Plankton can be examined very easily, so for amateurs it is wise to start practicing microscopy this way, but even examining plankton requires some refinement: The proverbial "Miracle of Life in one Drop of Water" usually will be a great disappointment because of the low concentration of plankton organisms. You need a professional plankton net, made of fine gauze with a mesh size of about 0,05 - 0,02 mm. This net is pulled through the water several times or else you may filter some ten liters of water through such a net using a bucket. Samples thus collected should be kept cool and must be investigated as soon as possible. The plentiful amount of different forms is always overwhelming! Afterwards the sample is preserved by mixing 10 ml sample with 1 ml formaldehyde, but it is impossible to stabilize all types of organisms - only algae and animals with some kind of carapace will keep their shape. It is recommended to add some drops of glycerol to prevent desiccation and a small crystal of copper acetate to stabilize chlorophyll.

More detailed information will be found on the <tips for beginners and advanced> page.

It is particularly impressive to watch rotifers, small multicellular organisms, which are named after two special structures at their apex, which seem to whirl around like spinning wheels. Here are some pictures and clips.

Ceratella .		Asplanchna	Asplanchna	Asplanchna
				Please be patient! Buffering is under way ...
	clip Brachyonus .	clip Polyarthra
		Clips of some flagellatae		Please be patient! Buffering is under way ...
clip Ceratium .	clip Synura

Another interesting group are the very vivid unicellular Ciliates. Here some examples of Stentor, the trumpet creature.

Stentor .	Stentor

Some of the most beautiful algae are Desmids. Although they are not planktonic organisms, they occur very often in plankton samples. They are abundant in boggy areas and swamps of slightly acidic water. Squeeze the wet moss found in such places, sieve the water through a plankton net and you will find many different species!

Micrasterias .	Staurastrum	Spirogyra

A particularly fine group are Diatoms which produce skeletons of silica. These skeletons are extremely inert, so they are concentrated in the mud at the bottom of pools and lakes. To separate these skeletons a dried mud sample is heated with concentrated sulfuric acid in the open until all the organic impurities are destroyed, then the sample is washed repeatedly with water and finally immersed in alcohol. Allow a small amount of this sample to dry on the slide, then add one drop of toluene or xylene, followed by a drop of mounting medium, and after placing a coverslip on top you will possess a prepared microscopic slide.

More detailed information can be found on the <hints> page.

Arachnoidiscus .	Mastogloia

Although the structures of Diatoms can be seen with a normal microscope, they are so delicate that they can only be properly analysed using a scanning electronic microscope.

Copyright: webmaster@mikrohamburg.de