VIRTUAL POND DIP!
Descriptions of some of the commonest pond animals
Protozoa (Paramecium)
This is the Paramecium which is one of the larger protozoa or singe-celled animals commonly found in a pond. Many protozoa are very small but the larger Paramecium are about 0.3mm which is just large enough to be seen as a speck swimming in pond water. A compound microscope at 40 to 100X should show more detail if you can catch one with an eye dropper and place it on a slide.The older text books called them 'slipper animalcules' as with careful study under a compound microscope they do look like a slipper. The Paramecium is often used as one of the classic examples of a protozoan and are widely illustrated in biology textbooks.
Micscape has an article on Paramecium by Mike Morgan and Mike Samworth showing a beautiful image and a diagram explaining it's structure. If you look at the article use the Go Back feature on your browser to return to the Pond Dip.
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Protozoa (Stentor)
This is the Stentor, which is a trumpet-shaped protozoan, or single-celled animal and is commonly found in a pond. It is one of the largest protozoans to be found (up to 2mm long) and it is larger than some multi-celled pond animals.When it is attached to a leaf, twig etc it adopts the trumpet shape shown and the ring of hairs around the trumpet rim draw in water together with the smaller organisms on which the Stentor feed. When the Stentor swims it adopts an oval shape.
The Stentor is often green in colour because of the algae (single-celled plants) associated with it. Micscape has an article on Stentor describing where in the pond to look for it, together with images showing its various features. If you look at the article use the Go Back feature on your browser to return to the Pond Dip.
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Cyclops
This multi-celled animal is called a Cyclops and is one of the easiest pond creatures to see and identify even with the naked eye. The female often carries a pair of egg sacs and is a fast swimmer, which you will find out if you try to catch it with a pipette (or eye dropper)! It possesses just one eye hence it was named after the Greek mythological creature of this name.It is a Crustacean and similar species are abundant in both fresh and sea water, and are typically 0.5 - 3mm long. They are usually a drab green or brown but can be quite brightly coloured. The class of Crustacea to which the Cyclops belongs, the Copepoda, form a very important part of the marine plankton (free swimming microscopic creatures) as they are part of the food chain for many larger animals.
Micscape has an introductory article on Cyclops by Mike Morgan in the library. If you look at the article use the Go Back feature on your browser to return to the Pond Dip.
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Hydra
The hydra is a fascinating animal to find in a pond but may need a little patience to see when present. It is a very distinctive creature with its tentacles, but when the water is first collected and examined the disturbance will probably make it contract into a blob. If the pond water with some weed is left to stand for a while the hydra, if present, may be seen by eye attached to the wall of the jar, or the vegetation. They are often pale brown or green. The underside of floating weed like duckweed is a particularly good place to find them.Hydra have many fascinating features, one in particular is that they can reproduce asexually by budding where a smaller hydra grows off the body of the adult and eventually separates. The tentacles have stinging cells which they use to capture prey like small water fleas. They are a classic organism for biology students to study as they are a representative member of the Phylum Coelenterata or Cnidaria. The cnidarians are the most primitive animal where the cells are organised into different layers.
There is an article on hydra by Mike Morgan in the Articles library. If you look at the article use the Go Back feature on your browser to return to the Pond Dip.
Or return to the Pond Dip now.
Water flea (Simocephalus)
Water fleas are the common name for a group of freshwater animals which are a delight to observe under the microscope. Their beating heart, compound eye and moving limbs can all be easily seen as they have a transparent shell. Water fleas includes the well known genus Daphnia which are often available in pet shops for fish food. The Simocephalus illustrated is a similar water flea but is usually larger and may be more easily noticed than the Daphnia.If a jam jar of pond water is examined from the side, the water fleas if present can often be seen as small transparent organisms 0.5-3mm long moving upwards by jerking movements of their second antennae. Hence their common name water flea, although they are not fleas.
One of the delights of examining water fleas is that the females often carry live young, and if you are lucky they may give birth while you are examining them. Water fleas are Crustacea, and are often grouped under the now outdated order Cladocera.
This tiny globular shaped animal is a water flea of the Chydoridae genus. (Click on the other water flea in the pond afterwards if you haven't already to learn more about water fleas). Whereas the other water flea is usually found swimming in the open water the Chydoridae are smaller (typically 0.5mm) and are commonly found scuttling about the water weed.
The second antennae which the larger water fleas like Daphnia use to swim jerkily through the water, is smaller in the Chydoridae which swims more smoothly through the water.
Simple guidelines to start pond dipping
Note if you are a youngster, please do not collect from areas of water without supervision from parents or teacher.Simple steps:
- find a pond with clear water with plenty of weed at the edge, your garden pond may be fine
- grab a handful of weed and transfer with some pond water to a bottle with lid
- back home, transfer a little weed with water in a petri dish for closer examination with a 10X hand lens or low power stereo up to 40X
- the larger organisms like water fleas, cyclops can be enjoyed at this magnification although the compound microscope will reveal more detail
- smaller organisms like protozoa will be seen as tiny white specks under a lens or stereo, try to collect some in a pipette or eye dropper and transfer to a microscope slide
- put four blobs of vaseline around the water drop and gently put on a cover slip to slightly trap the creature without squashing
- examine under a compound microscope, magnifications between 50X and 200X should provide plenty of fascinating detail
More detailed information on pond dipping and important notes on collecting can be found in the Micscape Pond Dipping article by Roy Winsby.
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