by Dr. Robert Berdan
October 15, 2024

The Structure and Function of a Light Micvroscope.

Fig 1. A snowflake crystal collected in my back yard and magnified 20X.

Some of nature’s most exquisite handiwork is on a miniature scale – just look at the beauty of a single snowflake with a magnifying glass (R. Carson, 1965). Beauty involves a combination of qualities, including shape, colour, and form, that pleases the aesthetic senses especially the sight, but beauty can also include music and even taste. Things that are beautiful can include humans, landscapes, sunrises and works of art. Beauty can be both objective and subjective and depends on the emotional response of the observer. As a photographer and as a scientist I seek out beauty in nature and try to capture it with my camera. Searching for beauty is my way of celebrating life. I first became fascinated with a microscope in grade school and was amazed to find another world that was invisible to our eyes yet was all around us. Wanting to share the micro world with others led me into photography.

Fig. 2. Bacterium (Chromatium sp.) found in pond water. The bacterium oxidizes sulfide to produce sulfur granules which appear as yellow granules inside the cell. This large bacterium was first discovered by Maximillian Perty a German naturalist in 1852. You can also see a single long flagellum, hair-like structure which propels it. 630X by Differential Inference Contrast (DIC) microscopy.

When I first received a microscope, and later a camera, it steered me toward a career in cell biology. After more than 50 years of studying cells and nature I have now come full circle to where my interest began. Now I concentrate on photographing the micro world. I think in part I find it exciting because few people get to see this amazing and miniature world.

Fig. 3. Starch grains created by squashing a piece of raw potato on a microscope slide and viewing it with a polarizing light microscope. 200X.

Our bodies of are made up of billions of tiny cells that must communicate and work together. Cells were discovered with a primitive compound microscope by Robert Hooke in 1665. Bacteria live inside our gutand improve our health and digestion. We still have so much more to learn about cells, how they function in our body, influence our health, help us learn, remember, fight disease, and age.

Light microscopes are important tools for understanding how cells work. It was the development of light microscopes in the early 1600’s that helped us understand the basis for infectious disease. A light microscope can be purchased for less than the cost of a cell phone. I enjoy the fact that I can find interesting specimens in my backyard and close to my home. You can see living cells by scraping the inside of your mouth to observe your cheek cells and by examining a blood sample from a pin prick. Microscopy can be enjoyed at home year round. Some specimens like potato starch grains may be stored in your fridge or cupboard (see Fig. 3).

In this article I share some of my favourite photomicrographs and hope it might inspire others to examine this amazing world. Microscopes are relatively easy to use even by children, and for young children I recommend giving them a magnifying lens. This kind of learning is experientially based and promotes keen observation and thinking. Curiosity about the natural world is the only prerequisite. 

Fig. 4. Cross section of a blue spruce branch (Picea pungens) from my front yard. The section was cut with a razor blade, stained with Toluidine blue and examined by DIC microscopy at 50X. To learn more about DIC microscopy and other methods see Differential Interference Contrast (DIC) Microscopy and other methods of producing contrast (R. Berdan 2021).

The number of different micro-organisms is astronomical and thousands of different species can be found in a single pond. It is not necessary to be able to identify what you find, but rather it is more important to consider and appreciate how some of these organisms survive, feed and interact with their environment. Also think about what the specimens might be able to teach us and how they might prove useful – yeast for instance is essential in baking and brewing. Yeast is made up of single-celled microorganisms classified as members of the fungus kingdom and is capable of converting sugar into alcohol and carbon dioxide.

The micro world is all around us. We don’t have to travel to other planets to see these alien-like organisms and a microscope can be purchased by anyone that really wants one. There are two main types of cells, eukaryotes (also spelled eucaryotes) which have a nucleus that holds genetic material (DNA and chromosomes). The second major type of cell includes more primitive prokaryotes (also spelled procaryotes) where their genetic material Deoxyribonucleic acid (DNA) resides in the cytoplasm of the cells. These cells lack a nucleus and other membrane bound organelles. Prokaryotes include bacteria, blue-green algae, and Archea. All living organisms are composed of one or more cells. Some organisms contain only a single cell while other organisms are called metazoans. Metazoans comprise all animals having a body composed of cells differentiated into tissues and organs (multicellular).

Fig. 5. Above is a yeast cell used in baking (Saccharomyces cerevisiae). The nucleus is surrounded by a nuclear membrane - shown on the right filled with dark flocculent material inside. Numerous other organelles are visible in the cell which are involved in digestion, excretion, food storage etc - phase contrast microscopy 1000X.

