Don't keep wakame in the fridge for too long

Wakame has an olive green to brown color. It is a rubbery, long, smooth, single leaf with wavy edges, growing to almost two meters in length. Just above the root of wakame is a germ (mekabu) that is particularly mineral-rich and also suitable for consumption.

After nori and kombu, wakame is the most commonly used seaweed in Japanese cuisine. One of the richest sources of calcium. Rich in vitamin B and vitamins A, C and K. High concentrations of protein, iron, magnesium, iodine, sodium, chromium, zinc, phosphorus and potassium.

The wakame in the video has been in the fridge for too long. It was intended to make a tuna dish on a bed of this type of algae. Unfortunately there is now mold on it... Something for under the stereo microscope.

On the high magnification of the last images you can notice that in 2 places clearly conidiophores and the formed conidiospores develop on the upright hyphae:

• Approximately in the middle of the image at the transition of the white mycelium
• Top rightmost 

It is though that we are dealing here with a Penicillium species (simpler conidiophore and single short rows of globular conidiospores) than an Aspergillus species (more globular branching at the end of a conidiophore).

With thanks to Dora De Cremer PhD

© willemsmicroscope.com

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.

Algae Bloom

 

These beautiful golden spheres are single colonies of the golden algae synura. Like all other organisms, synura is able to reproduce and one colony eventually turns into two. But when conditions are right, reproduction happens a lot more frequently and what used to be a few colonies can quickly turn into an enormous algae bloom. Even though each synura colony is microscopic and only measures around 20-30 microns in diameter. Their large numbers in an algae bloom are able to turn the water in their freshwater habitats a yellowish brown color. A bloom of synura like the one in the image usually happens in spring and fall when the water is cold. But not all algae will bloom in cold water.

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?

Synura - The golden algae

When we hear the word algae many of us associate that with the color green. And some algae like desmids, are in fact green. But there are a lot of different kinds of algae, and far from all of them are green. Some are red or red and green like haematococcus, some are blue-green like spirulina, while others are yellowish, brown, or even golden.

Haematococcus pluvialis - The red colored green alga

Haematococcus pluvialis is a single celled green freshwater alga found all over the world. Each cell is encased in a transparent capsule and varies in size from 10-50 microns depending on its life cycle stage, but most are around 20 microns. H. pluvialis can be found in two major stages, active and inactive. In the active stage the algae are motile and move with two long whip-like projections called flagella. In the inactive stage the cells become non-motile encased cysts which are able to tolerate periods without water and huge temperature fluctuations. One of the protective strategies the algae use during the non-motile stage is the production of a molecule called astaxanthin.

Desmids - Beautiful single celled algae

There are many different types of algae, differing in both size, shape, color, habitat and more. Some types are multicellular and very large like seaweed, some are microscopic and colonial like Eudorina, while others consist of only a single cell. Some of these are called desmids (desmidiales).

Desmids are highly symmetrical unicellular green algae which can take on many different shapes depending on the specific species. The desmids also vary in size between species, the smallest being only a couple of microns and the largest reaching a size of several hundreds of microns and are visible with the naked eye. Desmids are most commonly found in freshwater where several thousand species can be found.

Euglena - part plant, part animal

Cells with a nucleus are called true cells, or eukaryotes, which can be further subdivided into kingdoms like plant and animal. Plant cells and animal cells are different in their components and structure, but some organisms does not fit as neatly into these little boxes and can be tricky to place on ‘the tree of life’. One of these is the single celled organism euglena.

Euglena with clearly visible red eyespots

Stentors - some of the largest single celled organisms in the world

Stentors are trumpet shaped single celled organisms found in freshwater habitats like pods and streams. Due to their shape they are more commonly known as trumpet animalcules. Stentors are some of the largest single celled organism in the world, with the largest species reaching a size of up to two millimeters, and it is therefore possible to spot them in a water sample without a microscope. Stentors are ciliates, which mean that they move and feed with tiny hair-like projections called cilia. They have a large number of these cilia surrounding the mouth which creates a current of water carrying food particles for ingestion. In the opposite end they have a foot which is they use to adhere to a substrate.

Observe the classic trumpet shaped appearance and the clearly visible cilia surrounding the mouth.

Eudorina - a colonial algae

Eudorina is a genus of green freshwater algae. Each eudorina are multicellular colonies consisting of 16, 32 or even 64 individual cells held together by a gelatinous substance made of sugary proteins, or glycoproteins to be a bit more scientific. The individual cells in a colony are not much larger than our blood cells, and the entire colony is about the same size as the width of a human hair. The green color is due to the presence of large chloroplasts inside each cell used for energy production through photosynthesis.

Note the gelatinous transparent matrix surrounding each colony.

Volvox bloom

Volvox is a popular alga among microscopists because of the beautiful images it produces under the microscope. The volvox in the video was unexpectedly found in a pool in Eindhoven, the Netherlands in early November 2019. There were so many of these species present that one could speak of a bloom.

The green alga Volvox is a colony of cells that have started to work together. Some cells catch the light, others provide movement or reproduction. They have become so dependent on each other that you can speak of a multicellular organism.

Cyclonexis erinus a rare organism?

Cyclonexis erinus (Chrysophytes, golden algae) is considered to be an algae, difficult to observe. The specimen shown in this video has been found in an aquatic sample taken from a small fen in the Nature Reserve ‘De Teut’ in Belgium, in February 2016 (during quite cold weather).

Only few references about this algae can be found in literature and on the internet. Only a very limited number of the species Cyclonexis sp. is known. Cyclonexis sp. lives in cool, lime poor mountain waters and in acid fens containing Sphagnum. It is mentioned that it is not so rare as is sometimes assumed. It was discovered that these algae disintegrate very quickly when external conditions are changing, causing it to disappear from the aquatic sample.

Easy observation and filming of plankton

When investigating water samples within the framework of hydrobiology, it is very easy to observe and film plankton with the Motic AE31E inverted microscope and the Moticam 1080 camera. The plankton containing water sample is stored in a culture dish, the bottom of which is formed by a calibrated cover glass. The dish is simply placed on the microscope stage. The Moticam 1080 is connected to a monitor. As soon as an interesting organism appears on the monitor screen, it only needs a simple mouse click to record the image.

Synura, spring is in the air!

Synura sp. Chrysophytes or Golden Algae, are common in freshwater habitats especially in spring. These motile spherical colonies have yellow brown plastids, two flagella of different length and are covered with siliceous scales. 

Cladonia coccifera

This cup lichen is common in forests, sand dunes and heathland. It grows between moss and grass and is about half a centimeter tall. It has a red-colored spore forming fruiting or apothecia.

Lichens are tough organisms which can survive on the most unlikely places, where plants cannot grow. For example, in the desert, in the Antarctic, in high mountains.

A bio-indicator for air pollution

Growth of lichens on trees: Bio-indicator for clean and contaminated air. Lichens are dual beings, developed from a symbiosis of algae and tiny fungi. Fungi and algae alone are dependent on moisture.