Do You Share This Love for a Family of Rotifers and Why Should You Care?

a freshwater rotifer filtering water by flagella, hunting (Shutterstock)

I must admit I never heard of the Rotifer family, certainly never saw one, and only became acquainted through researching about Nature’s ecosystems. Suddenly, there were a host of words describing their features and functions … encystment, slime glands, statoblasts, cilia, threadlike shaft surrounded by barbs, animal jelly locomotion, or battery of nematocysts discharged for prey and defense.

And there were pictures, even photographs, of these microscopic beings looking like tiny aliens scurrying here and there or cemented to the ground, eating and reproducing with so many intricate shapes with pulsating organs, many symmetrical and some telescopic.

Then the initial fascination was compounded by science to explain their purpose and value in their environment and ecology in general and I became their biggest fan!

They are related to Protozoans who are single celled organisms who may live in solitary or colonial forms. They can either be free moving with flagella (tails), false feet or be sessile (attached). Each body is contained within a cellular wall, a nucleus and even chloroplasts for photosynthesis. They eat bacteria, algae, or other protozoa and live in all aquatic or moist environments.

Rotifers are known as Metazoans because they are multicellular with 900 to 1000 cells, who develop from embryos. Their roles are as scavengers, herbivores and deposit feeders to consume and recycle the habitat where they live in water including ponds, creeks, rivers, lakes, soil, and water films associated with moss, liverworts and lichens.

Their first cousins are primitive sponges, hydras, jelly-fish and anemones. Other cousins are the Hydrozoans who develop polyps and usually live in colonies. Other relatives are the flatworms, both freshwater and terrestrial, along with flukes, tapeworms and flatworms.

Rotifers have a unique classification, Rotifera, which means “wheel animals” with complicated feeding and locomotor organs. Their many different cylindrical or squat bodies are covered with transparent elastic skin containing a mouth, pharynx, salivary gland, stomach, reproductive organs and anus and sometimes a foot or spur with two pointed toes on the bottom. Most distinctively, they sport a ciliated crown or corona, a sweeping vibrating rim of cilia (hair) that creates currents to catch minute organic particles into their mouth. They may also be carnivorous, feeding on protozoans or other metazoans.

Talk about their families being an unique matriarchal society. Some species consist only of females that produce their daughters from unfertilized eggs. The smaller males, without any alimentary canals, survive long enough to produce sperm that fertilize some eggs which then form resistant zygotes that can survive if the local water supply should dry up. Several kinds of eggs with intricate designs are produced which are laid on algae or carried about attached to their bodies. Some eggs are developed inside the females’ bodies and the young are born well-developed.

A few rotifers can encyst themselves inside a thick protective skin into a dormant desiccated state and when placed in water, can rapidly absorb water to swell up and resume their former rotifer shapes. In fact, some scientists refer to them as “time travelers,” because as a cyst they can survive for decades without any signs of aging. Imagine if we had such power of reincarnation.

Most importantly, rotifers are highly reproductive and play a critical role in the microbial or nutrient loop within freshwater lakes and rivers, being a major food source and contributing to the decomposition of soil organic matter. A typical food web might start with a large fish eating a smaller fish eating an insect eating a rotifer eating a protozoa eating bacteria. If rotifers were suffering contamination and loss, the entire food chain would eventually collapse. In fact, rotifers are good indicators of water quality and dissolved oxygen content and more scientific studies are looking at their effects on environmental restoration.

The most important lesson of all is that microbial communities are not haphazard aggregations of species thrown together by nature but rather structured communities with numerous interlocking cause and effect connections. Their sensitivity is the first to react to any changes and must be respected.

But I’m not a scientist given to writing about technical studies; I’m a teacher and eco-fiction writer who wants to materialize ecology as a tangible force within which we can walk and talk even if fictional. How can I bring such an amazing, fantastic, important ecological character to life?

Imagine living in a fresh-water pond as she moves about describing her lifestyle, family members, nursery, friends, food supply and even enemies. She talks about the power of her cysts, her feelings toward the essence of water that nourishes and protects her in a loving way. Then comes the news of a chemical processing plant to be built on the shoreline and the specter of pollution rises its ugly reflection sinking to bottom depths. Then what happens when her fears are realized and a horde of pollutant scavengers invade her home like leeches, rat-tailed maggots, sludge worms, tubifexes, blood worm midges and mosquito larvae who are best adapted to oxygen starved water.

Who best to describe this disaster except a rotifer who lives there? How can this tiny, vulnerable, vital being make a connection to the world of humankinds?

I hope you have learned a few facts about the Rotifer family and consider them your worthwhile acquaintances, too. When you eat a piece of fish or anything else that comes from nature, be grateful for these tiny organisms near the bottom of the food chain.

Someday, I would be thrilled to see an a real rotifer under a microscope sweeping across the glass, but until then, my admiration and imagination will have to suffice.

Comments are always welcome. Call to set a time to talk: 833 471 4661

Annemarie Berukoff

Now it’s the rotifers’ turn, and again my heart-mind is into unbelievable observation …. Great Sweeping Coronas! In their usual manner, the rotifers all turn upside down to stand on their heads, wave their hair rapidly, and break up the remaining jelly mass into little bits and pieces which are then sucked into the open spaces at the top of their heads. Well, I must admit, that seeing a mass of beings standing upside down and waving their hair while eating through a hole on top of their heads is one of the strangest sights I will probably ever see, according to Nature’s plan.

Excerpt: The Incredible Journey of a Water Sprite with Roots …on his mission to discover Earth’s Cyclical Truths.

Check Index



Get the Medium app

A button that says 'Download on the App Store', and if clicked it will lead you to the iOS App store
A button that says 'Get it on, Google Play', and if clicked it will lead you to the Google Play store
Annemarie Berukoff

Annemarie Berukoff


Retired teacher — Big Picture Wisdom, activist, author 4 e-books: social media teens, eco-fiction ecology