Fig. 6. Tardigrade (a.k.a water bear), a metazoan made up of several different types of cells. Tardigrades are about 0.5 - 1 mm in size and exhbit eutely - they have a fixed number of cells. This one was found living in lichen growing on a Mountain Ash tree in my backyard. It was viewed by polarized light microscopy and dark field microscopy at 400X. Tardigrades can survive in some of the harshest conditions on earth and even survive short exposures in outer space (see podcast by NASA).

I use a wide variety of different types of light microscopes for photography. Scientists have developed different techniques to add contrast and colour to specimens. Some of my specimens are stained before viewing them by bright field microscopy. Below is a small pond organism that belongs to a group called water fleas (Chydoridae). This specimen was unstained and viewed with a bright field illumination microscope.

Fig. 7. Chydorid (Alonella sp. Identified by Dr. Robert Walsh). These tiny organisms are smaller than a millimetre, have two eye spots and pink-orange colored hemolymph which transports oxygen. The organism is multicellular and the hemolyph is pumped by a heart. Photographed at 400X by bright field microscopy.

Fig. 8. Copepods are found in both salt and fresh water and they are about 0.5 mm in size. They provide food for fish and also feed on smaller organisms. They have a single eye between their antenna and are sometimes called a "cyclops". The eggs are carried by the female near their posterior end. They can move quickly to avoid predators and they sense when you are trying to collect one with a pipette. This organism is also multicellular.

Fig. 9. Shown above is a rotifer, Brachionus manjavcas. Rotifers are small metazoans that contain approximately 1000 cells and they exhibit eutely. Rotifers live in fresh water and are eaten by small fish, copepods and even single celled ciliates like Stentor shown below. The Stentor is composed of a single cell yet it feeds on smaller, but more complex multicellular organisms like rotifers. The Brachionus rotifer above was was stained with a fluorescent dye called Acridine orange and viewed with a fluorescent light microscope at 200X.

Fig. 10. The above image is of a cross section through two pine needles that have been stained and photographed by bright field microscopy 400X. You can see smaller cells that make up the tissue. Many of the cells are involved in photosynthesis and the transport of water and sugars to the tree stem and roots.

Some organisms are made up of only a few cells like the Alga below. They belong to the group called prokaryotes which includes bacteria and blue-green algae (a.k.a. cyanobacteria). These organisms do not have a nucleus and are believed to be the first to produce oxygen.

Fig. 11. Chroococcus giganteus is a blue green algae (prokaryote) found in fresh water. The individual cells can reach 60-80 microns in diameter (micron = 0.001 mm) which is very large for a prokaryote hence its' name C. giganteus.

Below is a eukaryotic cell which has a distinct nucleus (largest sphere) with a membrane surrounding the DNA which is often condensed in the form of chromosomes. The chromosomes are made up of Deoxyribonucleic acid (DNA) and associated proteins. This cell was found in pond water and appears to be a rounded amoeba. Note the other vesicles and vacuoles inside the cell form additional intracellular compartments.

Fig. 11. Above photomicrograph shows an amoeba from pond water and taken at 1000X using phase contrast microscopy. Note the similarity in cell structure with the yeast cell above in Fig. 5.

Fig. 12. Amoeba proteus exhibiting a more typical appearance. The nucleus appears stippled and a diatom (curved shaped structure) is shown above the nucleus. Amoeba move slowly by extending their protoplasm called false-feet or pseudopods (temporary cell extensions). Our bodies contain ameoba-like cells within our blood stream that play a role in our immune system by ingesting bacteria and other pathogens.

 

Fig. 13. Above is a ciliate called Stentor coeruleus. This organism is trumpet-shaped, large (1-2 mm), single-celled and lives in pond water. Stentors contain smaller green single-celled algae (Chlorella) living inside them that are symbiotic (mutually beneficial). Stentors are covered in cilia - small hair-like structures that allow it to propel itself and sweep food into its' mouth. Hence it belongs to a group of organisms called ciliates. It was photographed by bright field microscopy and is unstained at 200X. Although Stentor coeruleus was quite well studied through the mid-1900s, the inability to grow cells at high densities and the inability to perform genetic crosses due to low mating frequencies persuaded scientists to turn to better biochemical and genetic models for study. Almost any piece of a Stentor can regenerate as long as it contains part of the macronucleus and a small portion of the original cell membrane/cortex. The macronucleus in Stentor is polyploid (contains numerous DNA copies).

