Uploaded July 2026 | Updated September 2026, 2 weeks ago
A drop of pond water, one single-celled predator, and a crime I never expected to witness under the microscope.
What I filmed here is a heliozoan — a spherical "sun animalcule" whose needle-like arms radiate out in every direction — already holding a few captured algae cells when an ostracod, a tiny crustacean in a hinged shell, drifts in close. Riding on that shell is a row of peritrich ciliates. Over the next several minutes the heliozoan begins working them one at a time: sealing individuals into holding compartments, merging those compartments together, then dividing them again to isolate each ciliate in turn. Capturing an interaction like this on video is rare, and I genuinely didn't know how it would end.
I'm a hobbyist, not a professional microbiologist, so I sent my questions about what we're seeing to David Patterson, a leading authority on heliozoa. His input is woven into the video.
If you like watching the microcosmos unfold in real time, come along.
👉 YouTube: @ThaiMicrocosmos
Related: What Does a Microbe Experience as It's Eaten Alive? youtu.be/Vk080RY-02U
⏱️ Key Moments
0:00 Planning a microscopic heist
0:27 Meet the heliozoan
0:55 An ostracod drifts in
1:36 First contact — the algae are released
2:38 Isolating the ciliates
3:33 The ostracod moves
4:06 Picking off the first ciliate
5:05 Success
5:31 The ostracod escapes
5:54 Researching the behavior
6:25 Extrusomes — the hidden machinery
7:08 Why the peritrichs?
8:26 Why I keep looking
📚 Sources
- Patterson, D. J. & Hausmann, K. (1981). Feeding by *Actinophrys sol* (Protista, Heliozoa): I. Light microscopy. *Microbios*, 31: 39–55.
- Hausmann, K. & Patterson, D. J. (1982). Pseudopod formation and membrane production during prey capture by a heliozoon (Feeding by *Actinophrys*, II). *Cell Motility*, 2: 9–24.
- Linnenbach, M., Hausmann, K. & Patterson, D. J. (1983). Ultrastructural studies on the food vacuole cycle of a heliozoon (Feeding by *Actinophrys*, III). *Protoplasma*, 115: 43–51. doi.org/10.1007/BF01293579
- Sakaguchi, M., Hausmann, K. & Suzaki, T. (1998). Food capture and adhesion by the heliozoon *Actinophrys sol*. *Protoplasma*, 203: 130–137. link.springer.com/article/10.1007/BF01279469
- Suzaki, T., Shigenaka, Y., Watanabe, S. & Toyohara, A. (1980). Food capture and ingestion in the large heliozoan, *Echinosphaerium nucleofilum*. *Journal of Cell Science*, 42: 61–79. doi.org/10.1242/jcs.42.1.61
With thanks to David Patterson for generously answering my questions about what we're seeing here.
#Microscopy #PondLife #Microcosmos #Heliozoan #Protist #Ostracod #Ciliates #Peritrich #Microbiology
A drop of pond water, one single-celled predator, and a crime I never expected to witness under the microscope.
What I filmed here is a heliozoan — a spherical "sun animalcule" whose needle-like arms radiate out in every direction — already holding a few captured algae cells when an ostracod, a tiny crustacean in a hinged shell, drifts in close. Riding on that shell is a row of peritrich ciliates. Over the next several minutes the heliozoan begins working them one at a time: sealing individuals into holding compartments, merging those compartments together, then dividing them again to isolate each ciliate in turn. Capturing an interaction like this on video is rare, and I genuinely didn't know how it would end.
I'm a hobbyist, not a professional microbiologist, so I sent my questions about what we're seeing to David Patterson, a leading authority on heliozoa. His input is woven into the video.
If you like watching the microcosmos unfold in real time, come along.
👉 YouTube: @ThaiMicrocosmos
Related: What Does a Microbe Experience as It's Eaten Alive? youtu.be/Vk080RY-02U
⏱️ Key Moments
0:00 Planning a microscopic heist
0:27 Meet the heliozoan
0:55 An ostracod drifts in
1:36 First contact — the algae are released
2:38 Isolating the ciliates
3:33 The ostracod moves
4:06 Picking off the first ciliate
5:05 Success
5:31 The ostracod escapes
5:54 Researching the behavior
6:25 Extrusomes — the hidden machinery
7:08 Why the peritrichs?
8:26 Why I keep looking
📚 Sources
- Patterson, D. J. & Hausmann, K. (1981). Feeding by *Actinophrys sol* (Protista, Heliozoa): I. Light microscopy. *Microbios*, 31: 39–55.
- Hausmann, K. & Patterson, D. J. (1982). Pseudopod formation and membrane production during prey capture by a heliozoon (Feeding by *Actinophrys*, II). *Cell Motility*, 2: 9–24.
- Linnenbach, M., Hausmann, K. & Patterson, D. J. (1983). Ultrastructural studies on the food vacuole cycle of a heliozoon (Feeding by *Actinophrys*, III). *Protoplasma*, 115: 43–51. doi.org/10.1007/BF01293579
- Sakaguchi, M., Hausmann, K. & Suzaki, T. (1998). Food capture and adhesion by the heliozoon *Actinophrys sol*. *Protoplasma*, 203: 130–137. link.springer.com/article/10.1007/BF01279469
- Suzaki, T., Shigenaka, Y., Watanabe, S. & Toyohara, A. (1980). Food capture and ingestion in the large heliozoan, *Echinosphaerium nucleofilum*. *Journal of Cell Science*, 42: 61–79. doi.org/10.1242/jcs.42.1.61
With thanks to David Patterson for generously answering my questions about what we're seeing here.
#Microscopy #PondLife #Microcosmos #Heliozoan #Protist #Ostracod #Ciliates #Peritrich #Microbiology
