A switching station

Ganglia are part of the peripheral nervous system. The peripheral nervous system includes all nerves outside the central nervous system (bundles of long nerve shoots with supporting cells) and small centers of nerve cells the ganglia.

A ganglion is a combination of mainly cell bodies (ganglion cells) with the nucleus of the nerve cell surrounded by cytoplasm without further shoots. This cell body with the nucleus as its center forms the metabolic center of the cell and is sensitive to stimuli. Ganglia function as switching stations for nerve impulses.

Which freshwater algae do we see?

In the video you will find some algae found in fens in the ‘Wortel Kolonie’ located in Belgium. The ‘Wortel Kolonie’ is a beautiful protected nature reserve with a complex of buildings that served as an asylum for vagrants long time ago. (Here you will find the information in Dutch, English, French and German).

This nature reserve contains a few shallow fens. On a summer day in July, some water samples were taken from two fens using a trawl net with a mesh size of 30 microns. Without examining these samples in depth, more than fifty different organisms, phyto- and zooplankton, were found. Only a few of them are shown in the video. In one of the algae we see a oogonium.

The names of the organisms in the video are deliberately omitted here, to give hydrobiology enthusiasts the opportunity to identify the organisms themselves.

One Coleps makes two, cell division

• Alga: Coleps
• Order: Prorodontida Corliss, 1974
• Family:  Colepidae Ehrenberg, 1838
• Genus: Coleps Nitzsch, 1827

Coleps is a barrel-shaped ciliate, notable for its regularly arranged ectoplasmic shields, or platelets, of calcium carbonate. The covering with the scales is sometimes completely or partly absent immediately after an amitotic division (direct cleavage of the nucleus without the formation of mitoses). This is clearly visible in the accompanying video. Cell division took approximately 45 minutes. The color of the cell is usually brown and is less determined by the color of the food consumed than with other ciliates.

Family Cochliopodiidae de Saedeleer, 1934

For this Amoeba see the excellent website of the world famous amoeba specialist Ferry Siemensma.

"DIAGNOSIS: Amoebae partially enclosed within a flexible cuticle or wall (tectum) usually covered with microscales (Cochliopodium) or with a dorsal fibrous cell coat without scales (Ovalopodium). The covering is open along the region of attachment to the substratum; with no well-defined aperture.

Amoebae in this family have been classified as testate amoebae by Page (1987b) but are included in this chapter because they resemble euamoebae at the light microscope level. Typically they have a distinct hyaline zone often with short subpseudopodia, and a prominent central granular hump."

Which diatoms do we see here?

The Macrofauna Werkgroep Groen Hart Leudal in The Netherlands, found some diatoms in the river Swalm near their clubhouse. It is a challenge to name diatoms if the cell contents are still present in the silica skeleton. The organic content should be removed first with the help of chemicals. Yet an attempt can be made to identify these still living tiny algae, which were caught on video with the help of the Motic inverted microscope AE31E with Motic PlanApo 20X and 40X objectives and the Moticam cameras 1080 and S6.

The Swalm is a small river in Germany and the Netherlands. Its source is in North Rhine-Westphalia, Germany. The Swalm flows into the Meuse across the border with the Netherlands. Its total length is 45 km.

The wetland overgrown with trees and heath/bog areas along the Swalm provide a diverse habitat for fauna and flora. Frogs, dragonflies, damselflies, blue throat, kingfisher and golden oriole are to be found as are water crowfoot, bog myrtle and other rare plants. Brown trout, barbel and chub are at home in the river; along the river banks are also various members of the beaver rat family.

Which diatoms do we see in the video?

A find on the beach

The shells or shields on the back of the various species of cuttlefish Sepia spec. consist of brittle lime (sometimes also referred to as Sea Foam) and are softer on one side than on the other. There is gas between the layers of lime, so that they float and often wash up on the beach.

Cuttlefish are good swimmers who can cover large distances. Sometimes animals wash ashore on the coast, but more often loose back shields. They have good buoyancy and can wash up on the beach at a great distance from the place where the animal died.