Today we will look at another representative of the world of unicellular microorganisms, Stentor, a shapeshifting herald blowing its own trumpet!
Size & appearance
When we think of microscopic organisms, we usually imagine tiny creatures that are invisible to the naked eye. However, not all microbes are so small. Some of them can reach impressive sizes, such as the stentor, a genus of filter-feeding ciliates that can grow up to 2 millimeters long. That may not sound like much, but it is larger than some of the smallest multicellular animals, such as rotifers and tardigrades.
To date, scientists know of 22 species in the genus Stentor, belonging to the class Heterotrichea. Stentors can swim quickly in the water column, but most of the time they prefer to remain attached to the substrate. Once attached to the substrate with the lower part of the holdfast, the Stentor begins to stretch out and open its peristome. At this moment, the Stentor looks like a horn, a musical instrument used since ancient times.
The movement of the cilia around the peristome creates a flow of water that brings nutrients, such as suspended particles, waste products and bacteria, to its mouth, also known as the cytostome. However, algae, which also enter the infusoria, are not the true source of food. Instead, the stentor and algae have developed a symbiotic relationship, like corals in symbiosis with algae. The stentor receives additional nutrition from the photosynthetic activity of the algae, and the algae in turn receive protection and essential nutrients from the stentor’s waste products. Different types of algae ingested by the stentor give different color variations to the animal.
Stentor will attach to glass, soil, decoration and plants in areas of the aquarium with low current. These beautiful microorganisms pose no danger to the fish, shrimps and snails in your aquarium.