Video: https://youtu.be/lSif6qvuMEQ

Sampling location: A sand sample was collected from Adzghapsha Beach, located on the coast of the Black Sea. The sand was almost dry at the time of collection.
Date and time of collection: September 9, 2023 at 11 AM
The sample was stored in a sealed glass container at room temperature.
In about a week, a small amount of this sand was mixed with
saltwater prepared from distilled water and marine aquarium salt to achieve a salinity of approximately 20 g/kg. However, determining the precise salinity level is impossible without a salt meter.
Date and time of observation: September 22, 2023 at 11 AM

All 100x objective images and videos are of the same organism.
All 10x and 40x objective images and videos are of a few other ciliates from the same water sample.

Diagnosis of the organisms observed:
• Slender, flexible cell
• Three longitudinal cortical grooves that allow the cell to spiral the anterior half of the cell
• Spiral movement when swimming
• Length 60-75 µm
• Colorless cortical granules widely distribute in the cortex
• Buccal opening approximately one third of total length
• A clear subequatorial CV. At least two other small vacuoles were visible in line with the large CV at the posterior part of the cell

Unfortunately, I am not sure about the other important features, such as the nuclear apparatus and the arrangement of the kineties. The tendency of this ciliate to bend its body in a spiral and my lack of experience confused me.

Magnification of photos: 100×, 100×, 100×, 100×, 200×, 200×, 200×, 200×, 400×, 400×, 400×, 400×, 400×, 400×, 400×, 400×, 600×
Habitat: Saltwater squeezed out of beach mud (by stepping on it), near a saltmarsh. I presume the mud was hypoxic due to its rotten-egg smell.
Photo taken with a Celestron PentaView Digital Microscope. According to their website, the FOV (i.e. the diagonal width) at 100× is 600 µm.
Videos available: https://youtu.be/FIey5h5ooyg
https://youtu.be/ifWMmM7w1us

Magnification of photos: 100×, 100×, 100×, 200×, 200×
Habitat: Saltwater squeezed out of beach mud (by stepping on it), near a saltmarsh. I presume the mud was hypoxic due to its rotten-egg smell.
Photo taken with a Celestron PentaView Digital Microscope. According to their website, the FOV (i.e. the diagonal width) at 100× is 600 µm.
Video available: https://youtu.be/AoxdmozIkyM