 

Fig. 14. Paramecium are slipper shaped ciliates capable of moving quickly. They are shown above after being attracted to a coloured light visible in the background. Paramecium are found in pond water and feed primarily on bacteria and plant matter aiding in decomposition. To feed them I add rice grains which promote the growth of bacteria. Paramecium have been used for genetic research and may have been first observed by Dutch pioneer of microscopy, Antonie van Leeuwenhoek. In first year University I had the privilege of attending a laboratory about paramecium from Dr. Tracy Sonneborn who spent his life studying them. At the time I was an undergraduate student at the University of Western located in London Ontario. These paramecium were photographed at 100X using DIC microscopy.

Fig. 15. Above is a single cell alga that belongs to a group called desmids (Class Zygnematophyceae) within the Plant Kingdom. It contains green chloroplasts and it is bilaterally symmetrical. This particular desmid (Micrasterius radiosa) is found in ponds and lakes. They are used by scientists as bioindicators of the health of the environment because they are sensitive to pollutants and heavy metals in the water. Bright field microscopy 400X.

Fig. 16. Volvox is a species of freshwater green algae. They form hollow colonies made up of 500 to 60,000 flagellated cells and can sometimes be seen by eye. The individual cells have eye spots and the cells can swim in a coordinated fashion. Inside the hollow ball of cells are smaller daughter colonies that need to be released (see below Fig. 17). Volvox is believed to have been one of the progenitors of multicellular organisms (M. W Herron, 2018). Dark field and polarized light microscopy 100X.

 

Fig. 17. Volvox releasing daughter colonies. These daughter colonies are inside out at first with the flagella facing inside; their flagella are inverted when the colonies are released.  Dark field and polarized light microscopy 100X.

Fig. 18. Hydra contains three layers of cells (multicellular). Brown hydra, Hydra oligactis is found in fresh water ponds and lakes and is often attached to water plants. Hydra is able to regenerate and unlike other organisms does not age. Researchers are trying find what genes permit this organism to survive without aging. The only other cells that do not age are cancer cells that will live as long as they have a food supply. 25X by dark field microscopy, this organism was 0.5 mm in size, but they can grow as large as 5 mm in length.

 

Fig. 19 Hydra attacking a water flea (Daphnid). On the Hydra tentacles are stinging cells which can paralyze water fleas. Once the Daphnid is paralyzed, the hydra pulls the entire Daphnid inside to its' digestive cavity. You can also see a bud growing from its body wall which is one of the methods Hydra reproduce. 25X by dark field and polarizing microscopy.

 

Fig. 20. The image above shows a hydra engulfing a whole water flea (Simochephalus sp) it has captured. Dark field microscopy 25X.

 

Fig. 21. Copepods are found in open water of ponds, lakes and oceans. The extra long antenna identify this one as belonging to the group Calanoida. They are about 1-5 mm in size and represent one of the most common forms of zooplankton. They provide food for fish and corals. Polarized light microscopy 50X.

Fig. 22. Polyphemus pediculus is another kind of water flea that is made up of numerous cells. On its' head is a large compound eye which it uses to find prey. This water flea is found in fresh water and are collected with a plankton net. 200X dark field microscopy.

Other single celled organisms include diatoms and radiolarians. Diatoms are common in fresh water and form ornate silica shells. Radiolarians also form ornate shells, but by are found in the oceans (T. Biard, 2022). They are collected with plankton nets.

Fig. 23. Radiolarians are unicellular predatory protists encased in elaborate globular shells that are made of silica and pierced with holes. They are about 0.1 to 0.2 mm in size. Ernst Haeckel, a German zoologist and artist drew and painted them. His books and artwork are still collected today and are available online. DIC microscopy 400X.

Fig. 24 Phacus sp is a single-celled organism that is leaf shaped and covered with a rigid pellicle. These organisms use chlorophyll to produce food but are also capable of feeding on small bacteria. Phacus belongs to the phylum Euglenozoa. They have a long flagellum (not visible in photo) used for locomotion and share characteristics of both plants and animals. Note red eyespot. 630X DIC microscopy.

Fig. 25. Testudinella patina is also called a turtle rotifer. These small metazoans are found in pond water and are about 0.5 mm in size. They were named because of their shell-like circular lorica. They can retract their ciliated head and foot. They swim by rotating their flattened bodies and are propelled by cilia around its head and mouth. The cilia also sweep small algae and bacteria into its gut and it has a small retractable tail. On the head it has two red eye spots, 200X DIC microscopy.

 

Fig. 26 Fresh water snail (Helisoma trivolvis) embryo in its egg 200X DIC microscopy. They are found in fresh water ponds throughout North America. Eggs are laid in a clear transparent jelly-like substance, along with approximately 20 other eggs. The snails develop from single cells to adult snails in about 2 weeks and it's possible to observe their development with a light microscope. 50X DIC microscopy.

