Confocal laser scanning microscopy

Confocal laser scanning microscopy (CLSM) overcomes some of the main limitations and disadvantages of conventional light microscopy and electron microscopy for imaging palynological specimens. 

CLSM is being used in the Palaeontology Department to create incredible images of our most important specimens.

Alternative to electron and conventional light microscopy

Although conventional light microscopy is the tool most widely used in the investigation of palynomorphs, it has limitations:

  • It fails to resolve the delicate morphological features found in many dinoflagellate cysts.
  • The low depth of field inherent in the optical system hampers the documentation of palynological objects.

In comparison, electron microscopy offers an enormous information gain and also avoids the depth of field problem. But it demands delicate, time-consuming preparation techniques, and the study of conventional strew mounts is not possible.

The application of CLSM to fossil dinoflagellate cysts offers an exciting alternative to both and has been used successfully (Feist-Burkhardt and Pross, 1999).

How does CLSM work?

  1. A point light source is directed onto the object plane.
  2. A point of emitted fluorescence light or reflected light is then directed to a photomultiplier through the detector pinhole and is displayed on a computer screen as a pixel.
  3. By scanning the object point-by-point and line-by-line, very thin and blur-free optical sections are recorded.
  4. A series of optical sections forms an image stack from which extended focus images, stereoscopic images and red/green anaglyphs can be produced.

Reference

Feist-Burkhardt S and Pross J (1999) Morphological analysis and description of Middle Jurassic dinoflagellate cyst marker species using confocal laser scanning microscopy, digital optical microscopy and conventional light microscopy. Bulletin du Centre de Recherches Elf Exploration Production, [1998] 22(1): 103-145.