarry on the edge of the moors in Weardale.
This is  a desmid - probably a species of Cosmarium. Desmids are typically constricted in the centre of the cell to form two mirror-image halves.

These are single-celled, photosynthetic algae that often have a patterned cell wall that's ...

.... most clearly visible after the cell has died and lost its chlorophyll.

This appears to be one half of a desmid that has broken at the bridge joining the two halves (known as the isthmus), revealing the fractured hole.

Coming next: Dinoflagellates


  1. What magnification was used here?

  2. The cell wall pattern reminds me of some old-fashioned glass candy jars that some of my various senior female relatives have possessed . . .

  3. Hi Frank, the microscope magnification was x400 (x10 eyepiece,x40 objective). The desmid is about 70 thousanths of a millimetre in diameter.

  4. Hi Jennifer, they'd make great glass scultures, wouldn't they? Have you seen Luke Jerram's glass models of bacteria and viruses at

  5. Hi Kristin, I could spend hours looking at these organisms...


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