 

Fig 27. A young fresh water snail (Helisoma trivolvis) found in ponds - it's about 1 mm in size. A pond weed leaf (Lemna minor) is shown in the lower right along with some of its roots. 25X dark field microscopy.

 

Fig 28. Shown above are scanning electron micrographs of isolated brain cells from Helisoma trivolvis grown in culture. These pictures are from my research studying how neurons regenerate and form synaptic contacts in culture. Scanning electron micrographs are in black and white, but they can be hand coloured. The one picture on the right I artificially added human eyes using a darkroom enlarger. I did this to attract interest by other scientists to a poster presentation and it caught the attention of National Geographic. The small horizontal bars with 5 U@ below them represent a scale bar 5 microns in size. One micron = 0.001mm. Photos were taken at about 5,000X. These cells were examined with a scanning electron microscope (SEM), the neurons were first fixed, critical point dried, and then coated with a gold film to reflect electrons.

 

Fig. 29. The specimen is of a midge fly larva (Chaoborus sp) which are found in pond water. It was photographed using a polarizing light microscope. The polarized light causes muscles to appear yellow and blue. The muscle fibres and proteins are regularly arranged and appear crystal-like in polarized light. Additional colour was introduced by using a retardation filter (M. Davidson), 50X.

Fig. 30 Chaoborus sp feeds on water fleas like the one shown in the top right of the image. Chaoborus develops into non biting midge flies. This image was taken using a combination of polarized light and dark-field microscopy at 100X. To learn more about the midge fly larva see my article about Chaoborus.

 

Fig. 31. A gastrotrich is shown above. They are small metazoans 0.06 to 3.00 mm in size and found in ponds. They are sometimes called hairy backs and you can see spines clearly in another species i below taken at higher magnification. Gastrotrichs belong to their own phylum and are made up of approximately 1000 cells and exhibit eutely. They live on plants and at the bottom of ponds and lakes and there are some terrestrial species that live in the film of water surrounding sand grains. They feed on detritus and are hermaphrodites, an organism that can produce both male and female gametes. They reproduce by parthenogenesis (without fertilization). Gastrotrichs grow and mature within a few days and swim rapidly through the water. The ventral side of the organism bears long rows or patches of cilia which it uses to propel itself. See Wikipedia for more information.

Fig. 32 Above is a picture of a gastrotrich taken at 630X with DIC microscopy. They often carry eggs inside their bodies. Their mouth is on the anterior end (on top right of the picture).

 

Fig. 33. A mosquito larva also called a wriggler. They live in pools of water and develop into biting mosquitoes in about 10-14 days. They feed on water fleas, detritus, bacteria, protozoa, algae and other small crustaceans. 50X DIC microscopy.

Fig 34. Caddisfly larva (Oxyethira sp) sitting top of a silk house it built. Caddisflies use a wide variety of materials to make their house including stones, wood, eggs and other debris. Most caddisflies undergo metamorphosis into an adult. There are about 15,000 species, many live in rivers and ponds. They usually live in their casings and wait for food to come to them. Most adults have short lives during which they do not feed. Caddisflies are also bioindicators as they are sensitive to pollution. Fisherman use caddisflies as bait. Polarized light microscopy 50X

Fig. 35. Swimmer's itch, also called cercarial dermatitis, appears as a skin rash caused by an allergic reaction to certain microscopic parasites that infect some birds and mammals. These parasites are released from infected snails into fresh and salt water (such as lakes, ponds, and oceans). The parasite attaches to animals and humans that enter the water. These parasites can't survive in people, so they soon die. This specimen was collected in a pond near the Bow habitat fisheries in Calgary. DIC microscopy 200X.

Fig. 36 Painted lady butterfly photographed with a stereo microscope at 36X using a technique called focus-stacking. Though this butterfly was not microscopic in size the hairs on the head and eyes are. For low magnification work stereo microscopes are often used in identifying larger organisms like insects.

Fig. 37. The photo above shows a small amphipod crustacean (Hyalella azteca) found in many fresh water ponds and lakes. It can reach 2-8 mm in size and was collected in a small pond just north of Calgary. They are identified from other species by having sharp spines on their dorsal plates called pleosomes. This one was photographed with a 2.5X microscope objective using top lighting from a fibre optic lamp. Total magnification 25X.

Fig 38. Dandelion floret 100X DIC microscopy. When dandelions turn white they form about 200 florets on a single flower head. The florets are blown about by the wind.

