Скачать или смотреть Volvox algae spinning 💫

I found sooooo many Volvox last week! I couldn’t stop looking at them, I took around 150 videos 😅

Volvox is a genus of multicellular freshwater free-swimming green algae. It is largely used for developmental biology, and to study the transition from single celled to multicellular forms of life. Can you see how these spherical photosynthetic beauties are creating a water flow around them? They propel all of the other organisms further around 😂

The larger spheres are colonies of small biflagellate cells with smaller aflagellate round colonies inside which are the daughter colonies, or the baby algae. Specialized biflagellated cells are responsible for locomotion and spinning movements toward a light source so they can produce sugar by photosynthesis. Those biflagellated cells also possess an eyespot which is responsible for detecting light and guide the colony towards optimal light conditions. These flagellated cells that compose the large mother colony are all interconnected by small cytoplasmic bridges to allow nutrient transfer and communication between cells. Those bridges are a bit hard to see but still visible in the clips with the white background (brightfield)!

In other words, a Volvox colony is typically formed of two types of cells; germ and somatic. The larger sphere is composed of thousands of somatic cells responsible for photosynthesis and motility. These cells create a water flow around the colony, but they cannot divide and are programmed to die within a few days. Germ cells are nonmotile, but can divide asexually and form new little daughter colonies. These generative cells are basically responsible for  Volvox’s growth and reproduction and are practically immortal!

When the mother colony breaks open, the young colonies can escape and start their life! The cycle can then start again ☺️

Bubbly soundtrack is a courtesy of ‪@aperfectsong13‬ 🌀

Video taken with my iPhone mounted on my brand new BA310E Motic microscope with an @ilabcam adapter 🔬

References:
David L. Kirk, Germ–Soma Differentiation in Volvox, Developmental Biology,
Volume 238, Issue 2 (2001)

Fenchel, T. (2013). Ecology of Protozoa: The biology of free-living phagotropic protists. Springer-Verlag.

Umen, J.G. Volvox and volvocine green algae. EvoDevo 11, 13 (2020)