Exploration of the Pond

This gallery is an exploration of the microscopic flora and fauna found in fresh water habitats.

Floating Aquatic Plant (Lemna minor)

Floating Aquatic Plant (Lemna minor)

Flatworm (Typhloplana sp.)

The green dots seen inside are its endosymbioants, Zoochlorella. Zoochlorella are alga cells which contain chloroplasts. The chloroplasts provde the flatworm with energy and the flatworm provides the zoochlorella with a safe and secure home.

Flatworm (Typhloplana sp.)

The green dots seen inside are its endosymbioants, Zoochlorella. Zoochlorella are alga cells which contain chloroplasts. The chloroplasts provde the flatworm with energy and the flatworm provides the zoochlorella with a safe and secure home.

Population Explosion of Flagellates

Configured for darkfield polarised light, here we image a population explosion of flagellated micro-organisms.

Rotifer

Just like the stream lines seen in vortex shedding from the wing tips of an airplane as it passes through moist air, in the second half of this movie clouds of flagellated protozoa make visible the twin vortex generated by a rotifers ciliated 'turbine'. By reducing the exposure time the tracks of the particles can be traced out, just like when one photographs the trailing lights of the traffic in a long exposure at night.

Peritrich Colony in Darkfield (DF)

Large colony of the bell shaped ciliate - Peritrich. The entire colony is attached by a single long slender stalk to the organic debris below. Peritrich are holozoic ciliates. This means that they have a mouth and acquire nutrients by engulfing solid organic matter. Their mouth consists of an elaborate food-catching apparatus that secures food by means of ciliary currents. The anterior end of each peritrich body forms a bulging peristome. The peristome is the blue coloured path seen in each cell and is defined as a fringe of small projections around the mouth of a capsule. In this case, the fringe is composed of cilia, all of which beat in synchronised motion, like a Mexican-wave. The motion induces a water currents in the local environment in the form of a vortex that causes food particles to spiral down the funnel where they are then guided into the vestibule along the adornal zone.

Peritrich Colony in DIC+DF

Close-up of a large colony of the bell shaped ciliate - peritrich. The colony mirrors the structure of a tree in that it has a trunk called a stalk made up of myonemes. The stalk breaks up into a series of branches at the end of each is the bell-shaped peritrich capsule.

The blue coloured path is the peristome, the structure that generates the beautiful instability in the local watery environment, the vortex that funnels food into its mouth.

Peritrich Colony

Starting at a magnification of around 100 times, the movie shows the scene from the above photos - the overall tree-like structure of a colony of Peritrich microorganisms. The movie then progresses to a higher magnification at over 200 times to examine the finer details of the organisms. You can see the 'turbine' spinning at the anterior end of the vestibule. In fact, this is not a turbine but a row of hair-like structures called cilia. The cilia beat back and forth in a synchronised motion which gives the impression of rotation. Returning to x100 we see the spring like reflexes of the peritrich stalk that anchors the colony to a substrate composed of organic debris. Next we transition to over 400 times magnification switching from dark field to differential interference contrast microscopy that gives a 3D like effect.

Peritrich Colony in DIC

A small colony of Peritrich imaged in differential interference contrast..

Close up of several Peritrich in a Colony

Here we can see the details of the Peritrich as we peer inside of its translucent body as imaged in differential interference contrast microscopy and magnified over 600 times.

Vorticella Colony in DIC

Vorticella Colony and Rotifer

A rotifer hunts for food among a large colony of vorticella.

The movie shows a swarming population of dinoflagellates collected from a bloom in a fresh water habitat. The movie shows sequential magnification of approximately 150 to 250 times imaged in DIC.

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

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.

Rootlet Ecosystem

A rootlet of pond weed provides the basis for a micro-ecosytem. Here we see Paramecium feeding on biofilms that encapsulate the rootlet.

Paramecium

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.

Here, a Paramecium bursaria glides along a filament of alga hoovering bacteria that populate the encapsulating biofilm.

Paramecium

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.

Paramecium

A gathering of Paramecium caress themselves through a tasty cloud of bacteria.

Diptera Larva

Muscle fibers within the body of a Diptera larva appear to glow yellow-orange in this compensated polarised light image.

Micrasterias Desmid

This green gem, a Micrasterias desmid floats in the abyss of the microcosmos.

Micrasterias Desmid

This green gem, a Micrasterias desmid floats in the abyss of the microcosmos.

Diptera Egg Mass

A gelatinous cocoon containing numerous embyro's.

Diptera Egg Mass

A gelatinous cocoon containing numerous embyro's.

Diptera Egg Mass

A gelatinous cocoon containing numerous embyro's.

Diptera Egg Mass

A gelatinous cocoon containing numerous embyro's.

Cyclosis in Canadian Pond Weed Elodea canadensis

Cytoplasmic streaming in the cells of Elodea canadensis (Canadian pondweed). You can see the diffraction spots of motor proteins pushing and tugging on the chloroplasts as the run along the cytoskeletal filaments.

Spirogyra

This is a close-up of that green pond scum that you sometimes see in ponds and canals. The cell walls appear to glow white due to the property of birefringence of the cellulose fibers that make up the wall.

Spirogyra

Spirogyra is a filamentous green algae named for the spiral arrangement of the chloroplasts within its cells. The helical arrangement is characteristic of the genus, which is a member of the Zygnematales. Commonly found in freshwater habitats, there are more than 400 species of Spirogyra.

Blue-Green Algae

Timelapse movie show the movement of blue-green algae. The locomotion of this algae is thought to result from the secretion of mucus slime...