 

Crystals by Polarized Light Microscopy

When it comes to spectacular colours and shapes, crystals are some of the most beautiful subjects I have seen with a microscope. The crystals are made by drying chemicals on a glass microscope slide, melting, or freezing them. The chemicals can include vitamins, drugs, callus remover, and amino acids. I describe the processes I use to make the slides which are then viewed with a polarizing light microscope. These microscopes often contain an additional filter called a retardation plate that introduces additional colours in thin scrystals (M. Davidson). The colours and the orientation reveals information about the molecular properties of the crystal, its refractive index, and orientation. See other articles on this site about the crystals and the methods I use to make them.

Fig. 39. Vitamin C crystal by polarized light microscopy 50X.

Fig. 40. Amino acid crystals by polarized light microscopy 50X.

Fig 41. Wine crystals by polarized light microscopy 50X.

Fig. 42. Wine crystals by polarized light microscopy 50X.

Crystals offer complex and beautiful patterns and an incredible palette of colours. Some chemicals are cheap and easy to work with (e.g. Vitamin C, callus remover, amino acids). If you are interested in learning to make and photograph crystals with a microscope I offer workshops out of my home and can accommodate up to 3 persons - see my workshops page for more information. I provide cameras, polarizing microscopes, computers and software in the workshops and a wide range of chemicals - contact me if interested.

Summary

I have shown a small selection of specimens viewed with various kinds of microscopes. Live organisms are the most interesting subjects for me. Some folks gravitate to astronomy or birding as a hobby. If you are curious, enjoy nature and science, then I would encourage you to consider microscopy as a hobby or as a profession. Start in your backyard, nearby river, pond or ocean if available. Collect water from your eves trough or bird bath. If you own a cell phone with a camera you can capture pictures and movies.

Some parts of the world offer microscopy clubs and workshops. In Canada, microscopy clubs are scarce or restricted to students and faculty at universities. At one time microscopy was a popular hobby among gentlemen in Europe. I believe every school with students above grade 6 should have at least one microscope. Microscopes encourage experiential learning and self discovery.

Any student in Calgary in Grade 6 or higher wanting to learn more about microscopy is welcome to visit me along with one of their parents to learn about microscopy. I would be happy to provide a couple of hours of free instruction on how to use a microscope and where to collect specimens (science and art teachers are also welcome). I also accept invitations to present at schools and libraries (for a modest honorarium to cover my costs and transportation).

Additional References

Rachel Carson (1965) The Sense of Wonder.  Photographs by Nick Kelsh. Harper Collins Publishers. Amazon.ca.

Ernst Haeckel (2020) The Art and Science of Ernst Haeckel by by Rainer Willmann (Author), Julia Voss (Author). Hardcover. Published by Taschen. Available on Amazon.ca

M.W. Davidson Introduction to Compensators and Retardation Plates.

R. Berdan (2020) Photography of Chaoborus the phantom midge fly larva - Zooplantkton's Nightmare.

R. Berdan and B. Berdan (2023) The Science & Art of Wine Crystals by Polarized Light Microscopy - Abstract Art

T. Biard (2022) Diversity and ecology of Radiolari in modern oceans. Environ Microbiol. 24: 2179-2200 PDF

R. Berdan (2021) Differential Interference Contrast (DIC) Microscopy and other methods of producing contrast

R. Berdan (2019) The Micro-Universe - Microscopic Life.

M.W. Herron (2018). Origins of multicellar complexity: Volvox and the volvocine algae. Mol. Ecol. 2016 24: 1213_1223 PDF

Microscopy Society of Canada - I attended a meeting in Montreal to present some work about 3 decades ago.

The Micro-Naturalist - web site and club by John MacFarlane - British Columbia.

See other articles on this web site for more information, images, movies and different types of light microscopy.

Note: Educators and students may use my images freely for reports and teaching. For commercial use please contact me. If you use my images online I appreciate attribution and a link back to this web page. All images are available for personal and commercial use.

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Authors Biography & Contact Information

Bio: Robert Berdan is a professional nature photographer living in Calgary, AB specializing in nature, wildlife and science photography. Robert retired from Cell\Neurobiology research to pursue photography full time many years ago. Robert offers photo guiding and private instruction in all aspects of nature photography, Adobe Photoshop training, photomicrography and macro-photography. Portrait of Robert by Dr. Sharif Galal showing some examples of Robert's science research in the background.

Email at: rberdan@scienceandart.org 
Web sites: www.canadiannaturephotographer.com 
                        www.scienceandart.org
Phone: MST 9 am -7 pm (403) 247-2457.