Arcella

Arcella is a type of testate amoeba. These are single-celled creatures with unique, umbrella shaped shells. You can find them in freshwater places, mosses, and sometimes in soil. Arcella species have round shells and finger like parts called pseudopods that come out of a middle opening. Their shells are made of organic stuff and can change color from clear to brown as they get older. This happens because of iron and manganese building up inside. There are over 130 kinds of Arcella. This makes them one of the most varied and common groups of testacean amoebae.

Benefits
Arcella species help their environments in several ways. They eat diatoms, single celled green algae, and other tiny protozoa. This helps keep the balance of tiny creatures in freshwater places. Their special shells also give clues about the environment. This makes them helpful for studying ecosystems.

Use Cases
Arcella species live in many places. These include freshwater pools, marshes, and mosses. They are very common in eutrophic waters. These waters have lots of nutrients. Their presence can show if an ecosystem is healthy. They do well where there is plenty of food. Scientists study Arcella to learn about freshwater ecosystems. They also learn about how changes in the environment affect tiny life forms.

Additional Information
The study of Arcella species is tricky. This is because their shells look different and many species are not well described. For example, Arcella hemisphaerica and A. rotundata were once thought to be different. Now they are seen as one group with many similar looking types. Similarly, Arcella gibbosa is hard to tell apart from A. hemisphaerica and A. intermedia. More information and study are needed for clear answers.