Transmission Light Microscopy

This gallery is a selection of differential interference contrast (DIC) and darkfield imagery of microorganisms collected from salt and fresh water habitats. All imagery was captured using an Olympus BX51 microscope.

This is a focal plane stacking of Elodea canadensis in polarised light with retarder.

This is a focal plane stacking of Elodea canadensis in polarised light with retarder.

The cell walls of this filamentous algae appears to glow pink and green-cyan. What is happening is that the molecules making up the outer and inner cellulose cell walls are aligned in different directions and so the plane-polarised light that passes through is rotated through different degrees.

This is a focal plane stacking of Elodea canadensis in polarised light with retarder.

Vascular bundle of Elodea canadensis running up the central of the frame as imaged in polarised light.

Cells of a moss leaf with vascular bundle running horizontally across centre of the frame.

Freshwater cyanobacteria magnified around 100 times.

Freshwater cyanobacteria magnified around 400 times.

Collected from a pond in the Wicklow mountains, this is a Micrasterias desmid imaged in DIC.

Imaged in DIC, this is a Cosmarium desmid which has divided in two through mitosis.

Tetmemorus desmid floating next to a leaf of sphagnum moss. Imaged in darkfield polarised light.

A desmid is seen sandwiched between two leaves of sphagnum moss in polarised light.

A Springtail insect entangled in filamentous algae. Imaged in DIC at approximately 100x magnification.

Spirostomum is a long worm-like ciliate protist which can contract its body by greater than 50% in a very short space of time and this moment catches that event. You can see the rows of cilia running longitudinally along its body which sweep the water past it during locomotion.

Belonging to the kingdom Protista, Paramecium are agile creatures whose hydrodynamic propulsion in the low Reynolds number regime is achieved by rapid synchronised beating of the thousands of cilia carpeting its outer body.

The intake of food is achieved by the beating cilia lining its oral groove, which induce a circular rotating vortex in the surrounding local environment and thereby funnel small debris into its mouth. The food particles are stored in membrane bound compartments called vacuoles which breakdown the food through chemical reactions catalysed by enzymes.

Paramecium feed on the biofilm encapsulating a strand of filamentous Spirogyra algae. The cell nuclei and cytoskeletal network are visible in the filamentous algal cells. The globular spots on the cytoskeletal filaments are motor proteins which ‘run’ along these microtubule ‘highways’. The green structures are the chloroplasts which are helically wound within the interior of the cells and produce sugary food and oxygen as a waste product through photosynthesis.